SU861319A1 - Method of producing manganese nitrate tetrahydrate - Google Patents

Description

(54) METHOD FOR PRODUCING MANGANESE NITROGENIC FOUR-RESIDENTIAL

The invention relates to the production of manganese nitrate by crystallization from saturated solutions and can be used in the manufacture of chemical reagents. .

There is a known method for producing manganese tetrahydrate nitrate, where solid carbon dioxide is added to the melt manganese nitrate hexate. The latter passes into the gaseous phase and causes spontaneous crystallization. The excess heat is removed by cooling. The product obtained by the described method is manganese nitrate four water SI

The disadvantage of the method is that the product thus obtained passes over time into a hexahydine hydride.

The closest in technical essence and the achieved result to the described invention is a method of obtaining manganese four-water solution from a solution by acidifying the solution with nitric acid to 1 May. % evaporation of the solution to 68-69 wt.%

cooling and crystallization of the SZZ.

The disadvantage of this method is that manganese nitrate obtained in this case has a strong tendency to adhere and forms a dense, hard-to-separate monolithic layer. In addition, this product is not homogeneous, but is a mixture of four- and six-hydrogen hydrates.

The aim of the invention is to obtain a homogeneous chemical composition of the product.

The goal is achieved by the described method of obtaining manganese nitrate four-water solution from the solution, including acidification

15 of the solution, its evaporation and subsequent crystallization, in which the initial solution is acidified to a free nitric acid content of 1.52, 0 wt%, the evaporation is carried out to a concentration of 70-71 wt% of the solution, and the manganese seed tetrahydrate nitrate and the resulting suspension is subjected to centrifugation.

25 The amount of injected seed is 0.8-0.1% by mass of the crystallized corn, and centrifugation is carried out at a temperature of 30-35 ° C.

Introduction to the evaporated solution of 30 nitric acid is less than 1.5%

not enough, since the phenomenon of thermolysis, which is manifested in the formation of manganese oxides, is not eliminated. Introduction to the solution of a larger amount of nitric acid, more than 2.0 wt.%, Does not increase the quality of the evaporated solution. The amount of seed introduced is optimal for obtaining crystals of the required size of 300500 microns.

A smaller amount of seed does not provide a sufficient rate of crystallization, and more leads to the formation of small crystals, which are difficult to separate from the mother liquor. The proposed concentrations and temperature correspond to the maximum yield of manganese nitrate four-water, which confirms the chemical analysis of the crystals. At a centrifugation temperature below 30-35 ° C, the final product turns into a six-water form.

The essence of the invention is as follows: the initial manganese nitric acid solution is acidified to a content of free nitric acid of 1.52, 0 wt.% And evaporated to a concentration of 70-71.4 wt.%. Then it is cooled in a heat exchanger to a temperature of 21-25 ° C and a seed made of manganese nitrate four-water crystals is introduced. The latter causes spontaneous crystallization and an increase in the temperature of the solution due to the addition of heat. After it is set at a level of 32-35 seconds, crystallization is considered complete and the suspension is separated in a centrifuge with heating at a temperature of 30-35 ° C. The resulting solid phase is manganese nitrate tetrahydrate. The chemical analysis of the melt shows that the manganese nitrate content in it is from 70 to 71.5% by mass.

Example. The solution of manganese nitric acid, acidified to the content of free nitric acid of 1, 5 wt.%, With a concentration of .30 wt.%, Is evaporated to a concentration of 70 wt.%. The amount of the original solution is 2.50 kg; the amount of the final solution is 1.07 kg. Then the solution is cooled to a temperature of 23 ° C. After that, the seed of manganese nitrate four-water crystals in the amount of 0.01 g was added to it. The beginning of crystallization and temperature increase were noted. After the termination of temperature growth at the level of the suspension, it is subjected to separation in a heating centrifuge at. Centrifugation time 10 min. The amount of solid phase 0.52 kg; liquid - 0.50 kg. The resulting product is white crystals, according to chemical analysis, corresponding to the formula Mn (NO ,,) a-4H, iO.

PRI mme R 2. The acidified solution of manganese nitric acid, acidified to the content of free nitric acid at 2 May, evaporated to a concentration of 70.03% w. 03 kg. Then the solution is cooled to a temperature of 25 s. After that, 0.01 g of manganese nitrate acid sulfate crystals are seeded into it in an amount of 0.01 g. The onset of crystallization and an increase in temperature are noted. After the end of the temperature rise at the level of the suspension, it is subjected to separation in a centrifuge with heating at a temperature. Centrifugation time 10 min. The amount of solid phase of 0.48 kg, liquid - 0.50 kg. The obtained product is white crystals according to chemical analysis that correspond to the formula Ml (N0.5) a4H20.

Froze Acidified to a content of free nitric acid of 2% by weight of manganese; nitrate acid concentration of 30 May.% evaporated to a concentration of 70.10 May. % The amount of the original solution 2.49 kg, the number of the final - 1.06 kg. Then the solution is cooled to 21 ° C. After this, manganese crystals of nitric acid were added to it in the amount of 0.012 g. The onset of crystallization and an increase in temperature were noted. After the end of the temperature rise at 34 ° C, the suspension is subjected to separation in a heating centrifuge at 31 ° C. Centrifugation time 10 min. The amount of solid phase 0.53 kg, liquid - 0.49 kg. The resulting product is white crystals, according to the chemical analysis data corresponding to the formula Mn (NO) - 4H20.

The product chosen by this method is free-flowing, poorly caking and easy to work, storage and transportation of which can be carried out in a polyethylene container. The economic effect from the implementation of the invention will be about 104 thousand rubles. per year with the planned production in 1980, 1100 tons / year due to increased labor productivity, lower energy costs and increased product yield.

Claims (2)

1. A method for producing manganese tetrahydrate nitrate from solution, including acidifying the solution, evaporating it, and subsequent crystallization, characterized in that, in order to obtain a homogeneous chemical composition of the product, the original solution is acidified to 1.5-2.0 free acid May.%, uparku lead to a solution concentration of 70-71% May.% | Manganized nitrate four-water nitride is introduced into one stripped off and cooled solution, and the resulting suspension is subjected to centrifugation at a temperature of 30-35 ° C. . 2. A method according to Claim 1, characterized in that the amount of the injected seed manganese nitrate four-water manganese is O, 8-1, O May from the mass to be crystallized. Sources of information taken into account in the examination 1. US patent number 2017980, CL.23-102, published.1933. , 2. USSR author's certificate 251560, cl. From 01 G 45/08, published 1970 (prototype).