Method for preparing high-purity gadolinium through refining and removing aluminum in rare earth gadolinium solution by ionic liquid method

Abstract

The invention relates to a method for preparing high-purity gadolinium through refining and removing aluminum in a rare earth gadolinium solution by an ionic liquid method, and belongs to the field ofextraction separation. The method is characterized in that functional ionic liquid with a specific structure is used as an extraction agent, an organic solvent is a diluent, an organic phase with selective extraction of the aluminum is formed, and efficient aluminum removal of the rare earth gadolinium solution is realized through cascade extraction. The aluminum content of impurity aluminum ina GdCl3 solution after aluminum removal is less than 10 ppm, the rare earth yield is greater than 99.5%, and the impurity content requirement of the high-purity gadolinium (greater than 4N5) is met. Compared with an existing rare earth solution aluminum removal method, the method has the advantages that saponification is not needed, the process is simple, the cost is low, the aluminum removal efficiency is high, and the rare earth loss is low.

Description

【Technical field】 [0001] The invention relates to a method for preparing high-purity gadolinium by refining rare earth gadolinium solution and removing aluminum, in particular to a method for refining rare earth gadolinium and removing aluminum by an ionic liquid method, which belongs to the field of extraction and separation. 【Background technique】 [0002] The rare earth element gadolinium can form a strong magnetic moment due to its multi-unpaired electronic structure. Significant, intrinsic electronic properties, so the higher the purity of gadolinium is required, the better. Generally, the purity is required to be greater than 99.995%. Solvent extraction is commonly used in industry to extract and purify rare earth gadolinium. In the typical rare earth extraction and separation process of P507-HCl system, the coordination ability of aluminum ions and gadolinium and extraction agent P507 is equivalent, resulting in the impurity aluminum in gadolinium products often excee...

AI Technical Summary

Problems solved by technology

The neutralization method increases the pH value and preferentially precipitates the aluminum ions in the aqueous solution to remove the impurity aluminum in the rare earth. The process is simple and the cost is low. However, due to the close pH value of aluminum hydroxide and rare earth hydroxide precipitation, and the amphoteric nature of aluminum ions Colloids are often formed in aqueous solutions, resulting in difficult filtration and large loss of rare earths, not suitable for the preparation of high-purity gadolinium in addition to aluminum

The extraction method uses the difference in the extraction sequence and distribution coefficient of rare earth and aluminum ions in naphthenic acid extractants to separate aluminum and rare earth. It has the characteristics of continuous process, high rare earth yield and low cost. Commonly used liquid alkali and ammonia water saponification, the naphthenic acid after alkali saponification is soluble in water, resulting in no phase separation, and these saponification agents often contain impurities such as Fe, Si, Ca, Mg and Hg, these new impurities inevitably lead to rare earth Introduction of other impurities in the product

The precipitation method is to use the difference in solubility between rare earth and aluminum oxalate, and the aluminum-containing rare earth solution is subjected to multi-step operations of "oxalic acid precipitation-oxidation roasting-acid dissolution-oxalic acid precipitation-oxidation roasting", but the cost is very high. The loss rate is also very high, and it is difficult for aluminum impurities to reach the standard

Images