The present invention relates to a method for recycling post-consumer oil and fuel filters, allowing for a recovery of all components separately.

Vehicles are equipped with various types of oil, air and fuel filters, which remove contaminants and, at the same time, are gradually consumed and become waste. From a technical point of view, they consist of the housing and the working components hidden inside. They are composed of various types of metals, plastics and cellulose, all of which is saturated with liquid hydrocarbons, such as oils and fuels, in which variable amounts of impurities, such as dust and metallic, mineral, biological and other particles are suspended. They are most often utilised by incineration. This is the simplest, but also the least effective method, as only a small amount of thermal energy and metal scrap are recovered at the expense of consumption of the electrical energy needed to prepare the feedstock and purify the exhaust fumes.

Since modern filters are constructed of either steel or aluminium, the feedstock mixture subjected to incineration has a very high temperature, which implies that only a part of the heavily contaminated iron is recovered. In addition, various kinds of sorbents, including absorption coals and coke, which subsequently become waste, are used.

For many years, a method that would allow for the recovery of the individual components of the filters, such as iron, aluminium and other components to re-use or apply them as energy carriers, has been searched for. Attempts to apply manual disassembly have been made, but due to the slowness of this operation, its cost and amounts of waste filters, it is uneconomical. The same applies to mechanical disassembly, as the variety of filter types makes this very difficult.

The most commonly a mixture of fragmented filters after the removal of fluid was treated as a steel scrap intended for melting. At present, the amount of steel in mixed filters equals approx. 30%. This does not exceed 60% in selected steel filters, and the remaining are non-ferrous components.

As mentioned above, during the incineration of filters, the contaminated iron for smelting is recovered, while the aluminium contained in the filters is irretrievably lost. Since aluminium is obtained by electrolysis of aluminium oxide or chloride at the expense of huge amounts of electrical energy obtained in power plants, with the formation of carbon dioxide or nuclear waste, the loss of this raw material contained in post-consumer filters is an important disadvantage of the existing methods. Destruction of aluminium, used in increasing amounts in various branches of industry, owing to the fact that it is a light, non-toxic, easily biodegradable metal, but unfortunately rather expensive, should not happen. Therefore, better methods for its recovery are sought after.

The Korean description of the invention KR 101086350 discloses a method for cleaning filters from fuel impurities and their re-use. In the era of modern and expensive cars, this method is not accepted in many countries or can even lead to a failure of a vehicle or the loss of warranty.

Some methods involving cutting off a filter cover, washing its interior to rinse the fuel and subsequent compression of the residue are known. These methods are not intended to obtain the individual components, such as paper, iron or aluminium, separately.

There are also methods for precise cutting of filter lids to recover at least one of their fragments. The residue is washed in order to remove fuels, lubricants or other impurities, and the residue is subsequently compressed and/or incinerated or melted.

During the works aimed at both ecological and economically favourable separation of the components of post-consumer filters, it was found that it is possible to separate iron, aluminium and paper components, as well as hydrocarbons, which used to be components of lubricating oils, from a mixture of post-consumer filters.

The method of the invention is characterised in that mixed, pre-cut filters, irrespective of their nature and origin, are subjected to a hydrocarbon solvent from a group of petroleum derivatives, which dissolves oils, with simultaneous stirring. The process is carried out in the main tank, filled with the solvent. The fragmented filters immersed in the solvent undergo separation into metals, paper and fuels or lubricants dissolved in the solvent. The paper suspended in the solvent moves to the top of the tank, where it is collected, while the metals, including ferrous and non-ferrous metals, fall to the bottom. Under the bottom of the main tank, inside the separator, there is a rotating disc, whose plane is arranged at 15-45° in relation to the vertical. On the periphery of the disc, inside its material, there are magnets. Below the elevated edge of the disc, there is a container for ferrous metals, which are attracted by the edge of the disc. Near the elevated edge of the disc, there is a tool for collecting the attracted ferrous metals from the disc. Under the lowered edge of the disc, there is a container for aluminium, which falls downwards along the disc. The separated components are separated from the solvent using known methods. The solvent is evaporated from the solution containing oils and lubricants, and the residue is intended for use, for example, for combustion.

The method, according to the invention, is simple; it does not require precise cutting tools, as the filters are fragmented in any way, without segregation depending on the filter type; there is no need to adjust the size of the cutting tools to the size of the filter; and above all, this allows for a separation of all components of the filter.

The subject of the invention was illustrated in a drawing, wherein Fig. 1 presents a scheme of a system for filter recycling, and Fig. 2 presents a cross- section of the disc with magnets.

