The present invention relates to methods of treatment of shells, the use of the shell powder created by such a treatment method and to products incorporating such treated shell powder.

The present invention will be described particularly with reference to the shells of oysters. It can potentially be used for the treatment of the shells of other shellfish.

Oyster shells are produced in large quantities as a by-product of oyster cultivation and harvesting. It is recognised as an urgent requirement to find environmentally safe uses for waste oyster shells. [Feasibility test of waste oyster shell powder for water treatment - “Process Safety and Environmental Protection” Volume 102, July 2016, Pages 129-139], because they otherwise result in a large volume of waste which is generally disposed of in landfill.

The inventor has discovered an answer to this through the treatment of the oyster shell to form a powdered product that can be used inter alia in the creation of:

1. Natural and organic cosmetics. The powdered shells have been found to act as a natural exfoliant that has great benefits for the skin’s epidermal layer.

2. BareNativeNanoNutrient (BN2). Powdered shells have also formed the basis of BN2, a formula designed to create a nano-nutrient product to continue developing an aquatic remediation program (ARP) that has the potential to enhance and maintain good water quality for aquatic management systems around the world. A program, the successful introduction of which would have a significant impact on climate change. Previous treatments for oyster shells have used harsh abrasives and cleaning chemicals which are neither environmentally desirable nor sustainable.

Oyster shell powder contains important trace elements: Iron, Copper, Zinc, Magnesium, Phosphorous, Potassium, Manganese and Calcium carbonate. The Colchester Native Oyster (0 strea Edulis) is different in appearance to all other breeds of oysters and presents its own unique set of problems. 83% of the Colchester Native Oyster is shell and cannot be dumped straight back into water for a period of 12 months as they can harbour the Bolavia virus, which can kill off nearby living oysters and other molluscs. Consequently, waste oyster shells are sent to landfill presenting a public health and waste problem.

This long wait time proves economically inefficient for oyster farmers, so it is aim of the present invention to provide a clean and safe solution by creating a quicker and more efficient solution to making oyster shells safe again by the reuse and recycling of oyster shell residues.

All existing method involved harsh chemicals, bleaches and abrasives to strip the oyster shell of any impurities. In contrast the present invention provides a method that ensures that no harsh chemicals or abrasives are used. After extensive trials, investigations and testing, a cleaning process that is all-natural as well as quick and safe has been found. This is a natural way of cleaning oyster shells and grinding them into a powder that poses no threat to any part of the environment - and instead benefits it.

According to a first embodiment of the present invention there is provided a method for treating oyster shells to form oyster shell powder, the method comprising: a. crushing oyster shells in a crusher to form large diameter crushed shells; b. boiling the large diameter crushed shells for 30 minutes in water; c. draining the crushed shells; d. baking the drained crushed shells for 30 minutes in an oven; e. whilst still warm, milling the crushed shells to a fine powder; f. sieving the powder through a 60 micron mesh sieve and removing any larger particles; g. allowing the sieved powder to cool; h. baking the cooled powder in an oven for 30 minutes; i. allowing the powder to cool; j. again sieving through a 60 micron mesh sieve and removing any larger particles; and k. baking the oyster shell powder in an oven for 30 minutes.

The cooling at steps g and i can be done passively (with the cooling happening due to the lower ambient temperature) or it can be done actively with some form of assisted cooling system. Ideally the colling is passive. Ideally cooling at the cooling step g and/or i is for at least 24 hours.

The baking steps are all ideally carried out at a temperature of at least 190- 210°C. Each baking step d, h and k may be done at the same temperature or may be done at varying temperatures. Preferably the temperature of each baking step is approximately 200°C. The baking steps have a minimum duration of 30 minutes as noted above.

However, the duration is an approximate minimum time and the baking steps could be carried out for longer. It has been found that 30 minutes provides sufficient benefit. Baking for much longer provides insufficient benefit when compared to the cost.

The crushing at step a and the milling at step e are carried out using any of the techniques known in the art for mechanical crushing and milling. Ideally milling at step e is done in a hammer mill. This can also be used for step a, but a rolling mill may be useful as well.

Various types of oven may be used as long as they able to hold the temperature at the required level for the required minimum duration. Ideally the oven used at one or more of the baking steps is a fan oven. The baking can be a batch process where a batch of crushed or powdered shells is inserted into an oven on a suitable tray, is heated and then is removed for subsequent processing. Alternatively, a continuous process can be used with a suitable transit time through a tunnel oven.

