Method for producing a suspension of thermally exfoliated vermiculite, an extinguishing agent, an extinguishing/deactivating agent, a deactivating agent and a passive fire protection agent containing thereof, and an extinguishing appliance and an extinguisher

The present invention relates to a method for producing a suspension of thermally exfoliated vermiculite, an extinguishing agent, an extinguishing/deactivating and deactivating agent, and a passive fire protection agent, their use, and an extinguishing appliance and an extinguisher.

Vermiculite is an ecologically clean mineral that is formed in the earth's crust during the natural weathering process of biotite, phlogopite, some chlorites and other magnesium-rich silicates. Due to its properties, such as fire resistance or resistance to very high temperatures, high temperature insulation property, good sound insulation property, non-toxicity or natural resistance to the development of fungi and mold, and insolubility in water, vermiculite is widely used in many industries, including first of all in construction, agriculture and gardening, as well as being widely used for environmental protection. Vermiculite is characterized by a color from yellow, through olive to brown. It has mostly the form of plates, shimmering crystals or lamellar clusters, with the morphology diversity depending on the location of the vermiculite deposit, being mined, for example, in RSA, China, South America (Brazil and Argentina). Depending on the origin, vermiculite may differ in elemental composition.

There are different ways to treat vermiculite, namely physical and chemical methods. Depending on the method used for delamination of vermiculite, products based on it are characterized by different physical and chemical properties. The method of physical treatment of vermiculite includes, among others: high-temperature treatment and sonication using ultrasound or microwaves. Chemical methods, on the other hand, include, among others, intercalation of vermiculite with alkylammoniums or hydrogen peroxide. For example, the results of studies conducted using SEM and X-ray imaging techniques have shown that leaching vermiculite with HC1 solution causes partial transformation of its ordered layered structure into a delaminated structure. Treatment of vermiculite with a H2O2 solution leads to the separation and fragmentation of its layers without changing the structure (Hashem et al., Chemical activation of vermiculite to produce highly effective material for Pb ²⁺ and Cd ²⁺ removal. Applied Clay Science 115 (2015) 189-200). In the case of chemical expanding activated reagents such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and a hydrogen peroxide solution are usually used to exfoliate the phyllosilicates. Of these, due to the best effect of expansion resulting from the low degree of interference into the vermiculite layers, the hydrogen peroxide solution is most often used (Obut, et al., Hydrogen peroxide exfoliation of vermiculite and phlogopite, Minerals Engineering 15 (2002) 683-687). However, a disadvantage of chemically treating vermiculite using commonly known technologies is that identifiable residues of process chemicals or residues resulting from chemical reactions remain in the vermiculite particles. What is worth emphasizing, products of thermal processing are free from residues of undesirable substances. Thus, vermiculite subjected to thermal exfoliation is much more desirable for practical applications, which, due to purely physical processing, is also an ecological and environmentally friendly product.

This feature is particularly important when vermiculite-based products may come into contact with living organisms or valuable natural, architectural or urban areas. Examples of such applications include products where, in particular, the refractoriness or resistance of vermiculite to very high temperatures is employed. Commonly used water-based extinguishing agents have a significant impact on the surrounding space, destroying it, on contact, by soiling and moving objects in the vicinity. Moreover, water extinguishing agents do not stick (adhere) to the surface, but flow down it, additionally evaporating strongly during extinguishing, which slows down the action of the extinguishing agent itself and reduces its effectiveness. Such physicochemical properties make it necessary to use a water-based extinguishing agent in larger amounts and significantly extend the extinguishing process, which is unfavorable and even dangerous.

Extinguishing live electrical equipment is also problematic, because extinguishing them with inappropriate extinguishing agents can even lead to death by electrocution.

In the state of the art the use of vermiculite in extinguishing agents and extinguishing appliances is known, e.g. from European patent EP2830718. This document discloses the use of a stable aqueous suspension of fine vermiculite particles with a particle size of 1 nanometer to 2000 micrometers as a fire extinguishing agent, and extinguishing equipment containing such a suspension. Notwithstanding, as stressed in the description, the vermiculite present in the extinguishing agent suspension is chemically expanded vermiculite, which, as emphasized, ensures stability of the extinguishing agent suspension, the possibility of its storage for a longer period without losing the desired properties. However, as mentioned above, due to the presence of compounds used in the process or compounds formed as a result of a chemical reaction in the chemically expanded vermiculite, extinguishing agents based on it may, while extinguishing, release substances that are harmful to both the environment and the user, and the surroundings.

Thus, the prior art lacks a stable extinguishing agent, in the form of a suspension or paste, based on thermally exfoliated vermiculite, including a stable agent, in the form of a suspension or paste, based on thermally exfoliated vermiculite, for extinguishing and/or deactivating photovoltaic panels, electrical appliances or live electrical appliances, which not only would be effective, but also efficient, and at the same time safe for both the user and the surfaces treated with it, even when extinguishing photovoltaic panels, electrical appliances or live electrical appliances. In particular, it is desirable that such an agent be free of undesirable substances that may pose a significant threat, and during use does not pose any threat, and its use would not lead to damage or degradation of the treated surfaces. Moreover, it is desirable that the extinguishing agent, including an extinguishing and/or deactivating agent for photovoltaic panels, electrical appliances or live electrical appliances, enables the subsequent use of the appliances after cleaning the treated surfaces of its residues. In particular, an agent is desirable that covers the treated surface well, does not flow down, does not evaporate, and is furthermore ecological and does not release harmful substances during firefighting, and at the same time does not lose its properties on storage. The present inventors have surprisingly found that such a material is a thermally exfoliated vermiculite-based agent. A suspension of thermally exfoliated vermiculite itself is an effective extinguishing agent. Also, it is possible to develop on its basis specialized compositions (extinguishing, fire protection or flame retardant agents) by changing the proportions of the components of the suspension itself or introducing additional components to the suspension.

In addition, the inventors have noticed that such a new agent with unique properties can also satisfy a long-standing need for materials, for example textile or packaging materials, which could easily be rendered flame-retardant by applying a flame and heat resistant coating thereto, or by impregnation.

The invention relates to a method for producing a suspension of thermally exfoliated vermiculite, comprising the following steps: a) thermal exfoliation of vermiculite by: i) heating the vermiculite in an oven at a temperature in the range of 300-1200°C for 1- 5 seconds; ii) cooling the thermally exfoliated vermiculite heated in step i) to a temperature below 100°C in an air stream to produce thermally exfoliated vermiculite; b) wet grinding the thermally exfoliated vermiculite obtained in step a) in a dispersion medium to obtain a suspension with the desired concentration of vermiculite. The dispersion medium may be an aqueous solution, including an alkali silicate solution, or water. In a preferred embodiment, when the dispersion medium is water, the extinguishing agent contains a stabilizing agent. Depending on the proportion of the components of the suspension itself, by increasing the % proportion (by weight) of vermiculite or by introducing additional components into the suspension, the suspension prepared by the above method may take the form of a stable vermiculite paste. To obtain the stable paste, ground vermiculite with water-glass should be allowed to thicken (1 to several days). Thereafter, the paste may be diluted to a stable suspension. The step of wet milling in a specific dispersion medium with the use of a disperser allows to obtain a stable suspension, which has not been possible so far by methods known in the art. Dry milling of the vermiculite did not produce a stable slurry that would remain stable for more than a few days. Similarly, dry grinding of vermiculite followed by mixing it with aqueous solutions such as water glass or water also did not produce a stable suspension that would remain stable for more than a few days. In these two cases, separation of the resulting suspension was observed already within 24 hours. Without being bound by any theory, dry milling, or wet milling, but without the use of a suitable disperser, probably makes it impossible to obtain a stable suspension due to the structure of vermiculite, with a significant amount of air between the pores, and due to the insufficient parameters of the disperser, which prevent the vermiculite flakes to break under high pressure.

In a preferred embodiment, the method comprises the additional step of c) mixing the suspension obtained in step b) with a stabilizing agent and with an additional dispersion medium or water to obtain a vermiculite-containing suspension of the desired density.

