Process for producing granular rare earth chloride crystals by using rare earth chloride solution

Abstract

The invention relates to a process for producing granular rare earth chloride crystals by using a rare earth chloride solution, which belongs to the field of rare earth hydrometallurgy. According to the invention, a hydrochloric acid is added into the rare earth chloride solution, and after the pH value of the obtained mixture is 1-3, the obtained mixture is evaporated, so that the mass concentration of the obtained mixture is increased to 700-750g/L; water vapor and escaped hydrogen chloride gas are condensed and then recycled; the solution subjected to evaporation enters a cooling system through self-flowing, so that the solution is cooled to room temperature and crystallized; then the crystallized solution is fed into a centrifugal machine to carry out solid-liquid separation; and mother liquor is recycled, and solids are granular rare earth chloride crystals. According to the invention, a hydrochloric acid is added into the rare earth chloride solution to adjust the pH value, so that the impurity content of products is low; through concentration control, granules are uniform and stable in quality; the process method is simple in operation, short in production cycle and serialized; the rare earth content of produced granular rare earth chloride crystals can reach 62-67%; and escaped hydrogen chloride steam and water vapor, after recovered by a condensing system, is reused, therefore, an effect of industrialized production is easily achieved.

Description

technical field [0001] The invention relates to a rare earth chloride solution used for the production of granular rare earth chloride crystals, and belongs to the field of rare earth hydrometallurgy. technical background [0002] According to the literature, the hydrated rare earth chloride crystallizes under vacuum conditions (the material is static) and removes all the crystallization water at a temperature of 200 °C. When the heating temperature is 200-280 ℃, all the water of crystallization will be removed. In the mid-1970s, rare earth chloride solution was directly sprayed and dehydrated in China to prepare powdery anhydrous rare earth chloride. [0003] At present, the preparation of anhydrous rare earth chloride in China generally uses the rare earth chloride solution after pretreatment of Baotou rare earth concentrate and monazite concentrate, and carries out four processes including decompression concentration cooling crystallization, manual crushing and vacuum de...

AI Technical Summary

Problems solved by technology

Its rare earth chloride crystals contain 52%-58% of rare earths, and the product quality is unstable. The hydrogen chloride gas and water vapor gas generated in the process cannot be recovered, causing serious pollution to the environment; this process is long, intermittently operated, and labor-intensive. Unstable product quality is not good for improving current efficiency