A powder that will pass through a 60 micron mesh sieve is ideal for the uses envisaged for the powder produced by the present invention. However, a finer powder with a smaller size can be achieved as required. Such milling would use appropriate milling equipment and the sieve used would have a suitable mesh size to suit the desired end product characteristics.

The shells crushed are preferably those of the native oyster.

According to a further aspect of the present invention there is provided crushed oyster shell powder produced by a method as described above. Such powder may have a maximum particle size of 60 microns or smaller depending on usage.

A main development objective of the present invention is to provide components for use in cosmetic and/or washing formulations. Therefore, according to yet further aspect of the present invention there is provided a cosmetic or washing composition comprising crushed oyster shell powder produced by a method as described above.

Ideally that cosmetic or washing composition is used for skin care. The crushed oyster shell powder may serve as an exfoliant or abrasive component in the formulation. According to a still further aspect the present invention provides the use of oyster shell powder produced by a method as described herein in the manufacture of cosmetics or toiletry formulations.

In order that it be better understood, but by way of example only the present invention will now be described with reference to the accompanying drawing in which:

Figure 1 is a schematic representation of an embodiment of a method according to the present invention.

As shown in Figure 1 , whole oyster shells 2, which after removal of the oyster flesh are a by-product of the cultivation and harvesting of oysters, are crushed in a mill 4 (a rolling mill in this representation but any form of mill will work). The product of this first milling is course textured granular matter 6. This coarse granular matter 6 is added to water and boiled in a kettle 8 for 30 minutes.

The granular matter is drained and then introduced to an oven 10 where it is heated to 200°C for at least 30 minutes. Whilst still warm from the oven the granular matter is passed through a second mill 12. The powder 14 produced is passed through a mesh 16 to remove particles larger that 60 microns. This large particulate matter can be discarded or returned to the second mill 12. The sieved powder 17 is then allowed to cool for 24 hours before being introduced to an oven 10 and heated to 200°C for at least 30 minutes. The powder is again allowed to cool for 24 hours before being sieved again through a second mesh 18. Larger particles above the target mesh size (60 microns in this embodiment) are removed (and may be discarded or returned to the second mill 12). The sieved powder is then again introduced to an oven 10 and heated to 200°C for 30 minutes. After this the powder is allowed to cool to ambient temperature at which point it is ready for use. The powder formed by this method can be used in various ways. It is particularly suitable for preparing cosmetic and toiletry formulations such as body and facial scrubs. Such a formulation may comprise a suitable cleansing base (containing usual ingredients such as surfactants, emollients and humectants) to which is added a suitable proportion of powdered oyster shells to act as an exfoliant.

The process that has been invented provides a natural and organic way to clean waste oyster shells to ensure that they can be safely used to provide financial, environmental and health benefits when safely used in cosmetic products. In addition, the disposal of the product can be a further benefit to waste water systems. The invention provides a use for oyster shell waste thus keeping it from landfill.

In addition to use in cosmetics the powder produced by the method of the present invention can potentially be employed in other situations. For example, it has the potential to be used in waste water treatment for stabilisation/solidification of heavy metals, as well as the removal of phosphate, and sulphur, encouraging a healthier aquatic ecosystem.

In further embodiments, the applicant has found that some steps of the process provided in the example may be reduced but nonetheless permit a natural cleaning and milling process to be used to produce a useful osytershell product. In a further embodiment of the invention the following process may comprise the following:

- Crushing of oyster shells to a large grit;

- Boiling crushed shells for 30 minutes in water and straining therafter;

- Hammering the crushed shells, whilst warm, in a mill to a fine (pure white) dust;

- Sieving the dust, optionally with a 60 micron mesh sieve, to remove grit/particles;

- cooling the resulting powder, optionally for 24 hours;

- Baking the powder, optionally in a fan oven at 250 degrees centigrade; and

- Cooling the powder, optionally for 24 hours.

Where the same step is indicated as provided in the earlier described process, the optional parameters and conditions associated with that particular step may also be optionally applied to this embodiment.

In such cases, the oyster shell product from the process is suitable to be used/applied in several applications, as it meets cosmetic and food grade standards

Such examples include but are not limited to abrasive or exfoliant composition production - which may by useful as cosmetic products.