Preferably, the dispersion medium is an alkali silicate solution, preferably water glass, more preferably sodium water glass. In another embodiment, the dispersion medium may also be water to obtain a suspension with an increased vermiculite content.

A stable suspension of vermiculite on a production scale was obtained using a disperser (NETZSCH Epsilon 30 in-line disperser). In one embodiment, a stable suspension was obtained by grinding vermiculite with water, which was not possible under laboratory conditions. In another embodiment, a stable suspension was obtained by grinding thermally exfoliated vermiculite, ground with water and stabilizing additives.

Preferably, heating of the vermiculite is carried out in an oven at a temperature ranging from 550°C to 750°C for 2-4 seconds. In the preferred method of the invention, the temperature of the thermally exfoliated vermiculite at the exit of the oven is not greater than 300 °C, preferably in the range of 230 to 280 °C.

In a preferred method of the invention, the vermiculite in the sub-step ii) is cooled in a stream of air at a temperature in the range of 15 to 25°C.

Also preferably, additional dispersants, stabilizers, preservatives, flame retardants and pigments are added to the suspension obtained in step b) or the suspension obtained in step c). More preferably, the stabilizers are selected from acrylic stabilizers, silicones, polysaccharides, cellulose derivatives, polymers, phyllosilicate-based thickeners, and resins. Exemplary stabilizers are those selected from the group consisting of modified starch, xanthan gum, guar gum, and locust bean gum, or methylcellulose. In a further embodiment, the stabilizer is xanthan gum or methyl cellulose.

The invention also relates to a suspension containing thermally exfoliated vermiculite obtained by the above method.

In addition, the present invention relates to an extinguishing agent containing thermally exfoliated vermiculite suspended in a solution of alkali silicates, wherein vermiculite constitutes from 4 to 70% of the dispersion, a solution of alkali silicates constitutes from 20 to 95 % of the dispersion, where vermiculite constitutes from 8 to 18 % of the dispersion, preferably from 10 to 15 % of the dispersion, the solution of alkali silicate constitutes from 60 to 92 % of the dispersion, preferably from 80 to 90 % of the dispersion.

In a preferred embodiment of the invention, the extinguishing agent additionally comprises stabilizing agents constituting up to 3 % of the dispersion, preferably up to 1 % of the dispersion.

Also preferably, the extinguishing agent comprises the thermally exfoliated vermiculite with particle sizes in the range of 1 to 1000 pm, preferably in the range of 30 to 600 pm, more preferably 50 to 300 pm.

Preferably, the density of the extinguishing agent is from 1.08 to 1.5 kg/m ³ , preferably from 1.15 to 1.40 kg/m ³ .

In a preferred embodiment of the invention, the solution of alkali silicates comprises a silicic acid sodium salt solution or a silicic acid potassium salt solution. More preferably, the solution of alkali silicates is a silicic acid sodium salt solution and a silicic acid potassium salt solution in a weight ratio of from 90 %:10 % to 10 %:90 %, preferably 50 %:50 %. Alternatively, the solution of alkali silicates is a silicic acid sodium salt solution. Also preferably, the extinguishing agent is based on a suspension of the thermally exfoliated vermiculite obtained by the method of the invention, or the suspension according to the invention.

The present invention further provides an extinguishing agent comprising thermally exfoliated vermiculite suspended in a solution of alkali silicates, where the vermiculite constitutes from 4 to 70 % of the dispersion, the solution of alkali silicates constitutes from 20 to 95 % of the dispersion, and flame-retardant additives constitute up to 10 % of the dispersion.

Preferably, the vermiculite constitutes from 8 to 22 % of the dispersion, preferably from 10 to 20 % of the dispersion, the solution of alkali silicates constitutes from 65 to 95 % of the dispersion, preferably from 70 to 90 % of the dispersion, and the flame-retardant additives constitute up to 6 % of the dispersion, preferably up to 4 % dispersion.

In a preferred embodiment of the invention, the flame-retardant additives comprise agents based on aluminum hydroxide, magnesium hydroxide, metakaolin, zeolite, melamine, melamine polyphosphate, ammonium polyphosphate, pentaerythritol, encapsulating agents and salt additives, more preferably the flame-retardant additives comprise agents based on ammonium polyphosphate, metakaolin, zeolite, encapsulating agents and salt additives, most preferably flame-retardant additives comprise metakaolin, zeolite, sodium chloride, potassium chloride, potassium carbonate, sodium sulfate, sodium bicarbonate or a mixture thereof.

Also preferably, the extinguishing agent comprises stabilizing agents constituting up to 6 % of the dispersion, preferably up to 5 % of the dispersion, most preferably up to 4 % of the dispersion.

Preferably, the extinguishing agent comprises thermally exfoliated vermiculite with particle sizes in the range of 1 to 1000 pm, preferably in the range of 30 to 600 pm, more preferably 50 to 300 pm.

Also preferably, the density of the extinguishing agent is from 1.08 to 1.5 kg/m ³ , preferably from 1.15 to 1.40 kg/m ³ .

In a preferred embodiment of the invention, the solution of alkali silicates comprises a silicic acid sodium salt solution or a silicic acid potassium salt solution. More preferably, the solution of alkali silicates is a silicic acid sodium salt solution and a silicic acid potassium salt solution in a weight ratio of from 90 %:10 % to 10 %:90 %, preferably 50 %:50 %. Alternatively, the solution of alkali silicates is a silicic acid sodium salt solution. Preferably, the extinguishing agent is based on a suspension of the thermally exfoliated vermiculite obtained by the method according to the invention, or the suspension according to the invention.

Also preferably, the electrical appliances are live electrical appliances, preferably lithium-ion accumulators and batteries.

The present invention relates also to an agent for extinguishing photovoltaic panels comprising thermally exfoliated vermiculite suspended in a solution of alkali silicates, wherein the vermiculite constitutes from 4 to 70 % of the dispersion, the solution of alkali silicates constitutes from 20 to 95 % of the dispersion, and pigments constitute up to 20 % of the dispersion, wherein the vermiculite constitutes from 8 to 25 % of the dispersion, preferably from 10 to 20 % of the dispersion, the solution of alkali silicates constitutes from 40 to 92 % of the dispersion, preferably from 60 to 80 % of the dispersion, and the pigments constitute up to 17 % of the dispersion, preferably up to 15 % of the dispersion.

In a preferred embodiment of the invention, the pigments comprise black pigments, black carbon pigment, hematite, spinel, rutile pigments, preferably the pigments comprise black carbon pigment, hematite and spinel pigments or a mixture thereof, more preferably the pigments include carbon black and hematite pigments or a mixture thereof.

In an equally preferred embodiment of the invention, the extinguishing agent for photovoltaic panels additionally comprises stabilizing agents constituting up to 5 % of the dispersion, preferably up to 3 % of the dispersion.

Also preferably, the extinguishing agent for photovoltaic panels comprises thermally exfoliated vermiculite with a particle size in the range of 1 to 1000 pm, preferably in the range of 30 to 600 pm, more preferably 50 to 300 pm.

Preferably, the density of the extinguishing agent for photovoltaic panels is from 1.08 to 1.5 kg/m ³ , preferably from 1.15 to 1.40 kg/m ³ .

In a preferred embodiment of the invention, the solution of alkali silicates comprises a silicic acid sodium salt solution or a silicic acid potassium salt solution. Preferably, the solution of alkali silicates is a silicic acid sodium salt solution and a silicic acid potassium salt solution in a weight ratio of from 90 %: 10 % to 10 %:90 %, preferably 50 %:50 %. Alternatively, the solution of alkali silicates is a silicic acid sodium salt solution.

Also preferably, the extinguishing agent for photovoltaic panels is made on the basis of a suspension of the thermally exfoliated vermiculite obtained by the method according to the invention, or the suspension according to the invention. The invention relates also to a deactivating agent for photovoltaic panels containing thermally exfoliated vermiculite suspended in a solution of alkali silicates, wherein the vermiculite constitutes from 4 to 70 % of the dispersion, the solution of alkali silicates constitutes from 20 to 95 % of the dispersion, and pigments constitute up to 20 % of the dispersion. More preferably, the vermiculite constitutes from 8 to 25 % of the dispersion, preferably from 10 to 20 % of the dispersion, the solution of alkali silicates constitutes from 40 to 92 % of the dispersion, preferably from 60 to 80 % of the dispersion, and pigments constitute up to 17 % of the dispersion, preferably up to 15 % of the dispersion.

