Preparation method for high-purity submicron lithium carbonate

Abstract

The invention relates to the technical field of chemical separation and purification, especially to a preparation method for high-purity submicron lithium carbonate. The preparation method comprises the following steps: dissolving a crude lithium carbonate product in high-purity water to prepare lithium carbonate slurry; allowing the lithium carbonate slurry to enter a rotary packed bed and introducing CO2 gas into the rotary packed bed so as to prepare lithium bicarbonate liquid; allowing the lithium carbonate liquid to successively pass through a pretreated calcium-magnesium ion exchange resin apparatus and boron ion exchange resin apparatus so as to allow a second solution to be formed after removal of impurities containing calcium, magnesium and boron in the lithium bicarbonate liquid; uniformly mixing the second solution with a dispersant so as to form a third solution and adding the third solution into the rotary packed bed for a reaction so as to produce lithium carbonate precipitate; and drying the lithium carbonate precipitate so as to obtain a high-purity submicron lithium carbonate product. The preparation method employs crude lithium carbonate of the lithium salt industry as a raw material for preparation of the high-purity submicron lithium carbonate; and the raw material is more widely and easily available and cost for the raw material is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of chemical separation and purification, in particular to a method for preparing high-purity submicron lithium carbonate. Background technique [0002] The preparation of high-purity lithium carbonate usually takes lithium carbonate crude product slurry as raw material, by introducing CO into it 2 A carbonization reaction occurs to obtain a lithium bicarbonate feed solution, which is then subjected to an ion exchange resin removal step, and then a high-purity lithium carbonate product is obtained through a pyrolysis reaction. Therefore, the preparation of lithium bicarbonate feed solution is a necessary process for the preparation of high-purity lithium carbonate. How to improve the conversion efficiency of crude lithium carbonate to lithium bicarbonate process, and shorten this conversion time is a subject that must be considered in the preparation of lithium bicarbonate feed liquid. [0003] In Dai Zhife...

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Problems solved by technology

[0007] 1. Using common methods to complete carbonization to prepare lithium bicarbonate solution, the process takes a long time and has low efficiency

2. To prepare lithium carbonate by pyrolyzing lithium bicarbonate feed liquid, the feed liquid needs to be heated at a constant speed (heating rate is 0.5-1°C / min), heated to 70-90°C, the process consumes a lot of energy, is difficult to control, and the process lasts for a long time long

3. The ion exchange method is used to remove impurities. The ion exchange process does not remove boron in a targeted manner, and boron is a very critical factor affecting the application of lithium carbonate products in battery materials. If the content of boron in raw materials (such as industrial grade lithium carbonate) When it is high, boron cannot be effectively removed by existing technology, which will affect its application as a lithium battery material

The main shortcoming of this prior art has: 1 has special requirement (lithium is soluble lithium salt or soluble lithium hydroxide etc.) to the character of raw material lithium, can not solve the problem that insoluble lithium salt is raw material preparation nano lithium carbonate

Make the application of production technology more limited

2. The dispersant used in the prior art is expensive and the production cost is higher

3 The use of existing technology can only guarantee the standard of lithium carbonate, but cannot meet the product purity of lithium carbonate

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