Method for preparing mixed rare earth carbonate by using mixed precipitant in sulphuric acid system

A technology of mixed precipitation and rare earth carbonate, applied in the direction of improving process efficiency, can solve the problems of high treatment cost of precipitation wastewater, low concentration of precipitant, and large amount of precipitation wastewater, so as to save treatment costs and heating costs, reduce emissions, reduce The effect of output

Inactive Publication Date: 2018-03-06
CHINA NORTHERN RARE EARTH (GROUP) HIGH TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the application of this process, due to the low solubility of ammonium bicarbonate, the concentration of the precipitant prepared is low, so more precipitation wastewater is produced, resulting in

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0025] Example 1

[0026] Under constant stirring, mix the solid ammonium bicarbonate with industrial-grade ammonia at a molar ratio of 6:4 and add water at 20°C to make the concentration of the mixed precipitation agent 5mol / L. 1.65m 3 Precipitating agent and 0.4t mixed rare earth carbonate are added as seed crystals to the reaction tank. Under constant stirring and controlling the temperature of the solution in the reaction tank to 35°C, the mixed rare earth sulfate (REO=0.1789mol / L) solution is slowly added to the reaction tank The adding time is 4h, and the adding amount makes the pH of the solution 6.7. After the precipitation is over, it is aged for 2 hours under the conditions of constant stirring and a temperature of 30°C. The quality index of the mixed rare earth carbonate obtained after filtration and washing of the precipitate is: REO=43.64%, SO 4 2- / REO=2.64%, the output of sedimentation wastewater is 34.8m 3 / tREO.

Example Embodiment

[0027] Example 2

[0028] Under constant stirring, mix the solid ammonium bicarbonate with the industrial-grade ammonia water at a molar ratio of 5.6:4.4, and then add water at 26°C to make the concentration of the mixed precipitation agent 5.5mol / L. 1.5m 3 Precipitating agent and 0.6t mixed rare earth carbonate are added as seed crystals to the reaction tank, and the temperature of the solution in the reaction tank is continuously stirred and controlled to 30°C. The mixed rare earth sulfate (REO=0.1789mol / L) solution is slowly added to the reaction tank The adding time is 5h, and the adding amount makes the pH of the solution 6.7. After the precipitation is over, aging for 0.5h under the conditions of constant stirring and a temperature of 40°C, the quality index of mixed rare earth carbonate obtained after filtration and washing of the precipitate is: REO=44.26%, SO 4 2- / REO=2.42%, the output of sedimentation wastewater is 34.6m 3 / tREO.

Example Embodiment

[0029] Example 3

[0030] Under constant stirring, mix the solid ammonium bicarbonate with industrial-grade ammonia water at a molar ratio of 6:4 and add water at 25°C to make the concentration of the mixed precipitation agent 4.5mol / L. 1.8m 3 Precipitating agent and 0.6t mixed rare earth carbonate are added as seed crystals to the reaction tank, and the temperature of the solution in the reaction tank is continuously stirred and controlled to 30°C. The mixed rare earth sulfate (REO=0.1983mol / L) solution is slowly added to the reaction tank The adding time is 3h, and the adding amount makes the pH of the solution 6.7. After the precipitation is over, aging for 1 hour under the conditions of constant stirring and a temperature of 35°C, the precipitate is filtered and washed to obtain the quality index of mixed rare earth carbonate: REO=44.52%, SO 4 2- / REO=2.54%, the output of sedimentation wastewater is 31.7m 3 / tREO.

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Abstract

The invention discloses a method for preparing mixed rare earth carbonate by using a mixed precipitant in a sulphuric acid system. The method comprises the following steps: with continuous stirring, mixing ammonium bicarbonate and industrial-grade ammonia water in the molar ratio of 5.6:4.4-10:1, and adding water at 15-30 DEG C to enable the concentration of the mixed precipitant to be 3 to 7 mol/L; placing the mixed precipitant and a seed crystal into a reaction tank, wherein the seed crystal is the mixed rare earth carbonate which is produced by taking mixed sulphuric acid rare earth solution as a raw material; with continuous stirring, controlling the temperature of the solution in the reaction tank to be 20-50 DEG C, and slowly adding the mixed sulphuric acid rare earth solution into the reaction tank, wherein the adding time is 2 to 6 hours, and the using amount enables the pH of the solution equal to be 6.5-7; after the ending of precipitating, aging for 0.5-2 hours at the temperature of 30-50 DEG C with stirring; filtering and washing a precipitant to obtain the mixed rare earth carbonate and ammonium sulphate-containing precipitation wastewater. According to the method, theoutput quantity of the precipitation wastewater can be reduced.

Description

technical field [0001] The invention relates to a rare earth hydrometallurgy technology, in particular to a method for preparing mixed rare earth carbonate by using a mixed precipitant in a sulfuric acid system. Background technique [0002] At present, concentrated sulfuric acid high-temperature roasting method is mostly used in the decomposition of Baotou rare earth concentrate, and the mixed rare earth sulfuric acid solution produced is purified and precipitated with ammonium bicarbonate solution. The method for industrialized production of mixed rare earth carbonate is to add ammonium bicarbonate solid into water at a temperature of 45-55° C., and prepare a 2.0-2.8mol / L ammonium bicarbonate solution as a precipitant and mixed rare earth sulfate (REO=0.1539-0.2012mol / L) solution reaction. After the reaction is completed, the mixed rare earth carbonate can be obtained after the slurry is filtered and washed, the total amount of rare earths (REO) is between 43% and 46%, a...

Claims

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Application Information

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IPC IPC(8): C22B3/44C22B59/00
CPCC22B3/44C22B59/00Y02P10/20
Inventor 赵治华桑晓云刘瑞金张正中张文斌邢全生魏迪张国光张升强王喜刚李旭徐占宇
Owner CHINA NORTHERN RARE EARTH (GROUP) HIGH TECH CO LTD
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