Method for recovering rare earth, aluminum and silicon from rare earth-containing aluminum and silicon wastes

Abstract

The invention provides a method for recovering rare earth, aluminum and silicon from rare earth-containing aluminum and silicon wastes. The method comprises the following steps: 1, carrying out acid dipping on the rare earth-containing aluminum and silicon wastes by using an aqueous inorganic acid solution to obtain silicon-rich residues and an acid dipping solution containing rare earth ions and aluminum ions; 2, adding an alkaline substance to the acid dipping solution containing rare earth ions and aluminum ions to control the pH value of the acid dipping solution to be 3.5-5.2, and carrying out solid-liquid separation to obtain an aluminum hydroxide-containing precipitate and a rare earth-containing filtrate; and 3, reacting the aluminum hydroxide-containing precipitate with sodium hydroxide to obtain a sodium metaaluminate solution and aluminum and silicon residues, and using the rare earth-containing filtrate to prepare a rare earth compound product. Aluminum and rare earth are dissolved in the acid, segmented alkaline transfer is carried out, the aluminum ions are precipitated to obtain aluminum hydroxide and the rare earth ions which are separated from the aluminum hydroxide, and excess sodium hydroxide is added to convert aluminum hydroxide into the sodium metaaluminate solution, so simultaneous and high-efficiency recycling of the rare earth and aluminum is realized, the use amount of sodium hydroxide is greatly reduced, and the recovery cost is reduced.

Description

technical field [0001] The invention relates to the field of rare earth recovery, in particular to a method for recovering rare earth, aluminum and silicon from rare earth-containing aluminum and silicon waste. Background technique [0002] Rare earth is a general term for 17 elements including lanthanides, scandium and yttrium. The application fields of rare earth elements are very wide, and can be used to prepare fluorescent materials, rare earth metal hydroxide battery materials, electric light source materials, permanent magnet materials and catalytic materials. With the increasing application of rare earth elements in various fields, the consumption of rare earth elements is also increasing. [0003] Rare earth is an indispensable strategic resource for the development of high-tech industries and the transformation of traditional industries. It is recovered from the waste residue generated in the production process of rare earth molecular sieves, waste petroleum cracki...

AI Technical Summary

Problems solved by technology

[0005] The main purpose of the present invention is to provide a method for recovering rare earth, aluminum and silicon from rare earth