Method for preparing high-purity mixed rare earth chloride by sulfuric acid rare earth water leaching liquid neutralization, impurity removal and recycling

Abstract

The invention discloses a method for preparing a high-purity mixed rare earth chloride by sulfuric acid rare earth water leaching liquid neutralization, impurity removal and recycling. The method comprises the steps that mixed rare earth ore concentrate is subjected to concentrated sulfuric acid high-temperature roasting and water leaching, then water leaching slag and slurry clear liquid are obtained, and the temperature of the slurry clear liquid is less than or equal to 40 DEG C; the slurry clear liquid is neutralized with a neutralizing agent to a pH of 3.8-4.5, separation is carried out,and water leaching liquid and neutralization slag are obtained; the water leaching liquid is subjected to ammonia precipitant cocurrent flow precipitation and prepared into a mixed alkaline rare earthcompound so as to obtain ammonium sulfate wastewater and the mixed alkaline rare earth compound; and mixed rare earth carbonate in the mixed alkaline rare earth compound is subjected to hydrochloricacid dissolution and transformed into the high-purity mixed rare earth chloride suitable for extraction and separation. The problems of sulphate crystallization in the sulphuric acid rare earth slurryclear liquid neutralization calcium-and-magnesium removal and sulphate wastewater concentration process and ammonia double salt precipitation of sulfuric acid rare earth in the ammonia neutralizationand precipitation process are solved.

Description

technical field [0001] The invention relates to a hydrometallurgical technology, in particular to a method for neutralizing and removing impurities in a sulfuric acid rare earth immersion solution and circulating to prepare a high-purity mixed rare earth chloride. Background technique [0002] The mixed rare earth concentrates in Baotou area are mainly processed by concentrated sulfuric acid high-temperature roasting process. The process includes mixed high-temperature roasting of rare earth concentrates and concentrated sulfuric acid, water leaching, magnesium neutralization and impurity removal, transformation (carbon precipitation or extraction) and other links. Although the process is simple and has strong applicability to mineral grades, it also has the problem of "three wastes" that are difficult to deal with, and among the "three wastes" is the problem of wastewater. [0003] In the current production process, in the process of extracting rare earth minerals into rare...

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Problems solved by technology

[0005] The technical problem solved by the present invention is to provide a method for neutralizing and removing impurities in rare earth sulfate water immersion liquid and circulating to prepare high-purity mixed rare earth chloride, which solves the process of neutralizing rare earth sulfate pulp clear liquid, removing calcium, magnesium, and sulfate wastewater The crystallization of sulfate in medium, and the precipitation of rare earth ammonium sulfate double salt in the process of ammonia neutralization and precipitation

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