Treatment method for rare earth phosphate rock and enrichment method for rare earth

Abstract

The invention discloses a treatment method for a rare earth phosphate rock and an enrichment method for rare earth. The treatment method comprises the following steps: mixing the rare earth phosphate rock and phosphoric acid to form mixed slurry; adding concentrated sulfuric acid into the mixed slurry in such a manner that the concentration of Ca<2+> in the mixed slurry is decreased from at least 1 wt% to the equilibrium concentration of Ca<2+> and SO4<2->, then the concentration of SO4<2-> in the mixed slurry is increased from the equilibrium concentration of Ca<2+> and SO4<2-> to at least 2 wt% and the mixed slurry is added during addition of the concentrated sulfuric acid to allow the rare earth phosphate rock to be dissolved so as to obtain hemihydrate gypsum; and subjecting the obtained hemihydrate gypsum to recrystallization to obtain dihydrate gypsum. The enrichment method for rare earth comprises a step of recovering rare earth elements from liquid obtained after recrystallization of the hemihydrate gypsum and / or liquid obtained after heating of the mixed slurry. In the process of generation of the hemihydrate gypsum, the addition speed of the concentrated sulfuric acid is controlled, and SO4<2-> in the mixed slurry is allowed to be insufficient at first and then controlled to be excess, which aids rare earth in entering into the phosphoric acid.

Description

technical field [0001] The invention relates to an ore processing method, in particular to a processing method for rare earth phosphate rock and a method for enriching rare earth. Background technique [0002] In addition to the occurrence of rare earth in various rare earth ores, a considerable part of the rare earths in nature is symbiotic with apatite and phosphorite ores. The ionic radius of rare earth (0.848~0.106nm) and Ca 2+ (0.106nm) is very close. In phosphate rock, rare earths occur in phosphate rock in the form of isomorphism. With the P 2 o 5 As the grade increases, the content of rare earth elements increases, and the two show a positive and negative relationship. [0003] In the prior art, the methods for recovering rare earths from phosphate rock are mainly divided into wet method and thermal method. In the wet method, it can be divided into nitric acid method, hydrochloric acid method and sulfuric acid method according to the different decomposition acids...

AI Technical Summary

Problems solved by technology

Because decomposing monazite requires relatively harsh conditions, such as higher temperature and pH, etc., when using the sulfuric acid method in the prior art to wet process phosphate rock containing monazite, it is often impossible to take into account the complete decomposition of monazite while improving The enrichment degree of rare earth in phosphoric acid is not conducive to the recovery of rare earth elements in subsequent processes

Moreover, it is difficult to achieve effective separation of rare earth independent minerals and phosphate rock during the beneficiation process.

[0008] In short, there are still technical and economic problems in the recovery of trace rare earth elements in complex rare earth phosphate rocks