In a preferred embodiment of the invention, the pigments comprise black pigments, black carbon pigment, titanium dioxide pigments, iron oxide-based pigments, preferably the pigments comprise the black carbon pigment and iron oxide-based pigments, or a mixture thereof, more preferably the pigments comprise carbon black and the iron oxide-based pigments, or a mixture thereof.

Also preferably, the deactivating agent for photovoltaic panels additionally comprises stabilizing agents constituting up to 5 % of the dispersion, preferably up to 3 % of the dispersion.

In a preferred embodiment of the invention, the deactivating agent for photovoltaic panels comprises the thermally exfoliated vermiculite with particle sizes in the range of 1 to 1000 pm, preferably in the range of 30 to 600 pm, more preferably 50 to 300 pm.

Preferably, the density of the extinguishing agent for photovoltaic panels is from 1.08 to 1.5 kg/m ³ , preferably from 1.15 to 1.40 kg/m ³ .

In a preferred embodiment of the invention, the solution of alkali silicates comprises a silicic acid sodium salt solution or silicic acid potassium salt solution. Preferably, the solution of alkali silicates is a silicic acid sodium salt solution and a silicic acid potassium salt solution in a weight ratio of from 90 %: 10 % to 10 %:90 %, preferably 50 %:50 %. Alternatively, the solution of alkali silicates is a silicic acid sodium salt solution.

Also preferably, the extinguishing agent is made on the basis of a suspension of the thermally exfoliated vermiculite obtained by the method of the invention, or the suspension according to the invention.

The invention relates also to a passive fire protection agent comprising thermally exfoliated vermiculite suspended in a solution of alkali silicates, wherein the vermiculite constitutes from 4 to 70 % of the dispersion, and the solution of alkali silicates constitutes from 20 to 95 % of the dispersion. Preferably, the vermiculite constitutes from 8 to 18 % of the dispersion, preferably from 10 to 15 % of the dispersion, the solution of alkali silicates constitutes from 60 to 92 % of the dispersion, preferably from 80 to 90 % of the dispersion.

In a preferred embodiment of the invention, the passive fire protection agent additionally comprises stabilizing agents constituting up to 3 % of the dispersion, preferably the stabilizing agents constituting up to 1 % of the dispersion.

Also preferably, the passive fire protection agent comprises thermally exfoliated vermiculite with a particle size in the range of from 1 to 1000 pm, preferably in the range of from 30 to 600 pm, more preferably from 50 to 300 pm.

Preferably, the density of the passive fire protection agent is from 1.08 to 1.5 kg/m ³ , preferably from 1.15 to 1.40 kg/m ³ .

In a preferred embodiment of the invention, the solution of alkali silicates comprises a silicic acid sodium salt solution or a silicic acid potassium salt solution. Preferably, the solution of alkali silicates is a silicic acid sodium salt solution and a silicic acid potassium salt solution in a weight ratio of from 90 %: 10 % to 10 %:90 %, preferably 50 %:50 %. Alternatively, the solution of alkali silicates is a silicic acid sodium salt solution.

Also preferably, the extinguishing agent is made on the basis of a suspension of the thermally exfoliated vermiculite obtained by the method of the invention, or the suspension according to the invention.

The present invention also relates to use of the extinguishing agent according to the invention for extinguishing a fire. Preferably, to use for extinguishing solids, solid objects, preferably appliances, wood, chemical materials, batteries and accumulators. More preferably, the accumulators and batteries are lithium-ion accumulators, lithium batteries and lithium-ion batteries. Alternatively, the appliances are electrical appliances, more preferably live electrical appliances, most preferably electrical appliances under voltage up to 1000 V.

The present invention relates also to use of the extinguishing agents according to the invention for extinguishing photovoltaic panels.

The present invention relates also to use of the extinguishing agent according to the invention for deactivating photovoltaic panels.

The present invention relates to use of a passive fire protection agent according to the invention for coating, gluing or impregnating surfaces to increase their fire resistance, preferably in products used in the transport and storage of hazardous materials. Preferably, to use for fire prevention of lithium or lithium-ion batteries and accumulators. Alternatively, to use for the production of protective materials, preferably flame-retardant paints, flame-retardant packaging and fire blankets, either as a binder and/or heat resistant adhesive. The invention relates also to an extinguishing appliance comprising the extinguishing agents according to the invention, the deactivating agent according to the invention or the passive fire protection agent according to the invention.

The invention relates also to extinguishing modules, including extinguishing units, installed on rescue and fire protection vehicles, comprising the extinguishing agents according to the invention, the deactivating agent according to the invention or the passive fire protection agent according to the invention for extinguishing heavy fires (including electric cars).

The invention relates also to an extinguisher containing the extinguishing agent according to the invention.

The present invention meets the long-standing need to provide extinguishing agents, including stable extinguishing and/or deactivating agents for photovoltaic panels, as well as refractory coatings and impregnants free from prior art drawbacks and problems, by providing a stable suspension of thermally exfoliated vermiculite, and thus an ecological agent, not affecting and not permanently changing the environment, in particular the natural environment exposed to such an agent. In addition, by generating a stable dispersion, the suspension of thermally exfoliated vermiculite can be used not only as an extinguishing agent, used for active fire extinguishing, including for extinguishing fires of photovoltaic panels, but also for fire prevention and rendering fire resistance by coating and/or impregnating various types of articles (e.g. in particular packaging materials such as cardboard packings, plastic surfaces, textile materials or non-woven fabrics). The stable suspension of the thermally exfoliated vermiculite obtained by the method of the invention is a suitable agent for coating accumulators, lithium or lithium-ion batteries, etc., to increase their fire safety, but it can also be used for the production of non-flammable packings, non-flammable paints or fire blankets. Due to its favourable properties, the stable suspension of thermally exfoliated vermiculite according to the present invention is also used in the transport and storage of hazardous materials exposed to high temperatures. The stable suspension of the thermally exfoliated vermiculite obtained by the method of the invention can also be used as an extinguishing agent for extinguishing fires in an active manner, by stopping the combustion process in the fire zone, where it is introduced by means of fire extinguishers, fixed, portable or mobile fire extinguishing appliances or installations. In addition, the stable suspension of thermally exfoliated vermiculite can be used as a passive fire protection agent and applied to a surface by spray, roller, brush, hose, or otherwise, or used to impregnate materials to provide heat and flame insulating product.

Moreover, the stable suspension of the thermally exfoliated vermiculite obtained by the method according to the invention is used in extinguishing photovoltaic panels. Further, the addition of a pigment to the present suspension stops the electricity generation process, allowing the photovoltaic panel to be effectively deactivated, turned off and effectively extinguished if necessary. A deactivated photovoltaic panel can be reused after washing off the deactivating agent from its surface. Moreover, the addition of flame-retardants to the present slurry and extinguishing agent enables even safer, more effective and faster fire extinguishing.

The present invention is explained in more detail below, with reference to the drawings, in which:

Fig. 1 is a scanning microscope photograph illustrating thermally exfoliated vermiculite prior to milling. DLO is the length of the first accordion pleat L=3.871 mm, DL1 means the width of the first accordion pleat L=1.142 mm, DL2 means the width of the second accordion pleat L=0.601 mm;

Fig. 2 is a scanning microscope photograph illustrating thermally exfoliated vermiculite prior to milling, where DLO is the width of the first accordion pleat L=0.615 mm, DL1 is the width of the second accordion pleat L=1.345 mm;

Fig. 3, on the other hand, shows dry-milled thermally exfoliated vermiculite using standard ball mill grinding;

Fig. 4 illustrates thermally exfoliated vermiculite wet-milled in a liquid medium - water, in a corundum mill. Clear delamination is visible, which indicates the instability of the extinguishing agent and the precipitation of vermiculite;

Fig. 5 shows dry-milled thermally exfoliated vermiculite, where water glass is added in successive stages of obtaining the extinguishing agent. Clear delamination is visible, which indicates the instability of the extinguishing agent and the precipitation of vermiculite;

Fig. 6 illustrates thermally exfoliated vermiculite wet milled in a water glass solution as a stable dispersion;

Figs. 7 and 8 illustrate the formation of a dense layer of a mixture of vermiculite and polymerized silicic acids on an extinguished surface.

