Method for producing rare earth ferro-silicon raw material with fluorine containing alkali waste water

Abstract

The invention relates to a wastewater treatment method during the rare-earth hydrometallurgy process, which obtains products that can be used as the material for smelting rare-earth silicoferrite. The method comprises the steps as follows: the rare-earth is acid-dipped, the slurry is stirred and mixed after being added with water; salt solution containing metal ions is added; fluorine-containing waste alkaline water is added in the mixture to form fluoride and hydroxide precipitate, and the addition amount is controlled according to the precipitated metal ion amount that is 10wt percent to 95wt percent; other precipitators are added in sequentially to precipitate the metal ions fully; water is added for washing until the pH value ranges from 7 to 8; solid is dried and dewatered at the temperature that ranges form 110 to 600 DEG C after solid-liquid separation; products can be used as the material for smelting the rare-earth silicoferrite after dehydration. In the waste water discharged in wastewater treatment method, the content of fluorine ion is less than 10mg / L, the pH value ranges from 8 to 9, and the waste water is neutral.

Description

Technical field [0001] The present invention relates to a method for treating wastewater in the rare earth hydrometallurgical process, and the product obtained by this treatment method can be used as a raw material for rare earth ferrosilicon. Specifically, it relates to a method for preparing rare earth ferrosilicon raw materials from fluorine-containing waste alkali water. method. Background technique [0002] Bastnaesite is a resource dominated by light rare earths. Its rare earth reserves are second only to Baotou Bayan Obo and the Mountain Pass Mine in the United States. It is the third largest rare earth resource in the world. Its development and application play a vital role in the application of rare earths and the economic development of western my country. [0003] For the decomposition method of bastnasite, the hydrochloric acid method is currently the most widely used, and the sulfuric acid method is rarely used. There are many literature reports on the specifi...

AI Technical Summary

Problems solved by technology

The second method is first acid-dissolving and then alkali-transforming. For example, the method in the Chinese invention patent with the publication number CN1683569 A is that bastnaesite is oxidized and roasted and then dissolved with hydrochloric acid. The slag after fluorine is acid-soluble again, and by controlling the addition conditions of hydrochloric acid, the cerium-rich lanthanum feed solution and 95% cerium oxide product can be obtained respectively; Water washing to remove fluorine, but the conditions are simple, and finally only a primary product of mixed rare earth chloride is obtained

[0009] 1. Recovering alkali by electrolysis: as introduced in patents CN1715199A and CN1554591A, but alkali conversion wastewater contains a large amount of F, which leads to alkali pollution

[0010] 2. Waste slag adsorption and biodegradation soil pit storage: as described in the patent CN1059322A, the method is essentially to soak the waste alkaline water with industrial waste and waste slag and then use it as agricultural soil or earth pit to bury it, which requires a large amount of space, a long cycle, and processing The amount is small and cannot be handled F -

[0011] 3. Other methods such as concentration, acid analysis, alkali reduction (CN1078184C) etc. also have their limitations and cannot solve the problem of F - The problem

[0012] None of the above methods can effectively treat the alkali-to-alkali wastewater produced in the existing rare earth production, resulting in serious pollution