SU697403A1 - Method of purifying spent zinc-containing nitric acid solution - Google Patents

Description

I

The invention relates to a method for the purification of spent zinc nitrate solution and can be used in the printing, radio and other industries.

A known method of purification of spent zinc on the holding solution by treating it with chemical reagents, which use soda ash, lime and marble chips. However, this method does not ensure the return of the zinc-containing solution for reuse in the technology, due to the formation of hardly soluble compounds that are exported to the disposal floor, 1.

In addition, a method for purifying zinc-containing nitric acid solution is known by electrolytically separating impurities with the return of zinc to production 2. However, this method does not indicate the negative effect of nitration on current output of zinc.

The closest to izbreta: p1yu on technical dryness and the achieved result is a method of purification of the mature zinc containing nitric acid solution, including neutralization with adherent sodium and forming a suspension of zinc hydroxide;

The disadvantage of the known method is that it does not provide a sufficiently complete degree of purification of the cyto-containing solution of nitrate ions, the content of which is 4.4 g / l, which exceeds the allowable 5th cubic concentration (0.5Og / l) and does not allow To complete the product yield more than 08%.

The aim of the invention is to improve the degree of purification of gin ions, and to increase the yield of the finished product. 3c. The goal is achieved by the fact that, before neutralization, the waste solution B is used to introduce sodium chloride and hp1c1 to the zinc glyoxide sublimation by means of a solution of sodium chloride, and p and m. To the waste solution containing nitric acid with a concentration of 76 g / l and nitric acid zinc 4O g / l (zinc), sodium chloride is added in an amount of 40 g / l. The half solution is treated with a 15% solution of sodium hydroxide to pH-9, 5 and the resulting zinc hydroxide, containing 82 g / l of nitrate ions, is crumbled with a solution of chloroxol (sodium) chlorine with a concentration of 40 g / l. According to a content analysis of citrate ions, it is 0.21 g / l and the yield of roTOF3or-o product (zinc) is 95%. This method provides an increased degree of purification of zinc-containing solutions from nitrate ions and reduces their content from a concentration of 4.4 to 0.21 g / l and also justifies an increase in the yield of the finished product from 68 to 95%. S o rm u l a i p o b r o t o i s Slyusob purification of spent zinc – solor kashche1X) nitric acid solution, which includes neutralization of the canker with 1 gatrom to form a suspension of zinc hydroxide, washing the suspension, preparing an electrolyte from the washed zinc – richhe suspension of electrolyte and isolating zinc electrolysis. Characterized in that, in order to increase the degree of purification from nitrate ions and increase the yield of the finished product, sodium chloride is introduced into the waste solution by neutralization and washing is carried out with a solution of sodium chloride. Sources of information taken into account during examination 1. Devtov N. I. et al. On the issue of cleaning zincographic effluents. Polygraph, 1975, No. 7, p. 13. 2, Applied Electrochemistry. Chemistry, L ,, 1974. 3. Karin Keen -Yu. V. et al., Кksty. Chemicals, M., Himi, 1974, p. 399 (prototype).