Fig. 9 illustrates the formation of a uniform and dense layer of a mixture of vermiculite, polymerized silicic acids and a pigment on a photovoltaic panel.

Fig. 10, panels A and B, illustrate washing of solar panels with pressurized water approximately 30 minutes after application of the agent.

Fig. 11, panels A and B, show cleaning of a dried, flaking layer of a mixture of vermiculite, polymerized silicic acids and a pigment on a deactivated smooth plastic surface applied approximately 20 hours earlier. The method for producing a stable suspension of thermally exfoliated vermiculite according to the invention enables obtaining a stable extinguishing agent containing thermally exfoliated vermiculite with a specific particle size and shape (thin and flat flakes), and also with a mineral bulk density enabling obtaining a stable dispersion and, due to no need to use additional chemicals, reducing environmental pollution.

In addition, exfoliation of vermiculite by the high-temperature thermal treatment at a temperature ranging from 300 to 1200 °C, more preferably at a temperature ranging from 550- 750 °C, causes the increase in the vermiculite volume of 10-15 times, the vermiculite taking the form of swollen, mineral accordion pleats. In this process, thermal exfoliation of vermiculite occurs as a result of the release of water from the raw material through rapid evaporation, which in turn causes a significant increase in its volume. The thermal exfoliation process following the shock heating of vermiculite by electric heaters located in the exfoliating modules allows to obtain vermiculite with a loose, friable and porous structure. The vermiculite produced in this way is characterized by a layer structure which is stable, durable and unchanging over time, i.e., it does not age or degrade. It may be successfully used in the production process of a stable extinguishing agent or a passive fire protection agent, as a light mineral filler forming a dispersion with fireproof and insulating properties.

The term “extinguishing agent” in this description means an agent used to actively extinguish fires, used in fire extinguishers, extinguishing appliances or systems, including fires of batteries, lithium or lithium-ion accumulators, photovoltaic panels, live electrical equipment up to 1000 V. The extinguishing agent may also contain additives to reduce flammability. The addition of a flame retardant to the extinguishing agent increases the effectiveness of extinguishing large fires: battery packs and photovoltaic panels, energy storage means, high- power accumulators (e.g. of electric vehicles) or large electrical appliances up to 1000 V. The extinguishing agent may also contain additives such as pigments. Liquid or powdery pigments may be directly added at the steps of wet grinding the thermally exfoliated vermiculite or mixing the resulting suspension, or the extinguishing agent.

In this specification, the term “extinguishing agent for photovoltaic panels” means an agent used to coat the photovoltaic panels to actively extinguish a fire.

The term “deactivating agent for photovoltaic panels” means an agent used to coat photovoltaic panels in order to deactivate them by coating their surface with a light blocking agent and/or a light blocking cover forming agent, which, after cleaning and/or washing, allows further operation of the panel. In this specification, the term “extinguishing and deactivating agent for photovoltaic panels” means an agent used to coat photovoltaic panels in order to disable them by coating the surface with a light blocking agent and/or a light blocking cover forming agent, e.g., with a pigment added, and simultaneously used as an extinguishing agent to actively extinguish a fire.

Moreover, the term “extinguishing agent with added flame retardants” refers to such an extinguishing agent that contains additives, called flame retardants, which facilitate extinguishing and prevent the ignition of the material after the fire is extinguished, and improve the extinguishing efficiency.

The term “passive fire protecting agent”, as used herein, means an agent used to coat, fill or impregnate articles to render them resistant to fire and high temperatures.

In order to produce a stable suspension of the thermally exfoliated vermiculite according to the present invention with the desired extinguishing and fire retardant properties as described above, vermiculite is first subjected to thermal treatment at a temperature ranging from 300 to 1200 °C, followed by rapid cooling, preferably in a stream of air at temperature in the range of from 15 to 25 °C, then it is wet-ground in a dispersion medium with the addition of water glass (also referred to as glass water), i.e. wet grinding in a solution of alkali silicates. The present inventors surprisingly found that the use of the method described above makes it possible to obtain a suspension characterized by exceptional extinguishing properties, such as e.g., the effectiveness of active and passive extinguishing and excellent dispersion stability, and after adding a pigment, obtaining a stable suspension for deactivating and/or extinguishing photovoltaic panels. The dispersion medium for wet milling can also be water. Then, a suspension with an increased content of vermiculite is obtained. When producing industrial samples on the production line (NETZSCH Epsilon 30 in-line disperser), a stable suspension was obtained by grinding vermiculite with water, which was not possible in laboratory conditions or which was not possible by mixing thermally exfoliated dry-ground vermiculite with water and stabilizing additives.

The term „ water glass” or „glass water” as used herein means aqueous solutions of alkali silicates. Examples of water glass include sodium, potassium water glasses, and mixtures thereof.

Wet grinding, i.e., with the addition of an aqueous solution of sodium silicates (so-called water glass), of thermally exfoliated vermiculite unexpectedly enables stabilization of crushed vermiculite in suspension and obtaining an extinguishing agent containing thermally exfoliated vermiculite with desired properties, which can also be used as a passive fire protection agent. Thus, the process according to the invention ensures the production of thermally exfoliated vermiculite with a constant particle size in the range of from 1 to 1000 pm, preferably from 30 to 600 pm, more preferably from 50 to 300 pm, which in turn makes it possible to increase the efficiency of the milling process and obtain a stable suspension or paste of vermiculite from a natural, environmentally friendly starting material, as a final product. In the subsequent steps of the present method, a stable dispersion of thermally expanded vermiculite containing 4 to 70 % of vermiculite is obtained on the basis of a stable vermiculite suspension or paste.

The terms “suspension” and “dispersion” are used interchangeably herein and mean a system consisting of at least two phases, at least one of which is a particulate solid (according to the invention, thermally comminuted exfoliated vermiculite) dispersed in a second continuous phase (according to the invention, in an alkali silicate aqueous solution or water), called the dispersion medium or the dispersing phase. In addition, the terms “suspension” and “dispersion” also refer to a thick pasty suspension suspended in a dispersion medium, as well as to a suspension dispersed in a larger amount of a dispersion medium.

In order to increase the surface adhesion of the agent obtained by the method according to the invention, including the adhesion to smooth or metal surfaces, rendering it thixotropic and pseudoplastic properties, increasing the microbiological and physical stability, and effectiveness, it may also contain other additives, such as stabilizers, dispersants and preservatives.

Preferably, the stabilizers are acrylic stabilizers, cellulose derivatives (e.g., hydroxy ethyl cellulose, methyl cellulose), polysaccharides (e.g., modified starch, xanthan gum, guar gum, locust bean gum), polymers (e.g., an aqueous acrylic polymer sodium salt solution), thickeners based on phyllosilicates, silicones, resins, preferably the dispersants are anionic, cationic or non-ionic surfactants, modified acrylic, ethylene, propylene copolymers, e.g. ammonium or sodium salts of polyacrylic acid, an aqueous solution of salts of modified phosphoric acid, and the preservatives are preferably various biocides or benzisothiazolinone derivatives.

