Method for comprehensively recycling rare earth and fluorine in process of treating bastnaesite

Abstract

The invention provides a method for comprehensively recycling rare earth and fluorine in a process of treating bastnaesite. The method comprises the steps of: carrying out oxidizing roasting on the bastnaesite, leaching a roasted mixture by adopting hydrochloric acid to obtain a rare earth chloride solution containing less cerium and fluorine-containing and cerium-rich slag, wherein a roasting additive is added in the bastnaesite in the roasting process and / or a catalytic leaching additive is added in the mixture in a hydrochloric acid leaching process; and then separating and recycling rare earth chloride from the fluorine-containing and cerium-rich slag. According to the method provided by the invention, the consumption of a large quantity of chemical raw materials can be reduced, the pollution to the environment in a use process is greatly reduced, and the production cost is also greatly lowered. According to the method, the procedures of multiple times of solid-liquid separation and the like are eliminated, the process is simplified, the manipulation strength is reduced, the rare earth loss is reduced, the rare earth yield is increased, and especially the hydrochloric acid leaching recycling rate of high-valent non-cerium rare earth is increased. The method provided by the invention realizes fluorine-free emission in the whole process, and has the characteristics of low consumption, high efficiency and the like.

Description

technical field [0001] The invention relates to a method for comprehensively recovering rare earth and fluorine in the process of bastnaestite treatment, and belongs to the technical field of rare earth hydrometallurgy. Background technique [0002] Bastnaesite is the rare earth mineral resource with the largest reserves and currently the largest amount of mining and use in the world. At present, about 70% of rare earth raw materials are produced from bastnaesite, which is rich in a large amount of fluorine resources. my country is a big country of rare earths, with very rich bastnaesite mineral resources, such as Inner Mongolia Bayan Obo rare earth mine, Sichuan Mianning rare earth mine, Shandong Weishan rare earth mine, etc., all of which are large-scale rare earth deposits dominated by bastnaesite. my country's rare earth production provides 95% of the global rare earth market demand. Sichuan bastnaesite is the second largest rare earth resource in my country. Its smelti...

AI Technical Summary

Problems solved by technology

However, in the process of using this method to treat bastnaesite, there are still a large number of high-value non-cerium rare earths entering the cerium-rich slag, resulting in low-value utilization of high-priced elements. Therefore, steps such as alkali decomposition, washing and hydrochloric acid leaching need to be connected. Bastnaesite The comprehensive utilization of fluorine as an associated resource in the treatment process has not been well resolved; fluorine enters the cerium-rich slag during the hydrochloric acid leaching process, and most of it enters the wastewater with alkali conversion, and its environmental protection treatment is extremely difficult.

For the new emission standards for rare earth industrial production, the widely used hydrochloric acid leaching-alkali conversion-re-optimizing leaching process is difficult to meet the new environmental protection requirements, which requires enterprises to invest more in environmental protection facilities and greatly increase environmental protection treatment costs