Preparation method of lithium carbonate

Abstract

The invention discloses a preparation method of lithium carbonate. The preparation method comprises the steps of size mixing, neutralization and leaching, alkalization and impurity removal, slag treatment, concentration and filtration, ion exchange, lithium precipitation, primary product washing and separation and drying. According to the method, many defects of the existing sulfuric acid method for producing lithium carbonate are overcome, and the leaching rate of lithium, the impurity removal and purification effect of the lithium sulfate solution, the conversion rate of lithium precipitation reaction and the lithium yield are effectively improved through combined application of the ultrasonic technology; the lithium yield of the whole process is further improved through recovery of lithium in the leaching residues and the alkalization residues and reuse of the heat-out mother liquor generated in the preparation process of the byproduct sodium sulfate. The method is simple in process, convenient to operate and high in industrial feasibility; the lithium yield is greater than 95%, the product purity is high, the quality is stable, and the standard of battery-grade lithium carbonate products in the industry is reached.

Description

technical field [0001] The invention belongs to the technical field of lithium resource extraction, and in particular relates to a method for preparing lithium carbonate by using acid clinker after acidification and roasting of lithium ore as a raw material. Background technique [0002] The production technologies for preparing lithium carbonate from spodumene mainly include sulfuric acid method, chlorination roasting method and pressure cooking method. Due to the serious pollution of the chlorination roasting method, and the removal of chloride ions during subsequent product purification is more complicated. The process of pressure cooking is complicated, the safety risk is high, and the waste residue produced cannot find a suitable use. At present, the sulfuric acid method is mainly used for the large-scale production of lithium carbonate. [0003] Extracting lithium carbonate from spodumene by sulfuric acid method is a relatively mature lithium extraction technology, a...

AI Technical Summary

Problems solved by technology

Due to the complex chemical composition and many impurities (including insoluble and insoluble substances) in the acid clinker after acidification and roasting of spodumene, there are agglomeration and mutual wrapping phenomena, resulting in part of the lithium not being leached, but remaining in the filter residue.

During the purification process of the leachate, the coated impurity cannot be removed by chemical precipitation. When the leachate reacts with sodium carbonate to prepare lithium carbonate, on the one hand, the lithium covered by the impurity fails to participate in the lithium precipitation reaction, resulting in a low conversion rate of the reaction. The lithium yield of method has only 82~86% (CN 113003590A, a kind of method for making lithium carbonate by thermal reduction of spodumene); On the other hand, sulfate radical, potassium, sodium etc. will be partly wrapped by lithium carbonate and cannot be removed, resulting in The impurity content such as sulfate radical, potassium, sodium is higher in the gained lithium carbonate product (CN 110078099 A, a kind of method for preparing lithium carbonate from lepidolite leaching purification liquid; Sulfate content technology)

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