The extinguishing agent obtained by the method according to the invention is an agent with a high density ranging from 1.08 to 1.5 kg/m ³ , which enables formation of an even, stable and dense coating on the area spread over by a fire, thanks to which it is possible to effectively retain the extinguishing agent on all fire-affected surfaces, including smooth and metal surfaces. This phenomenon is ensured by the strong adhesion of the agent produced according to the invention to various surfaces, regardless of their type and character, and by reducing the rate of evaporation of the extinguishing agent. This, in turn, is directly related to the reduction of its consumption. At the same time, the obtained extinguishing agent is so fluid that it is possible to easily spray a stream of the extinguishing agent obtained by the method according to the invention over a distance of even more than 5 meters, while obtaining an even coverage of the area spread over by a fire, pumping or spraying the extinguishing agent on a given surface and effective removing the extinguishing agent from the container (e.g. from a fire extinguisher, portable and mobile fire extinguishing appliances, extinguishing modules, including fire extinguishing units, including those installed on rescue and fire extinguishing vehicles). Moreover, the extinguishing agent remaining in the extinguisher makes less than 8 % of the initial amount of extinguishing agent, and thus the extinguishing agent according to the invention is almost completely released from the extinguisher.

Further, the extinguishing agent according to the present invention provides effective fire extinguishing, as a result of which a dense layer of a mixture of vermiculite and polymerized silicic acids is formed on the extinguished surface by rapid evaporation of the liquid. Such a layer effectively cuts off the access of oxygen, reduces evaporation of the extinguishing agent. The comminuted vermiculite remaining on the burning surface significantly accelerates the extinguishing process and makes it more effective, and thus reduces spreading and re-ignition of the fire. Extinguishing agents containing the thermally exfoliated vermiculite enable effective extinguishing of fires with less extinguishing agent consumption, in particular effective extinguishing of fires belonging to group A, i.e., fires of solid materials, which normally burn with the formation of glowing coals, e.g., wood, paper, fabrics, etc., including fires of lithium or lithium-ion accumulators and batteries. Due to its properties, the extinguishing agent according to the invention can be used to extinguish fires of appliances under voltage, which can be up to 1000 volts.

In contrast to the water glass-based extinguishing agents known from the prior art, used, for example, to extinguish fires of lithium-ion accumulators and batteries, the method according to the invention surprisingly provides a stable dispersion that is convenient to store or transport to the place of use. The classical dispersion, known from the prior art, obtained by adding dry ground vermiculite to a water glass solution is, by contrast, unstable over time, and in particular during storage the dispersion separates into layers, as shown in the comparative examples below.

It is also worth emphasizing that the solutions of the present invention based on a stable suspension of the thermally exfoliated vermiculite, in particular the extinguishing agent and deactivating agent according to the invention, are fully ecological, and their use does not involve releasing of any harmful chemical compounds into the environment. Thus, it also does not affect the user himself and people in the vicinity of his operation. Moreover, the very process of producing a stable vermiculite suspension is ecological, because instead of a chemical expansion process, a physical process (heating) is employed to delaminate the vermiculite.

The extinguishing agent containing the thermally exfoliated vermiculite according to the invention is characterized by unique extinguishing properties, obtained by producing the high-quality thermally exfoliated vermiculite, and then grinding the vermiculite in an aqueous solution, e.g. a water glass solution or water, which ensures obtaining a stable suspension with specific properties, suitable for storage without change of properties for a long time, i.e. for at least 12 months at room temperature, preferably for 18 months at room temperature, more preferably for 24 months at room temperature. During storage, releasing a liquid from the surface of the extinguishing agent in the range of up to 5 % of the dispersion is permissible.

Examples

Example 1. Method for obtaining the thermally exfoliated vermiculite

The method of exfoliating vermiculite is a result of high-temperature shock treatment of a vermiculite concentrate in electric ovens.

The ovens are combined into one production line that ensures a continuous supply of raw materials, with the possibility of adjusting the speed of feeding the vermiculite concentrate to the oven and the exfoliation temperature, rapid cooling and packaging of the finished thermally exfoliated vermiculite.

By means of automation systems used in the production line, it was possible to smoothly regulate the temperature of the ovens, in steps of 1°C. The smooth temperature control along with the control of the feeding rate of vermiculite to the oven allows for obtaining the optimal quality of the thermally exfoliated vermiculite, depending on the granulation of the vermiculite concentrate and its country of origin (Table 1). The vermiculite exfoliation process takes place at a temperature ranging from 300 to 1200 °C, preferably at a temperature ranging from 550- 750 °C, depending on the granulation of the raw material and its place of origin.

In the first step, the vermiculite concentrate is fed by means of conveyors to the oven preheated to the optimum required temperature. The residence time of the concentrate in the oven is from 1 to 5 seconds, preferably from 2 to 4 seconds. The temperature of the thermally exfoliated vermiculite at the exit from the oven is no more than 300 °C, preferably in the range of from 230 to 280 °C. Then, the vermiculite is rapidly cooled in a stream of air at a temperature ranging from 15 to 25 °C to a temperature below 100 °C. The cooling time of the vermiculite in the production line on conveyor belts is from 30 to 40 seconds. As a result, the thermally exfoliated vermiculite is obtained with a temperature lowered to 30-80 °C, preferably to 30-50 °C.

Surprisingly, it was shown that rapid cooling of the exfoliated vermiculite to a temperature below 100 °C contributes to the reduction of its brittleness and ensures its homogeneity. Cooling the conveyor belts, on which the vermiculite falls after leaving the kiln, by circulating cold water supplied to hermetically sealed conveyors, did not allow for obtaining the desired effect due to the porous structure of the vermiculite. Accordingly, it has been found that the most effective rapid cooling of the thermally exfoliated vermiculite is achieved by flowing cold air and using extended conveyor belts to extend the duration of air flow over the already thermally exfoliated vermiculite.

Subsequently, the cooled vermiculite is subjected to the next technological steps or it is packed and stored for further use.

The thermally exfoliated vermiculite obtained thereby (Figs. 1 and 2) is characterized by optimal density, uniformity and the ability to maintain its porous structure during further use or processing.

The parameters of the exemplary thermally exfoliated vermiculite are shown below:

The bulk density of the vermiculite used to prepare the agent according to the invention is from 80 to 200 kg/m ³ , preferably from 90 to 190 kg/m ³ , more preferably from 100 to 180 kg/m ³ To confirm the properties of the thermally exfoliated vermiculite, the analyses presented below were carried out.

Table 1. Characteristics of the concentrates and the obtained thermally exfoliated vermiculite

Example 2. Method for obtaining the extinguishing agent containing the thermally exfoliated vermiculite suspended in the water glass solution

After obtaining the thermally exfoliated vermiculite, the resulting vermiculite was dry- and wet-milled in a ball mill, a corundum mill and a continuous disperser (NETZSCH Epsilon 30 in-line disperser) (Table 2). Non-limiting examples of continuous dispersers are flow dispersers (e.g., commercially available from IKA) or emulsion and suspension dispersers (e.g., commercially available from VEKAMAF).

Only the wet grinding in the presence of alkali silicates in a continuous disperser (NETZSCH Epsilon 30 in-line disperser) allowed for obtaining a stable mineral paste with a vermiculite particle size ranging from 1 to 1000 pm, preferably from 30 to 600 pm, more preferably from 50 to 300 pm.

Example 3. Method for obtaining the extinguishing agent containing the thermally exfoliated vermiculite suspended in water

After obtaining the thermally exfoliated vermiculite, the resulting vermiculite was dry- and wet-milled in a ball mill, a corundum mill and a continuous disperser (NETZSCH Epsilon 30 in-line disperser) (Table 2). Non-limiting examples of continuous dispersers are flow dispersers (e.g. commercially available from IKA) or emulsion and suspension dispersers (e.g. commercially available from VEKAMAF).

As in the case of wet grinding in the presence of alkali silicates, grinding in the presence of water in a continuous disperser (NETZSCH Epsilon 30 in-line disperser) allowed for obtaining ground vermiculite with particle sizes ranging from 1 to 1000 pm, preferably from 30 to 600 pm, more preferably from 50 to 300 pm. Then, in the subsequent steps, we obtain a stable suspension by adding stabilizing additives and/or water glass. Usually, the dry or wet process of grinding the minerals is carried out using mills in the presence of water. Standard vermiculite grinding methods are not free from disadvantages such as grinding heterogeneity, high energy consumption, or obtaining an unstable product. In addition, dry grinding of thermally exfoliated vermiculite or wet grinding of thermally exfoliated vermiculite using standard mills with water, adding water, water glass or stabilizing additives to the ground vermiculite at further steps lead to an unstable suspension, its delamination, and separation of the ground vermiculite (Figs. 3-6).

