RU2214461C2 - Method and plant for reworking aluminum tins - Google Patents

Abstract

FIELD: production of aluminum lamella of different degree of dispersity. SUBSTANCE: proposed method includes grinding, removal of iron inclusions and cleaning of organic admixtures. Grinding is performed at four stages: at first stage, particles of 15-25 mm in size are obtained; at second stage, particles of 3-8 mm in size are obtained and at third stage, particles not more than 1.5 mm in size are obtained; at these stages, grinding is performed in drum-type rotary grinders and fourth stage is performed in abrasion-type apparatus for at least 2 hours. Plant proposed for realization of this method, includes grinding unit and magnetic separator and is additionally provided with gas blower, classification unit and three rotary drum-type grinders mounted in series and abrasion apparatus. As a result, lamella of required sizes are obtained which are perfectly cleaned from organic inclusions. EFFECT: enhanced efficiency. 6 cl, 1 dwg, 1 tbl, 1 ex

Description

 The invention relates to the field of producing aluminum flakes and powders of varying fineness from aluminum beverage cans.

A known method of processing aluminum cans for drinks, which consists in the fact that the cans are fired at 400-600 ^o With to remove organics and crushed in a reflective grinder (Japanese application 5067687, 2807740).

 A disadvantage of the known methods is the need to heat the source material during its processing to remove organic impurities, which increases the cost of the process, worsens the ecology of production.

 There is a method of processing aluminum cans from drinks, which consists in the fact that the cans are crushed and separated iron inclusions (JP 01-287231, C 22 V 21/06, publ. 11/17/1989, abstract). This method is taken as the closest analogue.

 This method does not remove organic impurities from the resulting product and requires further processing by remelting.

 A known installation for the processing of scrap aluminum cans from drinks, consisting of a grinding device and a magnetic separator (JP 01-287231, C 22 V 21/06, publ. 11/17/1989, abstract). This setting is taken as the closest analogue.

 The disadvantage of this device is the inability to obtain small flakes, purified from surface contaminants (paints, organics, etc.).

 An object of the invention is to obtain from scrap aluminum cans of flake scales and powder of a given size, maximally purified from organic contaminants.

 The problem is solved in that in a method for processing aluminum cans from drinks, including grinding and removing iron inclusions, organic impurities are cleaned, and grinding is carried out in four stages, to obtain particles of 15-25 mm in size in the first stage, in the second stage with obtaining particles of 3-8 mm and in the third stage to a particle size of not more than 1.5 mm, while in the first three stages, grinding is carried out in rotary drum grinders, and the fourth stage in the abrasion apparatus is not m her 2 hours.

 The crushed particles after or during the grinding process are subjected to sieve classification with the removal of fractions less than 0.2 mm

 Purification from organic impurities is additionally carried out by grinding it by removing fractions of less than 0.2 mm by a continuous stream of gas passing through rotary drum grinders and an abrasive apparatus.

 Installation for processing aluminum cans, containing a grinding device and a magnetic separator, is additionally equipped with a gas blower, devices for classification and contains three sequentially installed rotary drum grinders and abrasion apparatus.

 As an abrasion apparatus, the apparatus comprises a ball or rod mill.

 Classification devices are placed after each or in each rotary drum grinder and abrasion apparatus.

The drawing shows a diagram of an installation for processing aluminum cans
The installation consists of rotor-type grinders 1, 2, 3 with interchangeable grids installed in series, and an abrasive apparatus 4 - a ball mill. The grinder 1 is equipped with a magnetic separator 5. The grinder 2 has a classifier b and a capacity 7 at the output. The grinder 3 has a classifier 8 and a capacity of 9 and 10 at the output. The ball mill 4 has a classifier 13 and a capacity of 14. The plant has a gas blower 11 and a cyclone 12.

 The source material is loaded into a grinder 1, crushed to a particle size of not more than 25 mm and fed to a magnetic separator 5, where iron inclusions are removed from the material. Then the material enters the grinder 2, where it is crushed to a particle size of not more than 8 mm From the grinder 2, the material is fed into the classifier 6, from where a fraction of less than 8 mm enters the grinder 3, and a fraction of less than 0.2 mm enters the tank 7 and is removed from the process.

