Preparation method for ultrapure ultrafine cobalt carbonate

Abstract

The invention provides a preparation method for ultrapure ultrafine cobalt carbonate. The preparation method comprises the following steps: (1) adding a base reaction solution into a reaction vessel, adding a carbonate solution or bicarbonate solution and a cobalt salt solution into the base reaction solution, and carrying out a reaction under stirring so as to obtain slurry containing cobalt carbonate, wherein a mol ratio of carbonate or bicarbonate to cobalt ions in the cobalt salt is (3.0-6.0): 1, the pH value of a reaction system is 6.8 to 8.2, reaction temperature is 25 to 80 DEG C and reaction time is 0.5 to 3 h; (2) subjecting the slurry containing cobalt carbonate to solid-liquid separation so as to obtain a filter cake, conveying the filter cake to a slurrying tank for slurrying so as to obtain a slurried material, conveying the slurried material to a washing tank for washing at a constant temperature and carrying out solid-liquid separation after completion of washing so as to obtain a cobalt carbonate precipitate; and (3) drying, crushing and sieving the cobalt carbonate precipitate so as to obtain ultrapure ultrafine cobalt carbonate. The preparation method provided by the invention is low in cost, simple in process flow and easy to operate.

Description

technical field [0001] The invention belongs to the technical field of metal particle preparation, and in particular relates to a method for preparing ultra-pure and ultra-fine cobalt carbonate. Background technique [0002] Cobalt carbonate is one of the precursors for preparing cobalt powder, and its physical and chemical properties directly affect the application of cobalt powder. In order to obtain cobalt powder with good performance, there are generally strict restrictions on the content of impurities in cobalt carbonate. For example, the requirements for the content of impurities in battery-grade cobalt carbonate are: Cl content is less than 0.01%, Na content is less than 0.01%, and Ca content is less than 0.01%. , Mg content is less than 0.01%, Fe content is less than 0.005%. However, due to the small particle size and large specific surface area of ​​cobalt carbonate, it is difficult to filter, wash and dry after synthesis, so it is often difficult to balance the ul...

AI Technical Summary

Problems solved by technology

However, due to the small particle size and large specific surface area of ​​cobalt carbonate, it is difficult to filter, wash and dry after synthesis, so it is often difficult to balance the ultra-pure and ultra-fine properties of cobalt carbonate

For example, in the invention with the publication number CN103922426A, add ammonium bicarbonate with 4-6 times the amount of cobalt chloride to precipitate cobalt, wash after aging for 12 hours, and the Cl can only be guaranteed to be less than 500ppm; for example, the invention with the publication number CN102115214A prepares a D50 of about 5 μm cobalt carbonate, but this method adds a variety of surfactants and complexing agents, the impurities in the product are difficult to handle, and the follow-up processing cost is bound to be high; the publication number is CN102910686A In the invention, a low-temperature (0-30° C.) synthesis method is adopted , prepared cobalt carbonate with a D50 of 1.6-2.4 μm, but in this method, the interception effect of D50<1.5 μm particles is limited during micropore filtration, and the product yield is low, and it is difficult to effectively remove it by rinsing in micropores Cl ion

Images