Table 2

Surprisingly, variants 6, 7 and 8 resulted in a stable suspension of crushed vermiculite with water glass or water. In variants 6, 7 and 8, thermally exfoliated vermiculite particles are introduced under reduced pressure into the stream of a fluid, which allows for high wettability of particles (-0.1 bar), and the grinding process itself takes place at increased pressure (4.3-4.7 bar). The best result was achieved using the NETZSCH Epsilon 30 in-line disperser. Examples of technological process parameters are shown in Table 3. Depending on the desired grinding quality, which depends on the particle size and vermiculite concentration, we have the following technological process parameters. As the % vermiculite content increases, it is possible to extend the grinding time period. The % of the composition or suspension indicated herein refer to % by weight.

Table 3

Changing the parameters of pressure, duration and speed of rotation in the grinding process leads to obtaining an unstable slurry of poor quality, which later use in the production of a stable extinguishing agent whose stability would be maintained for a long time, is difficult to achieve. In addition, it has been shown that grinding thermally exfoliated vermiculite under high pressure with the use of a disperser allows the dispersion medium (water glass or water) to be forced into the micropores of the vermiculite, which enables its grounding to the desired size to obtain a stable suspension.

Considering the above, obtaining a stable extinguishing product containing the thermally exfoliated vermiculite is achieved by selecting the appropriate quality of a raw material, type of vermiculite processing, type of equipment (NETZSCH Epsilon in-line disperser), dispersion properties of the medium, order of introducing ingredients (importantly, introducing ingredients during grinding or in the subsequent steps) or by adding stabilizing additives.

The method according to the invention, comprising the steps of grinding and mixing in a continuous disperser the thermally exfoliated vermiculite in a solution of sodium silicates or water, or a mixture thereof, already in one technological process, makes it possible to ensure the most favorable properties of the extinguishing agent based on the thermally exfoliated vermiculite, such as additional comminuting of the thermally exfoliated vermiculite particles, obtaining particles of similar sizes, treatment of vermiculite particles with a silicate solution, penetration of silicates or water into the micropores of the vermiculite particles, obtaining a stable mineral suspension, creating a stable composition that has a unique effect when extinguishing fires of various types of materials by creating a dense layer of a vermiculite and polymerized silicic acids mixture.

Without being bound by any theory, due to the fact that the thermally exfoliated vermiculite has a porous structure, the silicate solution or water covers the surface during the grinding of vermiculite and penetrates micropores of the vermiculite particles, and the quality of the resulting suspension depends on the type of water glass.

Table 4 Characteristics of the obtained paste from crushed vermiculite depending on the type of water glass

By use of sodium glass (Table 4) with the SiO ₂ content ranging from 6 to 40 %, preferably from 15 to 35 %, more preferably 20 - 25 %, in the wet-grinding process of the thermally exfoliated vermiculite, a homogeneous, stable suspension, and on its basis a stable dispersion containing a solution of silicates constituting from 20 to 95 % of the dispersion, preferably from 60 to 92 %, were obtained. The use of a potassium glass extends the grinding process and allows for obtaining a very dense extinguishing agent. The use of the potassium glass does not enable fine grinding of vermiculite - a very thick paste with large heterogeneous vermiculite particles is obtained. By extending the powdering time, the dispersant exceeds safe operating parameters (overheats and shuts down, engine overload). Preferably, the wet grinding is carried out in a solution of sodium water glass.

Vermiculite reacts with water glass to form a thick slurry. To increase the vermiculite content in the extinguishing agent, the water glass should be diluted with water beforehand, or the thermally exfoliated vermiculite is ground with water. What was a surprise for the inventors, only in the case of grinding the thermally exfoliated vermiculite in a dispersant, a stable suspension of vermiculite was obtained. Also in industrial production on the production line, it was possible to obtain a stable suspension by grinding vermiculite with water, which was not possible in laboratory conditions.

A stable extinguishing agent is produced by dispersing the resulting suspension of vermiculite in a liquid, preferably in a solution of silicates or water, using any device that ensures obtaining a homogeneous stable suspension, for example a container with a stirrer, or a disperser, or an industrial mixer, etc.

In the next step, desired additives for increasing the ability to attach to the surface, additional product stabilization, or compounds increasing the microbiological and physical stability, and the effectiveness of the extinguishing agent, are optionally added. Exemplary stabilizing agents are shown in Table 5.

Table 5

As a result of the method according to the invention, a stable extinguishing agent is obtained containing thermally exfoliated vermiculite constituting from 4 to 70 % of the dispersion, preferably from 8 to 18 % of the dispersion, most preferably 10-15 %, a solution of alkali silicates constituting from 20 to 95 % of the dispersion, preferably from 60 to 92 % of the dispersion, and stabilizing additives constituting less than 3 % of the dispersion, preferably less than 1 % of the dispersion. Comparative characteristics of the extinguishing agent samples obtained, depending on the % content of vermiculite and water glass, are presented in the Tables below.

Table 6 Comparative characteristics of the obtained extinguishing agent samples depending on the % content of vermiculite and water glass Sample 2 is the most effective and stable and has been tested further, e.g. as described in Example 5.

Table 7 Comparative characteristics of the obtained samples depending on the % content of vermiculite and water glass

Samples 8 and 9 were shown to be the most effective and stable. Sample 8 was further tested as described below in the following Examples, concerning i.a., effectiveness or storage. Table 8 Comparative characteristics of the obtained samples depending on the % content of vermiculite and water glass

Sample 11 is the most effective and stable, and was further tested as described below in the following Examples, concerning i.e. effectiveness or storage.

Example 4. Testing the effectiveness of the thermally exfoliated vermiculite suspended in the aqueous sodium silicate solution or water with the additives to increase microbiological and physical stability as the extinguishing agent

To test the effectiveness of the extinguishing agent based on the thermally exfoliated vermiculite, a number of practical tests were carried out, e.g., extinguishing traditional inflammable solids, such as wood. In addition, extinguishing of various types of batteries and accumulators (including lithium and lithium-ion batteries), which were subjected to intense fire and then extinguished, was performed.

The extinguishing agent was applied to the burning surfaces by spraying/atomizing under pressure by means of various modifications of the extinguisher. The following parameters were evaluated: the expelling distance of the extinguishing agent from the fire source, the duration of the extinguishing agent action, the type of the extinguishing agent stream, the type of coverage of extinguished objects, the types of extinguished objects, the types of extinguished fires, the impact on the environment. Then, in each of the variants of the experiment, a wait time of minimum of three minutes was added after the end of the extinguishing phase to ensure that no so-called self-ignition, i.e., internal sources of fire that ignite spontaneously, were created.

The stable extinguishing agent based on the thermally exfoliated vermiculite is so effective that it extinguished the fire immediately after application and no spontaneous ignition occurred in any of the experimental variants, which confirms the surprising properties of the extinguishing agent in question, including the formation of a dense layer of a mixture of vermiculite and polymerized silicic acids (Fig. 7 and 8) on the extinguished surface, that cuts off the access of oxygen to the extinguished objects. In addition, the created layer is sufficiently dense and does not have holes and pores, that prevents flow of oxygen to the burning surface and prevents rapid evaporation of the liquid. For effective extinguishing of e.g., cardboard, it is enough to cover the fire area with a layer less than 1 mm thick.

Example 5. Application of the extinguishing agent based on the thermally exfoliated vermiculite suspended in the aqueous sodium silicate solution or water

Extinguishing flammable solids with the extinguishing agent in question was conducted, and the results are presented in Table 9 below.

