Technical Field

The invention relates to a screen mechanism, developed for use in lacquer removal furnaces used in scrap aluminum recycling, which removes organic components consisting of paints and oils and inorganic components consisting of various lacquers from the surface without uncontrolled combustions occurring due to exothermic reactions before the melting process for recycling aluminum.

State of the Art

Recycling is a very important issue for the protection of the world. Some metals or substances take a long time to decompose and dissolve in nature, or the dissolution of such materials in the natural environment may leave harmful substances to the environment. One of the materials that takes a long time to decompose or dissolve in the natural environment is aluminum. There is no limit to how many times aluminum can be recycled, and it can be recycled many times. Therefore, aluminum is actually an excellent material for recycling. It is possible to recycle aluminum by melting it, and then to cast the liquid aluminum and reshape it. The fact that aluminum can be melted repeatedly without changing its properties is an important reason for aluminum recycling efficiency.

In order to recycle aluminum wastes, the collected aluminum wastes are first taken to a recycling facility. Aluminum scrap waste is then put on the belt conveyors of the factory. At this stage, the metal parts in the aluminum wastes can be separated with the help of a large magnet. This way, aluminum is cleaned from all metal parts and then passed to the washing stage. The washed parts are separated into small pieces by pressing machines and taken to the melting furnaces. The aluminum, which is completely melted in the melting furnaces, is cast into molds in liquid form and turned into ingots. This way, it is much easier to obtain raw aluminum. These ingots (raw aluminum) are sent to factories that need aluminum material to make new products.

To recycle aluminum, it is necessary to remove the organic and inorganic components from the surface before melting. While organic components are paints, oils, inorganic components are various lacquers used. Uncontrolled combustion occurs due to exothermic reactions that occur when scrap aluminum is charged directly to melting furnaces. This leads to excessive slag formation during melting and increases metal losses.

In rotary type lacquer removal furnaces, there are two types of applications depending on the process air flow direction in the drum and the scrap aluminum flow direction. The system in which the air flow direction is the same as the scrap aluminum flow direction is defined as "cocurrent". The system where the air flow direction is opposite to scrap aluminum is defined as "countercurrent". However, energy efficiency is low in these systems due to the lack of reuse of waste hot air. Depending on the type of scrap aluminum, organic components move away from the surface when it rises to preheating temperature. However, inorganic components such as lacquer remain on the surface. They are separated from the surface as a result of friction of scrap parts crushed by rotary type furnaces with each other. However, in the currently used lacquer removal furnaces, the dust particles resulting from the separation of the lacquer from the surface remain on the surface. For this reason, after the lacquer removal furnace, they are removed by means of a screen on the conveyor. However, since they are not removed during the process, the dust particles remaining on the surface increase the formation of slag during melting. This situation increases metal losses.

One of the studies to carry out the temperature control of a rotary heating furnace by heating and circulating the exhaust gas in the rotary heating furnace and refeeding it into the furnace is the invention that is the subject of patent application JP2012125666A. Metal scrap processing device, which is the subject of the invention comprises a raw material feeding device, which includes a shredder and a supply feeder for metal scrap (raw materials); an induction heating and circulation air supply pipe for the supply of high-temperature air to the cylindrical rotating body, which includes a heating device that heats the cylindrical rotating body with electromagnetic energy, performing heat treatment by feeding the raw material from the feeding path at one end and rotating it in a cylindrical rotating body, and discharging it at the other end; a discharge pipe, provided at the other end, which recovers the processed raw material and discharges the combustion gas; dust collector, which removes non-solid solids from combustion gas and feeds it as exhaust gas into a secondary combustion furnace; a secondary combustion furnace, which thermally decomposes the exhaust gas at high temperature and discharges it as high-temperature air; a cooling tower, which adjusts high-temperature air to a predetermined temperature; and a circulation fan that circulates high-temperature air into the circulating air supply pipe of the rotary heating furnace and refeeds it.

Another study is the invention that is the subject of patent application EP0523858 (A1 ). This invention relates to an apparatus developed for heat treatment of scrap materials, in particular for the decontamination of aluminum can scrap. The said apparatus has a rotary furnace, which describes a furnace room in which the material is fed. The inlet end, the rest of the gas circulation vehicle, typically includes a final burner through which exhaust gases are recirculated, located at the inlet end of the furnace to provide a compact, unified and easily adaptable structure with heat losses.

Therefore, the presence of the need for a lacquer removal furnace screen mechanism, which eliminates the disadvantages of the present technique, and the inadequacy of the existing solutions necessitated an improvement in the relevant technical field.

Brief Description of the Invention

The present invention relates to a screen mechanism that meets all the requirements mentioned above and provides some additional advantages, developed for use in lacquer removal furnaces used in scrap aluminum recycling, which removes organic components consisting of paints and oils and inorganic components consisting of various lacquers from the surface without uncontrolled combustions occurring due to exothermic reactions before the melting process for recycling aluminum.

Based on the known state of the art, the objective of the invention is to heat the scrap material in the channel by passing the air through the hot air duct in the developed screen mechanism.

The objective of the invention is to ensure that the waste gas is used in the screen mechanism by passing the partially cooled air at the outlet over the material again and reusing it in the pre-heat treatment of the material, thus increasing the efficiency.

