Method for producing high-purity manganese nitrate

Abstract

The invention discloses a method for producing high-purity manganese nitrate. The method comprises the following steps: step 1, carrying out a synthetic reaction in a quartz glass device by taking industrial nitric acid and electrolytic manganese metal as raw materials; step 2, adding a proper amount of an amino-carboxyl chelating agent into the synthetic reaction solution, continuously stirring,and then standing and precipitating; step 3, filtering the solution, concentrating, cooling and crystallizing; and step 4, after the crystallization is completed, carrying out dehydration treatment toobtain primary crystals, and carrying out recrystallization treatment on the primary crystals to obtain the product. Metal ion impurities in the product are removed by using the amino-carboxyl chelating agent; the content of metal impurities in the manganese nitrate product meets the high-standard requirements of customers, and meanwhile, the influence of the aminocarboxylic chelating agent serving as an impurity can be completely ignored due to the extremely small addition amount of the amino-carboxyl chelating agent, so that the technical defect that high-purity manganese nitrate cannot beproduced at low cost in the prior art is overcome.

Description

technical field [0001] The invention relates to the technical field of manganese nitrate production, in particular to a method for producing high-purity manganese nitrate. Background technique [0002] Manganese nitrate is an inorganic compound, soluble in water and alcohol, heated to precipitate manganese dioxide and release nitrogen oxide gas, cooling and crystallization to form manganese nitrate hexahydrate crystals, manganese nitrate hexahydrate is a light rose needle-shaped diamond crystal, at 160-200 ° C When it decomposes to form manganese dioxide, it is easy to deliquescence. The method for industrially producing manganese nitrate comprises: using manganese ore as raw material, reacting with nitric acid, purifying and removing impurities, and concentrating and crystallizing to prepare, or reacting manganese carbonate / manganese hydroxide with nitric acid, or using metal manganese as raw material, and Nitric acid is produced by synthetic reaction, among which, the use...

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Problems solved by technology

[0003] There are many uses of manganese nitrate. When it is used as a micro-analysis reagent and oxidant, or used to prepare electronic components, the purity of manganese nitrate is very high, and the purity must be at least 99.8%, and impurities such as metal ions must be in the Within a certain range (specifically can refer to specification table 1), obtain according to inventor's understanding and detection to the high-purity manganese nitrate product on the existing market for many years, the high-purity manganese nitrate impurity content of existing industrialized production is on the high side (mainly Metal ion impurities), the impurity index is not good, and it is increasingly unable to meet the high standard requirements of customers

[0004] Chinese patent CN103435103B discloses a kind of high-purity manganese nitrate and preparation method thereof, and it adopts manganese sulfide-nitric acid process route, has obtained the high-purity manganese nitrate product of low heavy metal content, although its metal ion content has reached the high-purity manganese nitrate product requirements, but due to the introduction of a large number of new substances sulfide and sulfate, the index of sulfate and sulfide content in the product will be obviously high, and sulfate is one of the main detection indicators of high-purity manganese nitrate, although the patent does not Its index is listed, but, for those skilled in the art, as common sense, introduce sulfide and vitriol in a large amount, will certainly make this index exceed the standard in the manganese nitrate product (high-purity manganese nitrate sulfate content≤0.02wt %), therefore, although this method has solved the problem that existing product metal ion impurity content is high, also brought new impurity problem (sulphate exceeds standard), and it is not preferred solution

However, the content of metal ions in the solution is trace. This method uses hydroxide ions to remove metal ions. Metal hydroxides are slightly soluble in water, so most of the metal hydroxides cannot be removed. The effect of removing impurities is not as good as No, although in the data shown in Table 1 of the specification, the metal ion content of the product is extremely low and has reached the high-purity standard, but according to the judgment of those skilled in the art, when ammonium carbonate is used to remove metal ions, it will also consume A large amount of manganese ions obviously consume a lot to the product, and the yield is affected. Therefore, in this method, a large amount of ammonium carbonate and aqueous ammonia need to be added, and the use of ammonium carbonate will also produce a large amount of ammonia. When it is directly applied to industrial production, it consumes a lot of chemicals and generates a lot of waste gas, which is not conducive to low-cost production of enterprises. Therefore, it is not suitable for industrial applications

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