 The material received in the grinder 3, is crushed to particles no more than 1.5 mm and fed into the classifier 8, in which the material is divided into several fractions. A fraction of less than 0.2 mm is fed into the tank 9 and removed from the process, the rest of the product is fed to the mill 4. If necessary, have as a finished product a material with a fraction of less than 1.5 mm, but more than 0.2 mm, it is fed into the tank 10 .

 In a ball mill 4, the material is abraded by the balls, and it acquires the necessary dimensions depending on the time of its processing. Processing lasts from 2 to 10 hours.

 In the process of grinding the material in the mill 4, gas is passed through it from the gas blower 11, which removes particles of less than 0.2 mm from the mill. These particles contain organic impurities and they are removed from the process, thereby cleaning the remaining material from organic impurities. The dust-gas mixture from the mill 4 enters the cyclone 12, where it is cleaned of solid particles, and the gas is released into the atmosphere.

 For a more complete removal of organic impurities, a gas purge is carried out from the gas blower 11 of all grinders in the process of grinding material in them.

 As a gas, you can use air while maintaining the dust concentration in it below the permissible concentration limit of flame propagation, or a protective gas, for example nitrogen with an oxygen content of not more than 12%.

 From mill 4, the material enters the classifier 13, from which the material classified by fractions enters the tank 14 as a finished product or source material to obtain high-quality pigment or pyrotechnic powder or powder.

An example of the method
Used aluminum cans were crushed in rotary grinders, isolating the corresponding particles of the fraction by size:
at the 1st stage 7-20 mm
at the 2nd stage 7-2 mm
at the 3rd stage 2-0.5 mm
The thinnest part of the product (mainly smaller than 0.2 mm) was separated by sieve classification and air blowing.

After the 3rd stage, the crushed product contained 6-12% fractions smaller than 0.2 mm. This part of the product is a dusty fraction containing less than 90% aluminum, and the rest is dirt (mechanical impurities) and organic matter exfoliated from the surface of the particles (cellulose fibers, dry paint, varnish, etc.)
The particles obtained after each grinding stage had a partially cleaned surface of a shiny or dull color, which allows them to be used for decorative purposes. Coarse fractions after grinding contained more than 96% aluminum and can be used in the chemical and metallurgical industries.

 The method is investigated in a pilot industrial and laboratory installations. The stage of abrasion was investigated on a laboratory ball mill with a diameter of 140 mm with a ball load of 4, 7 kg.

 The resulting powder was ground in a laboratory mill. After abrasion in the mill, removal of the -0.2 mm fraction from the product and sieve classification, the products were compared with standard powders of PA grade and PAP and PP powders. The results are shown in the table.

 As can be seen from the table, the obtained powder is similar in size and particle shape to the powder of grades PAP-1 and PAP-2 and differs only in a high content of impurities.

Claims (6)

 1. A method of processing aluminum cans from drinks, including grinding and removing iron inclusions, characterized in that they are purified from organic impurities, and grinding is carried out in four stages, with particles of 15-25 mm in size being obtained in the first stage, and in the second stage to obtain particles of 3-8 mm and in the third stage to a particle size of not more than 1.5 mm, while in the first three stages, grinding is carried out in rotary drum grinders, and the fourth stage in the abrasion apparatus for at least 2 hours  2. The method according to claim 1, characterized in that the crushed particles after or during the grinding process are subjected to sieve classification with the removal of fractions less than 0.2 mm  3. The method according to claim 1 or 2, characterized in that the purification from organic impurities is additionally carried out by grinding by removing fractions of less than 0.2 mm by a continuous stream of gas passing through rotary drum grinders and an abrasive apparatus.  4. Installation for processing aluminum cans from drinks, containing a grinding device and a magnetic separator, characterized in that it is additionally equipped with a gas blower, devices for classification and contains three sequentially installed rotary drum grinders and abrasion apparatus.  5. Installation according to claim 4, characterized in that as the abrasive apparatus contains a ball or rod mill.  6. Installation according to claim 4 or 5, characterized in that the classification device is placed after each or in each rotary drum grinder and abrasion apparatus.

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