Another objective of the invention is to ensure that the inorganic components are separated from the surface and remain under the screen by means of the abrasion vanes positioned in the lacquer removal furnace. Another objective of the invention is to ensure that the inorganic components remaining under the screen are removed from the process by means of thescrew conveyor system.

Another objective of the invention is to remove both organic and inorganic components from the surface during thermal pre-treatment, allowing clean scrap to be charged directly to the melting furnace without the need for extra processing.

The structural and characteristic features and all the advantages of the invention will be understood more clearly by means of the figures given below and the detailed explanation written with the references to these figures, therefore the evaluation should be made by considering these figures and detailed explanations.

Brief Description of the Figures

In order to understand the structure of the existing invention and its advantages with additional elements in the best way, it should be evaluated together with the figures described below.

Figure-1 ; is the schematic dismantled view of the of the screen mechanism,

Figure-2; is the schematic view of the cross-section of the screen mechanism,

Figure-3; is the schematic view of the scrap material loading channel of the screen mechanism and its installation on hot air duct.

Reference Numbers

100. Screen mechanism

101 . Material guiding vanes

102. Drum

103. Screw conveyor system

104. Abrasion vanes

105. TC unit

106. First ring

107. Drive gear

108. Separator support pipes

109. Second ring

110. Separator channel 200. Hot air duct

201 . Air duct support foot

300. Scrap material loading channel

400. Air suction

Detailed Description of the Invention

In this detailed description, a screen mechanism (100), which is the subject of the invention, developed for use in lacquer removal furnaces used in scrap aluminum recycling, which removes organic components consisting of paints and oils and inorganic components consisting of various lacquers from the surface without uncontrolled combustions occurring due to exothermic reactions before the melting process for recycling aluminum is described only for a better understanding of the subject and without creating any limiting effect.

The screen mechanism (100) shown in Figure-1 comprises a drum (102) that prevents dust particles separated from scrap surfaces from sticking to the surface and make them remain under the screen. The said screen mechanism (100) basically comprises material guiding vanes (101 ), drum (102), a screw conveyor system (103) and abrasion vanes (104). In order for the scrap material to move forward in the drum (102), there are material guiding vanes (101 ) on the inside of the drum (102). On the outside of the said drum (102), the screw conveyor system (103) is positioned for the transport and transfer of dust particles separated from the surface.

The abrasion vanes (104) shown in Figure-2, which are positioned on the entire inner surface of the drum (102), ensure the mechanical abrasion of the inorganic components on the material surface. In the said screen mechanism (100), preferably 2 TC units (105) are disposed on the outside of the drum (102) for temperature control. In the screen mechanism (100), the radial load is carried by the first ring (106), and both the radial and axial loads are carried by the second ring (109). The said first ring (106) is located in the outer circumference of the drum (102) near the hot air inlet and the second ring (109) is located in the outer circumference of the other end. The drive gear (107) is positioned on its outer surface to rotate the drum (102). There is an air duct support foot (201 ) in the drum (102) for the transport of the hot air duct (200). Separator support pipes (108), which are used to remove inorganic compounds from the surface after mechanical abrasion, form a screen channel and work together with screw conveyor system(103). The separator channel (110), where inorganic substances separated from the surface of the scrap material are collected under a screen, is located at the bottom of the drum (102).

In the screen mechanism shown in Figure-3 (100), the hot air needed for thermolysis enters the hot air duct (200) passing through the central part of the drum (102). The scrap aluminum is fed into the lacquer removal furnace drum (102) from the scrap material loading channel (300) located at the top. In the said screen mechanism (100) hot air suction is realized from air suction port (400). The air from suction port (400) is transferred to the cyclone, circulation fan and afterburner respectively and fed back into the lacquer removal drum (102)

In the screen mechanism (100) of the invention, there are air duct support feet (201 ) in the furnace drum (102) and hot air duct (200) fixed to the drum (102). The air passing through this hot air duct (200) heats the material. The partially de-heated air from the hot air duct (200) is directed into the drum (102) through air suction (400) and comes into contact with the surface of the scrap material. In this way, organic components are separated from the scrap aluminum surface by preheating. The process of separation from the scrap surface is the removal of organic components from the surface as a result of the combustion reaction. However, the inorganic components (lacquer and the like) on the surface do not separate from the surface as a result of the preheating process. Therefore, a mechanical separation process is needed. Therefore, aluminum scrap is fed through the scrap material loading channel (300), and after they fall on top of the material guiding vanes (101 ), the furnace drum (102) begins to rotate to make its forward movement. There is a drum (102) that allow the furnace drum (102) to rotate and there are two rings (106, 109) for supporting the drive gear (107). The first ring (106) carries the radial load, while the second ring (109) carries both the radial and axial loads. The forward movement is achieved by the rotational movement of the drum (102) and the angle in the position of the drum (102). Due to the angle in the drum (102), the material gradually moves forward. During this progress, the inorganic component on the outer surface of the scrap that is impacted by abrasion vanes (104) decomposes from the surface. Unwanted components separated from the surface are transported to the separator channel (110) through the drum (102). Separator support pipes (108) provide the separator channel (110). By means of the screw conveyor system(103) in the separator channel (110), unwanted components are removed from the process.