Method for preparing rare earth oxide from rare earth polishing powder waste

Abstract

The invention relates to a method for preparing rare earth oxide from rare earth polishing powder waste. The method is characterized in that the rare earth polishing powder waste is subjected to alkali roasting and washed acidification for decontaminating and is precipitated, filtered, washed and dried to obtain a rare earth oxide finished product. Acidified filtrate is precipitated and filtered for decontaminating and is burnt to obtain the rare earth oxide finished product. The method has the advantages that acids, such as hydrogen fluoride and nitric acid great harm to the environment are not used, the recycling process is pollution-free, the rare earth polishing powder waste is reasonably utilized comprehensively, the rare earth recovery ratio achieves more than 90%, and the rare earth oxide finished product with the purity of more than 95% can be prepared. Alkali and acid wastewater can be recycled after treatment, the rare earth polishing powder waste is utilized comprehensively, and the entire recovery process is environmentally-friendly and pollution-free.

Description

technical field [0001] The invention belongs to the technical field of material preparation, and in particular relates to a method for preparing rare earth oxide from rare earth polishing powder waste residue. Background technique [0002] Because of its unique physical and chemical properties, rare earth polishing powder is widely used in fine grinding of display screens, optical glass, accessories, building materials, molds and precision instruments. According to statistics, in 2011, the output of rare earth polishing powder in my country was 15,500 tons (physical volume), the output of legal rare earth mines was 84,900 tons (REO), and the actual consumption of rare earth polishing powder was about 13,950 tons (REO), accounting for 16.43% of the mandatory plan. . The application of rare earth polishing powder was 4800t (REO), an increase of 4.35% over the previous year. With the increase of the application amount of rare earth polishing powder, the solid waste of rare ear...

AI Technical Summary

Problems solved by technology

Its main components are rare earth oxides containing lanthanum and cerium, ground glass particles, abrasive skin (organic polymer) on the polishing machine, and artificially mixed precipitant aluminum chloride in the waste liquid, etc. The rare earth in these waste residues Elements are difficult to recycle and reuse in a simple way, resulting in a waste of rare earth resources

[0004] At present, there have been reports on the recycling of rare earth polishing powder slag at home and abroad. The Japanese patent JP11319F55 and the domestic patent "Regeneration method of invalid rare earth polishing powder" use hydrofluoric acid or fluoride to remove the glass component in the waste slag, so as to achieve the purpose of recycling. , not only the process is complicated, but also the post-treatment of fluoride and environmental pollution problems will be brought

The domestic patent "A method for preparing lanthanum cerium oxalate from rare earth polishing powder waste residue" adopts sulfuric acid to leaching the waste residue to recover rare earth elements. limitation