Table 9

The extinguishing agent in question finds application for extinguishing solids, solid objects such as wood, chemical materials, especially batteries (including lithium or lithium-ion batteries), i.e., for extinguishing group A fires, including lithium, lithium-ion accumulators and batteries. Moreover, by conducting additional tests at the High Voltage Laboratory of the Institute of Power Engineering, it has been shown that the VER-DIS 6x foam fire extinguisher filled with the above-mentioned extinguishing agent can be used to extinguish power appliances and apparatuses with the rated operating voltage of up to 1 kV inclusive, which are under voltage, due to meeting the requirements of p. 9 of PN-EN 3- 7+Al:2008.

Example 6. Extinguishing agent stability test

Extinguishing agent stability tests were carried out for 6, 12, 18 and 24 months, respectively, and the condition of the preserved samples of the preparation was controlled every month. The samples were stored at room temperature 15-25°C and their stability was evaluated based on the following parameters: the stable suspension, no hard vermiculite deposits at the bottom. After 3 months, extinguishing of the traditional inflammable solids (e.g., cardboard) was performed, and the effectiveness of the extinguishing agent was maintained. After 6 months, the appearance of the samples did not change.

A stress test was also carried out for the extinguishing agent upon storage at limiting temperatures (+5 °C and +60 °C). The samples and their stability were assessed on the basis of the following parameters: the stable suspension, no hard vermiculite deposits at the bottom. During storage, up to 5 % of liquid is released onto the surface of the product.

Table 10 Extinguishing agent stability tests

The above test results indicate the full stability of the extinguishing agent samples in the tested range. Example 7. Comparative tests of the extinguishing agent in relation to the marketed preparations

The following extinguishers, suitable for extinguishing group A fires, were used for comparative tests: a water fog extinguisher, a foam extinguisher. The extinguishing agent based on the thermally exfoliated vermiculite suspended in a water glass solution was placed in a pressure vessel of a portable fire extinguisher, and applied by means of an expelling system (a control valve, hose, outlet nozzle). The following parameters were compared:

- the expelling distance of the extinguishing agent from the fire source, as the distance from the extinguisher nozzle to the farthest range of the expelled extinguishing agent stream;

- the duration of action of the extinguishing agent, calculated on the basis of the requirements of the EN 3-7:2004+Al:2007 standard;

- the type of the extinguishing agent stream (depends on the properties of the agent used);

- the type of coverage of extinguished objects;

- the types of extinguished objects: fires of small lithium-ion batteries (e.g. batteries in mobile phones), fires of solids (wood);

- types of extinguished fires: group A fires, lithium-ion battery fires.

Table 11 Characteristics of extinguishing agents

A set of batteries was placed on a steel tray and ignited in two ways, either by shortcircuiting or by treating the batteries with the flame of a gas burner. After the battery was set on fire, extinguishing began. After the extinguishing, the current flow and the optional possibility of re-ignition of the battery were assessed.

In addition, a small group A fire test (wood pile fire) was carried out.

After carrying out the tests, it was found that the use of vermiculite suspension in a water glass solution or water ensures obtaining a solution with increased viscosity, which does not flow down from the extinguished material as fast as in the case of solutions known from the prior art, in particular in comparison to demineralized water and a foam-producing agent solution. The increased viscosity provides the desired, more favorable adhesion of the solution to burning surfaces (surfaces in the fire area) and thus better insulation - both thermal insulation and cutting off the oxygen supply, which causes the fire to be extinguished.

The use of the stable extinguishing agent based on the thermally exfoliated vermiculite during a fire leads to the formation of a dense layer of a mixture of vermiculite and polymerized silicic acids, or vermiculite, which cuts off the access of oxygen, reduces evaporation of the extinguishing agent and keeps the crushed vermiculite on the burning surface, which significantly accelerates the extinguishing process and makes them more effectively and thus limit the spread and re-ignition of the fire.

In comparative field tests, it was shown that in the present case of the extinguishing agent according to the invention, after the extinguishing process, so-called blue smoke which, if present, is associated with a high probability of re-ignition of unextinguished solid components, was not observed.

In the case of other extinguishing agents known from the prior art used in the tests, such blue smoke was observed, which required to guard the fire and, if necessary, extinguish it. With regard to the tested, commercially available extinguishing agents, the formation of a dense, tight layer covering surface of the burning objects was not observed, that was the case when using the agent according to the present invention.

Such surprising effectiveness of the thermally exfoliated vermiculite suspended in a water glass solution as an extinguishing agent is attained by suspending vermiculite in a solution of silicates, as a result of which a dense layer is formed during the extinguishing process, which allows to cut off oxygen from the fire and the fire source itself. The effectiveness of the thermally exfoliated vermiculite suspended in water as an extinguishing agent is achieved due to the high concentration of vermiculite itself and the addition of flame retardant additives to the extinguishing agent. As a result, a dense layer is formed during the extinguishing process, which cuts off oxygen from the fire and the fire source itself. This makes it possible to avoid self-ignition and there is no need to extinguish items on fire.

Moreover, obtaining the dense layer of a mixture of vermiculite and polymerized silicic acids or the dense layer of highly concentrated vermiculite and flame retardant additives allows for more effective fire extinguishing and lower water consumption, which results in smaller amounts of the extinguishing agent used, limiting damage caused in the vicinity of the fire.

Example 8. Use of the suspension of the thermally exfoliated vermiculite as a passive fire protection agent.

Fire resistance was tested against a fabric impregnated with the fire protection agent and against cardboard, the middle layer of which was impregnated with the fire protection agent. The agent according to the invention was applied by brush. It has been shown that the fabric soaked in the fire protection agent does not burn, and when set on fire, it goes out. A cardboard sample treated with the fire protection agent does not bum, and also when set on fire, it goes out. A 12 cm by 20 cm sample of untreated cardboard burned down completely in 4 minutes 14 seconds.

In addition, the passive fire protection agent was applied to the cardboard layers, which were then superimposed to form a permanent bond. A cardboard sample treated with the fire protection agent acting as a binder does not burn at the places of application, and when set on fire, it goes out. A 12 cm by 20 cm sample of untreated cardboard burned down completely in 4 minutes 14 seconds.

A suspension of thermally exfoliated vermiculite based on the vermiculite according to the invention is also used as a passive fire protection agent, e.g., for coating, gluing or impregnating surfaces in order to increase their fire resistance, in products used in the transport and storage of hazardous materials (e.g. lithium or lithium-ion batteries) or the production of protective materials (non-flammable paints, non-flammable packaging, fire blankets). Example 9. Preparation of the suspension of the thermally exfoliated vermiculite-based extinguishing agent with flame retardant additives

On the basis of the thermally exfoliated vermiculite suspended in an aqueous sodium silicate solution or water with additives to increase microbiological and physical stability, the extinguishing agent with flame retardant additives was developed.

This agent is obtained by adding flame retardant additives to the extinguishing agent in an amount of up to 10 % of the dispersion, more preferably up to 6 % of the dispersion, which allows to obtain an agent for even more effective extinguishing and preventing the ignition of the material after the fire is extinguished.

The extinguishing agent containing flame retardant additives is used, among others, for extinguishing high-capacity electric accumulators, energy storages, electric cars and other live electrical appliances. The addition of flame retardants to the extinguishing agent made on the basis of a suspension of thermally exfoliated vermiculite makes it possible to additionally block spreading of a fire, and thus reduce the flammability of extinguished materials and structures. Flame retardants ensure the creation of a thermal insulation barrier on the surface of the product, thus preventing spreading of a fire, reduce the heating rate of the extinguished structure and reduce the combustion rate.

In one embodiment of the invention, the extinguishing agent with flame retardant additives is used for extinguishing high-capacity electric accumulators and other live appliances.

In one embodiment of the invention, the extinguishing agent with flame retardant additives comprises the flame retardants constituting up to 10 % of the dispersion, more preferably up to 6 % of the dispersion.

