Method for extracting rare earth and recovering fluorine resource from bastnaesite

Abstract

The invention discloses a method for extracting rare earth and recycling fluorine resources from bastnaesite. The method comprises the following steps that S1, oxidizing roasting is carried out on rare earth concentrate, and then hydrochloric acid leaching is carried out to obtain primary leaching liquid and primary leaching residues; S2, clear water and a hydrochloric acid complexing agent are added into the primary leaching residues, and secondary leaching residues and secondary leaching liquid are obtained after filtering; S3, quenching and tempering and filtering treatment are carried out on the primary leaching liquid and the secondary leaching liquid, and quenched and tempered residues are obtained; and S4, the quenched and tempered residues are dissolved by using hydrochloric acid, filtering and separating are carried out to obtain filter residues, chlorohydric acid pickling is carried out on the filter residues for multiple times, and then drying and packaging are carried out. According to the method, the fluorine resources are recovered by adding the hydrochloric acid complexing agent and the like, alkali conversion is not needed, energy is greatly saved, the production process is simplified, the product cryolite with high added value is formed, due to the fact that high-salt wastewater is not generated, a high-salt recovery system is not needed, the sewage treatment cost is greatly reduced, and the defects in the prior art are overcome.

Description

technical field [0001] The invention relates to the technical field of rare earth hydrometallurgy, in particular to a method for extracting rare earth from bastnaesite and recovering fluorine resources. Background technique [0002] The rare earth ore in Maoniuping, Sichuan is mainly bastnaesite rare earth ore. The content of fluorine in this ore is relatively high. Fluorine generally exists in the form of calcium fluoride or bastnaesium rare earth. Valuable rare earth is actually mainly considering how to separate the fluorine and rare earth in the mine. [0003] At present, domestic manufacturers of bastnaesite mainly adopt the following process: the acid-base combined production process is used to separate the rare earth and fluorine first, and then defluoride the fluorine-containing wastewater. The process currently has the following two major technical defects: one is that the production process is relatively long, the process control requirements are relatively high, ...

AI Technical Summary

Problems solved by technology

The process currently has the following two major technical defects: one is that the production process is relatively long, the process control requirements are relatively high, and the energy consumption and material consumption are relatively large; The obtained waste water has relatively heavy salt content, and the combined acid-base method to treat rare earth concentrates will produce fluorine-containing waste water with high alkalinity. After the fluorine in the waste water is recovered, the salt content in the waste water will be high, usually sodium salt , can reach about 13g / L

[0004] Although the current rare earth industry discharge standards do not have specific requirements for the content of sodium salts, the discharge of high-salt sewage will affect the environment. With the gradual implementation of national policies, the environmental protection pressure of the rare earth industry is increasing, and the discharged wastewater is harmful to high-salt wastewater. The requirements are getting higher and higher. The government's environmental protection department clearly requires the recovery of salt in wastewater, and the salt content can only be discharged within the normal range. Therefore, rare earth enterprises are now required to use high-salt recovery systems.

According to the rare earth enterprises that process 8,000 tons of rare earth concentrates per year, the one-time direct investment of the current high-salt recovery system is about 30 million, not including the operating costs. , the financial pressure is very high, and it also reduces the profit margin of the production enterprise

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