A liquid alkali decomposition method of high-grade mixed rare earth concentrate

Abstract

The invention relates to a liquid alkali decomposition method of high-grade mixed rare earth ore concentrate. The liquid alkali decomposition method of the high-grade mixed rare earth ore concentrate is characterized by comprising the steps: mixing the high-grade mixed rare earth ore concentrate with REO being more than 60 percent by weight and a sodium hydroxide with the concentration being more than 60 percent by weight and performing reaction on the mixed slurry at 150 to 160 DEG C for 0.2 to 1 hour, wherein the weight ratio of the mixed rare earth ore concentrate to the sodium hydroxide is 1:(3.5-7.5); after reaction is finished, performing hot filtration at the temperature being more than 60 DEG C and washing an alkali cake obtained by filtration with water until the pH value is 7; and dissolving the alkali cake which is washed until the pH value is 7 with hydrochloric acid of 6 to 10 mol / L and controlling the pH value to be 4 to 5 to obtain a pure rare earth chloride solution. The liquid alkali decomposition method of the high-grade mixed rare earth ore concentrate has the advantages that high-concentration liquid alkali reaction is conducted under the condition of high alkali-ore ratio, so the system is high in flowability, small in alkali concentration change, high in reaction temperature, insusceptible to fluctuation and short in reaction time, continuous production is realized easily, the problem about continuous industrial production of the liquid alkali decomposition process of the high-grade mixed rare earth ore concentrate is solved, and continuous production of the alkali decomposition process is realized.

Description

technical field [0001] The invention relates to a liquid alkali decomposition method of high-grade mixed rare earth concentrate, belonging to the field of rare earth hydrometallurgy. Background technique [0002] Mixed rare earth concentrates account for more than 60% of my country's smelting rare earth concentrates. The current industrial application of alkaline decomposition mixed rare earth concentrate process is: first dissolve and remove calcium with hydrochloric acid, then wash the excess acid with water, then decompose with liquid alkali, then wash the excess alkali and the soluble salt formed, and finally dissolve the hydrochloric acid to obtain rare earth chloride solution. In this process, the ore-soda ratio of rare earth concentrate and sodium hydroxide is generally 1:0.5~1.5, and sodium hydroxide is configured into a solution with a concentration of 50%~60%, and the slurry is thick after mixing the concentrate and sodium hydroxide solution It has a high tempera...

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Problems solved by technology

[0003] The purpose of the present invention is to solve the problem of continuous industrial production of high-grade rare earth concentrate liquid alkali decomposition, shorten the process flow and realize the recovery of resources such as rare earth, thorium, fluorine and phosphorus, and provide a liquid solution of high-grade mixed rare earth concentrate Alkali decomposition method, this method is to carry out high-concentration liquid alkali reaction under the condition of high alkali-mineral ratio, the fluidity of the system is good, the change of the alkali concentration of the system is small, the reaction temperature is high and not easy to fluctuate, the reaction time is short, and it is easy to realize continuous production; The invention can make the alkali decomposition process realize continuous industrial production

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