Method for precipitating rare earth by adopting carbon dioxide

Abstract

The invention relates to a method for precipitating rare earth by adopting carbon dioxide. The method comprises the following steps of: (1) preparing an extracting agent solution; (2) precipitating rare earth salts by using carbon dioxide, wherein in order to solve the problem that rare earth precipitates carry the extracting agent solution in the process of the precipitating rare earth salts by using the carbon dioxide, the step can also adopt the process of generating bicarbonate firstly and then indirectly precipitating the rare earth salts; (3) separating the aqueous phase of the rare earth salts precipitated by the carbon dioxide to obtain a salt solution which can be recycled, wherein solid is rare-earth carbonate; and (4) obtaining an organic phase which is an extracting agent solution extracting acid, wherein the extracting agent solution after reacting can be recycled. The invention has great innovation in the aspects of cost saving and environmental protection and greatly overcomes the defects of high cost and severe ammonia nitrogen and salt pollution of a traditional rare earth precipitation method. Salts in waste water in a rare earth separation process are used as salts used in the precipitating process for recycling, thereby realizing zero drainage of industrial waste water, replacing a traditional ore dissolving process and most sufficiently utilizing a process intermediate product.

Description

technical field [0001] The invention relates to a rare earth precipitation method, in particular to a rare earth precipitation method using carbon dioxide. Background technique [0002] my country has the most abundant rare earth mineral resources in the world. In the process of rare earth separation and production, it is necessary to precipitate the rare earth salt solution into rare earth carbonate solids and calcinate them into rare earth oxide products. The traditional precipitation method is to use sodium bicarbonate, sodium carbonate or ammonium bicarbonate as a precipitant in a rare earth salt solution. The above-mentioned precipitating agent is expensive, and a large amount of waste water is generated in the above-mentioned precipitation process, which seriously pollutes the environment. At the same time, in the rare earth separation process, the saponification process using saponification agents such as ammonium hydroxide and sodium hydroxide will generate wastewat...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to address the shortcomings of the above-mentioned rare earth precipitation method, such as high cost and serious ammonia nitrogen pollution, to develop a method for precipitation of rare earth using carbon dioxide, which has low raw material prices, simple process flow, avoids waste water discharge, and greatly reduces costs; The salt in the above wastewater can be used for recycling, realizing zero discharge of industrial wastewater