Process for producing battery-grade lithium carbonate through processing carbonate type lithium concentrate by deep carbonation method

Abstract

The invention belongs to the technical field of lithium battery materials, and in particular relates to a process for producing battery-grade lithium carbonate through processing carbonate type lithium concentrate by a deep carbonation method. The process comprises grinding, twice ore washing, size mixing, deep carbonation, filtration, calcium removal, pyrolysis, centrifugal separation, washing, drying and smashing as well as carbonized slag recycling. The process principle is as follows: reacting lithium carbonate in the concentrate with carbon dioxide under the conditions of a certain carbon dioxide pressure, reaction temperature and final pH value so as to generate water-soluble lithium dicarbonate; after impurity removal and filtration, removing a part of indissolvable impurities, and dissolving the other part of soluble impurities into a solution; and heating the solution through utilizing the characteristic that lithium dicarbonate is not stable so that lithium dicarbonate is decomposed to generate a lithium carbonate precipitate, separating the lithium carbonate precipitate from the soluble impurities through separation and washing, so as to obtain a lithium carbonate product with required purity. The process is applied to industrial volume production; and the purity of obtained battery-grade lithium carbonate reaches 99.50-99.70%. The process disclosed by the invention is environmentally-friendly, low in energy consumption, low in cost and high in product quality.

Description

technical field [0001] The invention belongs to the technical field of lithium battery material extraction, in particular to a process for producing battery-grade lithium carbonate by treating carbonate-type lithium concentrate with a deep carbonization method. Background technique [0002] In my country's Tibet, there are many salt lakes, rich in lithium, and mainly of carbonate type. After drying the salt, a lithium concentrate containing about 50-75% of lithium carbonate is crystallized. This lithium concentrate also contains a small amount of chloride. and sulfates. According to the mineral phase analysis, the lithium concentrate is mainly composed of lithium carbonate, accounting for about 50-75%; followed by trona, potassium mirabilite, rock salt, and clay minerals accounting for 3-5%; a small amount of natron, quartz, Feldspar, tremolite and other inclusions. Lithium carbonate euhedral-semi-euhedral crystals are rare, most of which are in the form of broken crystals;...

AI Technical Summary

Problems solved by technology

This method needs to consume lime and produce more lithium slag, about 1.8 tons of lithium slag per ton of product, and the causticizing solution must be evaporated and concentrated to increase Li2O from about 18 g / l To 55-60 g / l, it needs to consume more energy. The most important thing is that the lithium carbonate produced by this process can only meet the industrial-grade lithium carbonate standard, and cannot be directly used as a raw material for lithium battery cathode materials

And in order to obtain the battery-grade lithium carbonate that can be used for the positive electrode material of the battery, then industrial grade lithium carbonate must be purified again or industrial-grade lithium hydroxide is carried out carbonization transformation, produces battery-grade lithium carbonate like this and has long technological process, high energy consumption, and slag Large quantity and high cost

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