Preparation method of high-purity superfine cobalt oxalate powder

Abstract

The invention provides a preparation method of high-purity superfine cobalt oxalate powder, which comprises the following steps: adding a certain amount of additive into a cobalt salt solution with a certain concentration, adding a certain amount of ammonia water into an ammonium oxalate solution with a certain concentration, and adding the two solutions into a reaction kettle to react according to a certain mole ratio in a parallel-flow uniform speed spray mode while controlling the reaction temperature at 15-55 DEG C, the pH value of the reaction solution at 6-7 and the stirring rate at 10-100 rpm / minute; and after finishing feeding, aging, washing, carrying out solid-liquid separation, and drying to finally obtain the high-purity superfine cobalt oxalate powder body. The cobalt oxalate powder prepared by the preparation method has the advantages of fewer impurities, high purity and high flowability, the average particle size is 0.5-1.5 micrometers, the particle size distribution is uniform, and the shape is subsphaeroidal. The preparation method has the advantages of simple and controllable technique, high production efficiency and stable product quality, and is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to the field of metallurgy and chemical industry, in particular to a method for preparing cobalt oxalate, and more particularly to a method for preparing high-purity ultrafine cobalt oxalate powder. Background technique [0002] Cobalt oxalate is usually used as an important raw material for cobalt powder and its oxides, and is also used in cemented carbide, lithium batteries, catalysts, and electromagnetic materials. The purity, shape and particle size of cobalt oxalate determine the quality and particle size of cobalt powder and its oxides, and further affect its performance. [0003] At present, the technology for producing cobalt oxalate mainly includes two forms: solid phase reaction, solid-liquid phase reaction and liquid phase reaction. The solid phase reaction generally uses the solid of cobalt salt and oxalate as raw materials to prepare cobalt oxalate. Because the reaction process needs to introduce a large amount of...

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Problems solved by technology

[0003] At present, the technology for producing cobalt oxalate mainly includes two forms: solid phase reaction, solid-liquid phase reaction and liquid phase reaction. The solid phase reaction generally uses the solid of cobalt salt and oxalate as raw materials to prepare cobalt oxalate. Because the reaction process needs to introduce a large amount of Organic grinding aids, and the reaction occurs at the interface of two solid phases, the reaction speed is slow, the residual impurities are many, the process is cumbersome, the technical and economic benefits are poor, and it is not suitable for large-scale production; the solid-liquid phase reaction generally uses cobalt carbonate powder Reacting with oxalic acid solution to prepare cobalt oxalate, this method needs to prepare cobalt carbonate powder first, the process is long, and the cost is high, and it is not suitable for large-scale production; liquid phase reaction is the most commonly used method at present, and it uses soluble cobalt Salt and ammonium oxalate are prepared into a raw material solution, and then reacted in a liquid-liquid mixing manner, which has the advantages of simple process, fast reaction, low cost, and suitable for large-scale industrial production. However, in the process of liquid-liquid mixing reaction, it is very difficult It is easy to cause the phenomenon that the concentration of the local precipitant is too high and the reaction is too violent, resulting in too fast growth of particles, increasing the chance of agglomeration between particles, and easily forming a phenomenon of encapsulation between crystal nuclei, which eventually leads to more impurities in the product. large diameter and uneven particle size distribution; in addition, the cobalt oxalate produced by the liquid phase reaction is carried out in an acidic environment, and the obtained cobalt oxalate is generally β-CoC 2 o 4 2H 2 O, the shape is rod-like, the cobalt powder produced by the reduction of cobalt oxalate, due to the inheritance of the shape, the resulting product is generally dendritic, which limits the use of cobalt powder to a certain extent

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