Technique for extracting and separating rare earth elements from non-saponification system

Abstract

This invention provides a process for extracting and separating rare earth elements by using non-saponification extractant. The process comprises: utilizing rare earth sulfate solution containing two or more rare earth elements obtained by treating rare earth ore as the raw material, performing Nd / Sm multi-stage fractionation and extraction by using non-saponification extractant P507 to obtain Sm / Eu / Gd enriched product and La / Ce / Pr / Nd extraction raffinate, and further extracting and separating rare earth compounds with non-saponification extractant. The process has such advantages as no emulsification under low-acidity extraction, easy back extraction of medium-molecular-weight rare earth elements, low acid consumption, and high productivity.

Description

technical field [0001] The invention relates to a process for extracting and separating rare earth elements. Specifically, the rare earth sulfate solution containing at least two rare earth elements obtained from the treatment of rare earth ores is used as a raw material, and non-saponified P507 is used for neodymium / samarium extraction grouping to obtain samarium europium gadolinium enrichment and lanthanum cerium praseodymium neodymium raffinate. Then use non-saponifiable P204 or non-saponifiable P204 and non-saponifiable P507, C272, C301, C302, HEOPPA, P350, TBP one or two of the mixed extraction agent prepared in the lanthanum cerium praseodymium neodymium sulfate and chloride A process for extracting and separating rare earth elements from a mixed solution of rare earth or rare earth nitrate. Background technique [0002] Lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lut...

AI Technical Summary

Problems solved by technology

The first and second methods have good separation effects and are widely used, but they must be saponified with ammonia water or ammonium bicarbonate, which will produce a large amount of ammonia nitrogen wastewater and cause great pollution to the environment.

The third method is the process adopted by France Rhodia and American Molybdenum Company. It is derived from the rare earth nitrate solution obtained when processing monazite ore to separate rare earth. The concentration of nitric acid in the extraction system of this process is high, so the production cost is high. stop state

The fourth process was invented by Beijing General Research Institute of Nonferrous Metals. It is applied to the extraction and separation of rare earth elements from the sulfuric acid rare earth solution obtained from the sulfuric acid roasting method to treat Baotou rare earth mines. The alkali consumption is less, but due to the low concentration of rare earth in the sulfuric acid system (<45g / L), the investment in the equipment extraction agent is large, and P204 has a strong extraction ability under acidic conditions. When the acidity of the feed liquid is low, it is easy to emulsify, and a certain amount of acid, while medium and heavy rare earth stripping is very difficult, the residual acid in the stripping liquid is high, and the acid consumption is large