Magnetic selection method for electrolytic aluminum waste material

Abstract

The invention discloses a magnetic selection method for an electrolytic aluminum waste material. The electrolytic aluminum waste material is subjected to wet-type breakage and floating selection. The method is characterized by comprising the following steps of: adding a reducing agent into the electrolytic aluminum waste material; converting the surface of a hematite-contained particle in the waste material into magnetite; and removing ferrum and silicon in magnetic selecting equipment and separating to obtain carbon powder and other raw materials. The hematite (Fe2O3) on the surface of an impurity particle is converted into the magnetite (F3O4) with strong magnetism by utilizing the trace reducing agent in the process of floating selection, the effect of the magnetic selection is greatly improved, and the effect of a gradient magnetic separator can be achieved by adopting a common magnetic separator. Then, the initially separated carbon powder is subjected to alkali type dissolving, the cryolite (Na3AlF6) is separated, and the processed carbon powder (ash content being 1-2 percent) reaches the grade of high-purity carbon powder and greatly improves the market value of products.

Description

technical field [0001] The invention relates to a magnetic separation method for 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 domestic large-scale 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 re...

AI Technical Summary

Problems solved by technology

However, the separated carbon powder mainly contains iron, silicon, 6%-12% cryolite (Na 3 AlF 6 ), iron and silicon must be removed as harmful impurities, cryolite (Na 3 AlF 6 ) is a reusable product. If it cannot be separated and purified, it cannot meet the requirements of industrial applications. It can only be sold as a general combustion aid, and its market value is very low.

[0006] In the prior art, for impurities such as iron and silicon in electrolytic aluminum waste, one is to remove iron (Fe) through chemical methods, and a considerable part of the iron in the waste exists in the form of iron fluoride salts, and fluoride salts have The high stability of iron is the key technical bottleneck restricting the use of chemical methods to remove iron. Even if the existing chemical methods can effectively remove iron, they often lose their economic value due to high costs.

[0007] The second is to separate iron by magnetic separation, but the components of electrolytic aluminum solid waste are complicated, and the separation effect of ordinary magnetic separators is not good, while gradient magnetic separation or superconducting magnetic separators require huge investment, high energy consumption, and high costs