Example 1. The apparatus consisted of a main tank 1 , i.e. a two-piece cylindrical apparatus, closed with a conical bottom with a centrally situated tube, which performed an initial separation of the contents of the main tank 1, directing heavy pieces of metals down to a sorter 3. Inside the main tank 1, a stirrer 2 was placed. The stirrer 2 rotated at a rate of 30 revolutions/minute. The main tank 1 was sealed at the top with a lid with a tube welded centrally inside. At half the height of this tube, a stub pipe was placed, used to discharge the suspension of papers with the solution to a centrifuge 11 , where the suspension was separated, and the solution was directed to an evaporator 8; the precipitate was subsequently rinsed with pure solvent, and all solutions were directed to the sorter 3, and finally the residue of papers wetted with pure solvent was removed and directed to a dryer 10, where the solvent was removed by heating with fumes generated by the evaporator 8 and purged with steam. The hot, wet precipitate of papers was removed. Heavy pieces of metals, i.e. ferrous and non-ferrous scrap, which fell into the sorter 3, were separated inside using a rotating disc 4, equipped with magnets 12 on its periphery to distinguish aluminium scrap from iron scrap. The plane of the rotating disc 4 was placed at 45° in relation to the vertical. Below the elevated edge of the disc 4, there was a container for ferrous metals 6, such as steel and iron, which are attracted by the magnets 12 on the edge of the disc 4. On the edge of the main tank 1, near the elevated edge of the disc 4, there was a tool for collecting the attracted ferrous metals from the disc 4. Under the lowered edge of the disc 4, there was an aluminium container 7. Aluminium, which falls downwards along the disc 4, was directed to the aluminium container 7. The iron scrap, collected by a collecting device 5, fell into the container for ferrous metals 6. The condensate obtained in the containers 6 and 7, as well as generated and obtained in the dryer 10, were directed into a separator 9, where also the solvent collected to rinse the precipitate in the centrifuge 11 and the solvent fed to the containers 6 and 7 were stored. A raw material, i.e. filters cut into pieces of dimensions not greater than 35 mm in an amount of 5000 kg comprising: 33.4% by weight of iron, 25.4% by weight of aluminium, 23.6% by weight of oils, 15.8% by weight of papers, 0.8% by weight of fine minerals and 1 % by weight of water, was prepared. In the separator 9, there was 10 tonnes of technical xylene, used as a solvent. The apparatuses 1 , 3, 6 and 7 were filled with xylene, and 600 kg of xylene were poured into the evaporator 8; the stirring and heating of said evaporator, and subsequently of an apparatus for steam generation, were then started. When the temperature in the evaporator 8 exceeded 110°C, the entire apparatus was started, and subsequently the feeding of xylene at a rate of 60 kg/hr. to the containers 6 and 7 through their outlet valves was started. In turn, the feeding of xylene, necessary to wash the precipitates, at a rate of 305 kg/hr. into the centrifuge 11 was started. The heating of the dryer 10 and the feeding of steam superheated to 110°C were started, and the outlet of its screw closure was sealed with a piece of an easily recognisable fabric, which was followed by dosing the raw material through the fill pipe of the main container 1 at a rate of 250 kg/hr. After twenty hours, despite the consumption of all the raw material, the operation of the apparatus was not stopped, and the outlet of the screw closure was observed. Two hours later, nothing more was pushed out through that outlet the feeding of xylene to the entire apparatus was switched off, and xylene was removed using the outlet valves of the containers 6 and 7, while it was simultaneously fed to the evaporator 8 at a rate of 500 kg/hr. Once the feeding of xylene was completed, the outlet valves of the containers 6 and 7 were closed, and their heating was started, and the distillate was subsequently collected through a valve located at the lowest point of the sorter 3. The distillate was fed into the separator 9. When all xylene was collected, water was injected into the outlet valves of the containers 6 and 7 at an amount of 6 kg per each container, which turned into steam and pushed the rest of xylene vapours from the containers 6 and 7 to the sorter 3. The condensate, as previously with the solvent, were collected from the sorter 3 and transferred to the separator 9. Once the collection of the condensate was completed, the entire apparatus, except for the stirrer and the heating of the evaporator 8, was switched off. When the temperature in the apparatus exceeded 190°C, the heating was switched off, and within one hour, 10 kg of water was evenly fed, while the residues of xylene were removed, and the stirring of the apparatus was subsequently switched off. The following day, when the entire apparatus was cooled down, the evaporator 8 and the containers 6 and 7 were emptied, and the process was then balanced to obtain:

Used raw material 5000 kg

recovered

Iron scrap 1670 kg

aluminium scrap 1270 kg

contaminated oil 1180 kg

paper after drying 830 kg

solvent loss equalled 1 kg

Water was not balanced

Example 2

The apparatus and the method were as described in Example 1. 1 ,2- dichloroethane, characterised by a boiling point of 83.5°C and a density of 1.2529 g/cm ³ at 20°C, was used as a solvent. Filters cut into pieces of dimensions not greater than 35 mm in an amount of 5000 kg comprising: 60.0% by weight of iron, 10.8% by weight of aluminium, 15.2% by weight of oils, 12.8% by weight of papers, 0.2% by weight of fine minerals and 1% by weight of water were used as a raw material.

After completion of the test, the following result was obtained:

Used raw material 5000 kg

recovered

Iron scrap 3000 kg

aluminium scrap 540 kg

contaminated oil 770 kg

paper after drying 640 kg

Solvent loss equalled 1.4 kg

Water was not balanced