Separation and purification method of electrolytic aluminum scraps

Abstract

The invention discloses a separation and purification method of electrolytic aluminum scraps, characterized by comprising the following steps of: crushing electrolytic aluminum scraps in a wet type, floating and magnetically separating, firstly removing iron and silicon and separating to obtain carbon powder and another raw material A; and putting the raw material A in an electric furnace, electrifying to dissolve fluoride salt, restoring harmful impurities in the scraps into an elementary substance metal state by utilizing metal aluminum, precipitating at the bottom of the electric furnace and secondarily removing the iron and the silicon to obtain an electrolyte B. The invention has the advantages that metal aluminum particles in electrolytic aluminum scraps in the electric furnace is utilized as a low-cost reducing agent to restore and precipitate iron, silicon and other harmful impurities at the bottom of the furnace when the fluoride salt is in a dissolved state so as to solve the problem that iron fluoride with high stability is hard to remove, and the reducing agent is utilized in the floatation process to improve the magnetic separation effect. For a product obtained in an electric furnace melting system, an acid-method process is adopted to convert alumina into cryolite, thirdly remove silicon and obtain a byproduct of ammonium bicarbonate.

Description

technical field [0001] The invention relates to a method for separating and purifying electrolytic aluminum waste, which belongs to the technical field of electrolytic aluminum waste recovery. Background technique [0002] Electrolytic aluminum waste includes: alumina dirt and pallet materials mainly composed of fluorine-containing alumina; fire eye carbon slag mainly composed of fluoride salts; anode ash and cathode blocks mainly composed of carbon-containing materials, due to electrolytic aluminum waste The complex components make it very difficult to separate, purify, and synthesize waste materials; for a long time, traditional aluminum industry giants such as the United States, Japan, and Germany, as well as large domestic state-owned aluminum factories such as Guizhou, Xining, Fushun, etc., have all dealt with electrolytic aluminum waste A lot of research has been carried out, but due to the inability to break through the relevant technical bottlenecks, an effective res...

AI Technical Summary

Problems solved by technology

Therefore, the iron, silicon and other impurity elements in the waste cannot be eliminated, which is a key issue restricting the recycling of electrolytic aluminum solid waste resources

[0005] Furthermore, my country has not formulated recycling standards for electrolytic aluminum waste, which brings unpredictable impurities into the waste recycling, which increases the difficulty of processing.

[0006] In addition, due to the different geographical environment of each aluminum plant, the impurity components in the waste are also different, it is very difficult to design a wide adaptability impurity removal process system, which is also one of the key factors that plague the treatment of electrolytic aluminum solid waste

[0007] In the prior art, the recovery method of electrolytic aluminum waste is as follows: (1) through simple flotation, only a small part of fluorine-containing waste in the waste can only be roughly separated from carbon and reclaimed in the fire eye carbon slag, and various The main components (alumina, cryolite, carbon powder, and other harmful impurities (impurities are uncertain)) cannot be completely separated, the purity is low, and iron and silicon are seriously exceeded, which cannot reach the industrial application level

[0008] (2) Remove iron (Fe) by chemical methods. A considerable part of the iron in the waste exists in the form of iron fluoride salts, and the high stability of fluoride salts is the key technical bottleneck restricting the use of chemical methods to remove iron. Even if chemical methods can effectively remove iron, they often lose their economic value due to high costs

[0009] (3) Separation of iron and electrolytic aluminum solid waste by magnetic separation has complex components, and the separation effect of ordinary magnetic separators is not good, while gradient magnetic separation or superconducting magnetic separators have huge investment, high energy consumption and high cost