Ammonia circulative preparation method for cobaltous oxalate

Abstract

The invention relates to an ammonia circulative preparation method for cobaltous oxalate. In the current commonest liquid phase precipitation method, because ammonium salt is introduced in the reaction process and the amount of oxalic acid is excessive during the reaction, impurities like ammonia nitrogen and oxalic acid root in synthesized waste water are required for processing. According to the invention, cobalt liquid is taken as a raw material, an oxalic acid solution is used for absorbing ammonia gas to prepare an ammonium oxalate solution which can be taken as an auxiliary material, cobalt liquid and the ammonium oxalate solution are added in a reaction vessel for synthesizing to obtain cobaltous oxalate pulp, the cobaltous oxalate pulp is filtered and washed, and dried to obtain the cobaltous oxalate product; simultaneously, waste water after filtering and washing is carried out pH regulation, ammonia molecule is separated from waste water by using an air stripping method, the oxalic acid solution is absorbed to be the ammonium oxalate solution for realizing the ammonia circulative utilization. The preparation method of the invention has the advantages that ammonia circulative utilization is realized, the waste water treatment avoids the introduction of ammonium salt and ammonia nitrogen, the production cost is reduced and the circular economy is realized.

Description

technical field [0001] The invention relates to the preparation of cobalt acid, in particular to a method for preparing cobalt oxalate through ammonia circulation. Background technique [0002] Cobalt oxalate is usually used as an important raw material for the production of cobalt powder and its oxides, and recent developments show that cobalt oxalate is also widely used as a functional material with excellent performance in many other fields. For example, some manufacturers in the field of lithium batteries are gradually promoting the use of cobalt oxalate powder as the negative electrode raw material. In the field of catalysts, cobalt oxalate powder is also being used, and there is also the development and utilization of cobalt oxalate powder to prepare new electromagnetic materials. Technology, etc. wait. [0003] The preparation methods of cobalt oxalate powder mainly include solid phase reaction method, solid-liquid phase reaction method and liquid phase reaction meth...

AI Technical Summary

Problems solved by technology

The solid-phase reaction method adopts the solid of cobalt salt and oxalate as raw materials, and through grinding, cobalt oxalate is synthesized in a solid-phase reaction mode; its disadvantage is that a large amount of organic matter must be introduced during the solid-phase reaction, and the solid-phase reaction is between two The interface of a solid phase occurs, the uniformity is poor, the reaction speed is too slow at room temperature, and the economic benefit is poor.

The solid-liquid phase reaction method (such as patent document CN101780545A) uses cobalt carbonate powder and oxalic acid solution to prepare cobalt oxalate, but this method needs to prepare cobalt carbonate powder first, and the process is long and the cost is high

The liquid phase precipitation method is the most common method at present. It usually uses soluble cobalt salt and ammonium oxalate to prepare the raw material liquid, and then reacts in a liquid-liquid mixing manner. It has the advantages of simple process, fast reaction and low cost; however, Due to the introduction of ammonium salts in the reaction process and excessive oxalic acid during the reaction, the synthetic waste water contains impurities such as ammonia nitrogen and oxalate that need to be treated

For the treatment of this wastewater, some manufacturers use electrodialysis and evaporation crystallization, which consumes a lot of energy, costs a lot, and is difficult to maintain.

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