Extraction and purification method for thulium oxide

Abstract

The invention discloses an extraction and purification method for a thulium oxide. The method comprises the steps of preparation of liquid to be purified, intermediate agent preparation, separation column preparation, elution column transformation, adsorption operation, elution ion exchange operation, collection of liquid according to the volume for sampling analysis, concentrated sedimentation, mixing and collection, waste liquid processing and the like. The existing roughly-processed collected low-purity thulium oxide is purified again, and the purity of the thulium oxide reaches 99.995%-99.99999%.

Description

technical field [0001] The invention relates to a method for separating, extracting and purifying rare earth oxides, in particular to a method for extracting and purifying thulium oxide with a purity of 99.9%-99.99%. Background technique [0002] Rare earths are composed of 15 lanthanide elements (lanthanum La cerium Ce promethium Pm praseodymium Pr neodymium Nd samarium Sm europium Eu gadolinium Gd terbium Tb dysprosium Dy holmium Ho erbium Er thulium Tm lutetium Lu) and scandium Sc yttrium Y a total of 17 elements, of which promethium Pm does not exist in nature, scandium Sc has very little content in rare earth ores, and generally only 15 other elements are contained in rare earth ores. Since the properties of various rare earth elements are very similar, it is difficult to separate them. [0003] There are many types of rare earth minerals. At present, bastnaesite, monazite, ion-adsorbed rare earth ore and xenotime are mainly used in industry. The commonly used treatmen...

AI Technical Summary

Problems solved by technology

[0005] Two processes are currently used for the separation and extraction of rare earths from mixed sulfuric acid rare earth solutions: one is to use ammonium bicarbonate precipitation transformation to produce rare earth carbonate, and then dissolve it in hydrochloric acid and extract and separate it with ammonia soap P507. This process produces a large amount of Ammonia nitrogen wastewater. According to statistics, Baotou area produces millions of tons of this kind of wastewater every year. The ammonia nitrogen content in the wastewater is 5-10g / L, which exceeds the national secondary discharge standard (25mg / L) by hundreds of times, resulting in serious water pollution. Nutritization, the wastewater is difficult to recover due to its dilute concentration and complex system. In addition, the solution needs ammonium bicarbonate precipitation-hydrochloric acid dissolution transformation, and the consumption of chemical materials

[0006] Another process is to add sulfuric acid rare earth solution to sulfuric acid to adjust the acidity to 0.2mol / L, directly use P204 (D2EHPA, bis(2-ethylhexyl phosphate) to carry out Nd / Sm extraction and grouping, and the raffinate is neutralized to remove acid After that, use P204 total extraction-hydrochloric acid back extraction to obtain a high-concentration LaCePrNd rare earth chloride solution (Chinese patent CN80105043.6), and then use ammonia soap P507 to extract and separate a single rare earth. However, P204 has a strong extraction ability under acidic conditions. When the acidity of the feed liquid is low, it is easy to emulsify. A certain amount of acid needs to be added during extraction. The grouped raffinate needs to be neutralized and filtered. The residual acid in the extract is high, the acid consumption is large, the concentration of rare earth sulfate is low, and the Nd / Sm extraction grouping tank is large

[0007] At present, ion exchange chromatography technology is still used in the market for the separation and purification of single rare earth, but the ordinary ion exchange production cycle is long, the cost is high, and the purity can only reach 99.99% of the product, which cannot meet the needs of the market