The flame retardants comprise, but are not limited to, agents based on aluminum hydroxide, magnesium hydroxide, metakaolin, zeolite, melamine, melamine polyphosphate, ammonium polyphosphate, pentaerythritol, encapsulating agents, and salt additives (for example, sodium chloride, potassium chloride, potassium carbonate, sodium sulfate, sodium bicarbonate or a mixture thereof). In a preferred embodiment of the invention, the flame retardants comprise agents based on metakaolin and zeolite, encapsulating agents (e.g. F-500) and salt additives (sodium chloride, potassium chloride, potassium carbonate, sodium sulfate, sodium bicarbonate or a mixture thereof) (Table 12). Examples of the extinguishing agents for high-capacity electric accumulators and other live appliances based on a suspension of the thermally exfoliated vermiculite are a 1 : 1 mixture of metakaolin and zeolite. Table 12 Exemplary extinguishing agents for high-capacity electric accumulators and other live appliances based on a suspension of the thermally exfoliated vermiculite, a 1 : 1 mixture of metakaolin and zeolite

The obtained sample 1 is the most effective and stable, and it was subjected to further testing as described below in the following Examples, concerning i.a. effectiveness or storage.

In one embodiment of the invention, the extinguishing agent with flame retardant additives for high-capacity electric accumulators and other live appliances comprises the thermally exfoliated vermiculite having a particle size in the range of 1 to 1000 pm, more preferably in the range of 30 to 600 pm, most preferably from 50 to 300 pm.

In another embodiment of the invention, the density of the extinguishing agent for high- capacity electric accumulators and other live appliances is from 1.08 to 1.5 kg/m ³ , more preferably from 1.15 to 1.40 kg/m ³ .

In yet another embodiment of the invention, the solution of alkali silicates comprises a silicic acid sodium salt solution or water. More preferably, the solution of alkali silicates is a silicic acid sodium salt solution

Preferably, the extinguishing agent for high-capacity accumulators and other live appliances according to the invention is based on a suspension of the thermally exfoliated vermiculite obtained by the method according to the invention, or the suspension according to the invention. Example 10. Preparation of the suspension of the thermally exfoliated vermiculite-based extinguishing and/or deactivating agent for photovoltaic panels

On the basis of the thermally exfoliated vermiculite suspended in an aqueous solution of sodium, potassium or sodium and potassium silicates with additives to increase microbiological and physical stability, the extinguishing and/or deactivating agent for photovoltaic panels was developed.

This agent is obtained by adding pigments to the extinguishing agent in amounts of up to 20 % of the dispersion, more preferably up to 17 % of the dispersion, most preferably up to 15 % of the dispersion, which allows to obtain an agent for simultaneous deactivation and extinguishing of photovoltaic panels, for extinguishing photovoltaic panels, or an agent for deactivating photovoltaic panels.

The pigments added to the suspension of thermally exfoliated vermiculite may be liquid and/or powdery pigments. Examples of such pigments include organic or inorganic pigments or a mixture thereof. Preferably, these are pigments that provide a coating that prevents the passage of light. Non-limiting examples of such pigments are: black pigments, black carbon pigment (carbon black), hematite, spinel, rutile pigments (Table 13), or a mixture thereof. The addition of pigments to the suspension of the thermally exfoliated vermiculite creates a lightproof coating on the panel surface, turning it off and deactivating it, and extinguishing the fire if necessary.

Table 13. Examples of the extinguishing and/or deactivating agents for photovoltaic panels based on the suspension of the thermally exfoliated vermiculite

Samples 1,4, 5, 6 are effective and stable. Sample 1 was further tested as described below in the following Examples, concerning i.a. effectiveness or storage.

In one embodiment according to the invention, an extinguishing and/or deactivating agent for photovoltaic panels comprises the thermally exfoliated vermiculite with a particle size in the range of 1 to 1000 gm, more preferably in the range of 30 to 600 pm, most preferably 50 to 300 pm.

In another embodiment of the invention, the density of the fire protection agent for photovoltaic panels is from 1.08 to 1.5 kg/m ³ , more preferably from 1.15 to 1.40 kg/m ³ .

In yet another embodiment of the invention, the solution of alkali silicates comprises a silicic acid sodium salt solution. Preferably, the extinguishing agent for photovoltaic panels and/or the deactivating agent for photovoltaic panels according to the invention is based on the suspension of the thermally exfoliated vermiculite obtained by the method according to the invention, or the suspension according to the invention.

Example 11. Testing the effectiveness of the thermally exfoliated vermiculite suspended in an aqueous sodium silicate solution or water with additives to increase microbiological and physical stability, with flame retardant additives, as an extinguishing agent, and with the addition of a pigment as an extinguishing and/or deactivating agent for photovoltaic panels

To test the effectiveness of the thermally exfoliated vermiculite suspended in an aqueous sodium silicate solution or water with additives to increase microbiological and physical stability, with flame retardant additives as an extinguishing agent, and with the addition of a pigment as an extinguishing and/or deactivating agent for photovoltaic panels, a number of practical tests were carried out, e.g. extinguishing traditional flammable solids, such as lithium- ion battery pack (up to 500 Wh), high-capacity lithium-ion battery (from 500 Wh) (Table 14).

The extinguishing agents were applied to the burning surfaces by spraying/atomizing under pressure using various modifications of fire extinguishers, extinguishing appliances or appliances for distributing, under pressure, deactivating agents for photovoltaic panels. The following parameters were evaluated: the expelling distance of the extinguishing agent from a fire source, the duration of action of the extinguishing agent, the type of extinguishing agent stream, the type of coverage of extinguished objects, the types of extinguished objects. Then, in each of the variants of the experiment, a wait time of minimum of three minutes was added after the end of the extinguishing phase to ensure that no so-called self-ignition, i.e., internal sources of fire that ignite spontaneously, were created.

The stable extinguishing agent based on the thermally exfoliated vermiculite with flame retardant additives was effective in extinguishing both a set of lithium-ion batteries (up to 500 Wh) and a high-capacity lithium-ion battery (from 500 Wh), and photovoltaic panels, creating a dense a layer of a mixture of vermiculite and polymerized silicic acids, or a dense layer of highly concentrated vermiculite and flame retardant additives.

Analogous tests conducted for the stable thermally exfoliated vermiculite-based extinguishing agent with the addition of a pigment have shown that it is effective in extinguishing both a set of lithium-ion batteries (up to 500 Wh) and a high-capacity lithium-ion battery (from 500 Wh) and photovoltaic panels, by creating a dense layer of a mixture of vermiculite and polymerized silicic acids on the extinguished surfaces, and additionally ensures deactivation of photovoltaic panels. Photovoltaic panels, as long as they have influx of light, produce the direct current, after applying the thermally exfoliated vermiculite-based extinguishing and/or deactivating agent with the addition of pigment on the photovoltaic panels, a layer is formed that prevents the access of light - as a result, the voltage drops. Experiments have shown that when the agent is sprayed onto a solar panel, the DC voltage drops to 9 V.

Table 14. Testing of suspension of thermally exfoliated vermiculite-based extinguishing and/or deactivating agents

Example 12. Testing the effectiveness of cleaning photovoltaic panels from the extinguishing agent, the extinguishing agent containing flame retardant additives and the extinguishing and/or deactivating agent for photovoltaic panels

The effectiveness of cleaning photovoltaic panels after the use of the extinguishing and/or deactivating agents was tested (Table 15). It has been shown that it is possible to reuse the photovoltaic panel after washing it and removing the remains of the extinguishing and/or deactivating agent. In one embodiment of the invention, the residual extinguishing and/or deactivating agent remaining on the panel for about 20 hours was removed with a plastic spatula or by hand. However, any items suitable for cleaning photovoltaic panels or similar smooth surfaces can be used (Fig. 11).

In another embodiment of the invention, cleaning was carried out 30 minutes after application using an aqueous solution, preferably water alone. In addition, to obtain a better effect, the cleaned surface or device could be pre-wetted and/or soaked before the actual cleaning by pouring water on the surface and then carrying out the actual cleaning with a soft brush until the surface is clean (Fig. 10).

Then, it was verified whether the cleaned surfaces were reusable. For this purpose, the panel was connected to electricity, and the measured DC parameters were the same as before the agent was applied, i.e. -48 V.

Table 15. Testing the effectiveness of cleaning photovoltaic panels from the remains of the suspension of the thermally exfoliated vermiculite-based extinguishing and/or deactivating agent