RU1787773C - Method for preparing wood antiseptic - Google Patents

Abstract

The method relates to the production of means for protecting wood products from decay. A wood antiseptic is obtained by preparing a mixture containing water, copper sulphate, boric acid, exolite and a spent solution of chromium electrolysis baths, with a spent solution content of 15-20 wt.% In the resulting mixture. The concentration of chromic anhydride in the spent solution of chromium electrolysis baths is 200-300 g / l, 2 tables.

Description

... H.H.

The proposed method relates to the production of means for protecting wood products from decay.

The closest to the invention in technical essence and the achieved result is a method of producing a wood antiseptic by mixing at a temperature of 35-40 ° C with water copper sulfate, boric acid, epsomite and sodium dichromate (potassium chromate) in a ratio of 0.65: 0 , 10: 0.03: 0.18: 0.04 with acidification of the medium with sulfuric acid ..

The disadvantage of this method is that qualified reagents are used to prepare this agent, which complicates and increases the cost of the process.

The aim of the invention is to simplify the process while maintaining the quality of wood antiseptics.

This goal is achieved by the fact that in the method for producing a wood antiseptic according to the Invention, water, copper sulfate, boric acid, epsomite are mixed with

spent solution of electrolysis baths of chromium plating, in which the concentration is. the amount of chromic anhydride is 200-300 g / l, the proportion of the spent solution in the mixture being 15-20%.

The selected range of chromium concentrations in the spent solution of electrolysis baths is explained by the fact that this solution is prepared by mixing in a certain ratio of chromic anhydride with sulfuric acid, and at an anhydride concentration of less than 200 g / l, the amount of acid is insufficient to acidify the antiseptic to the required pH 1.2- 2.1, which necessitates the addition of sulfuric acid to the antiseptic, i.e. complicates the process. When the concentration of chromic anhydride in the spent solution exceeds 300 g / l, salts of chromic acid are formed containing iron, copper, zinc and aluminum ions released into the solution during electrolysis. These salts are insoluble in antiseptics, which complicates the process due to the need for XI 00

VI VI VI

with

days of an additional stage of filtration and loss of raw materials (chromium) with an insoluble residue. The selected fraction of the spent solution in the antiseptic mixture is explained therein. that at a concentration in the mixture of less than 15%, the pH of the medium is more than 2.1, which reduces the antiseptic properties of the finished product, and at a concentration of more than 20%, the product is oversaturated with less color, i.e. the quality of the product (6ke is deteriorating. Rome. 5359 kg of water is mixed at a temperature of 35-40 ° C with 1800 kg of the spent solution of electrolysis baths of chromium plating (concentration of chromic anhydride is 250 g / l). 287 kg of boric acid, 965 mg of copper sulfate, 1721 kg of epsomite, 10,232 kg of wood preservative containing oxides are obtained: chromium 6-4.4%, copper 3.0%, boron 1.6%, magnesium 2.7%, sulfates 10, 1% prH 2 .:,. notes; y; -n; .. /

The quality of the product obtained by the prototype and the proposed method is the same and meets the requirements for it, both in color and in resistance to decay, as can be seen from the table.

1,1; -; V; i -; -,: - --o 3r q-fC-t.; . ;

Loss of solid phase chromium with an increase in the concentration of chromic anhydride in the spent solution over 300 g / l increases sharply. This reduces the efficiency of the use of the solution and requires additional costs for the utilization of chromium in the solid phase.

As can be seen from the tables, the almost full use of chromium without the addition of sulfuric acid in the process of obtaining the antiseptic gtri the required product quality is achieved in the range of concentrations of chromic anhydride in the spent solution of chromization electrolysis baths of 200-300 g / l and the proportion of this solution in the mixture of 15-20%.

Compared with the prototype, the processes for obtaining a wood antiseptic are simplified (reducing the number of components to be mixed and mixing operations by eliminating the dosage of sulfuric acid, using sodium bichromate instead of a flaming highly toxic substance with an oxidizing ability equivalent to chromium trioxide) while maintaining the required quality of the antiseptic (certain concentration of oxidizing agent - trioxide

chromium).

Using the proposed method for the preparation of wood antiseptics will also allow to utilize the waste of metal chromium plating

products using the chromium present in them instead of its qualified compounds.

25

Formula a

Claims (2)

1. A method of producing a wood antiseptic, comprising preparing a mixture containing 1 water, copper sulfate, boric acid, epsomite, a chromium-containing component, characterized in that, in order to simplify the process while maintaining the quality of the wood antiseptic, a spent solution of electrolysis baths is used as the chromium-containing component chromium plating in an amount of 15-20 wt.% of the mass of the resulting mixture. 2. The method according to claim 1. characterized in that the concentration of chromic anhydride in the spent solution of the electrolysis baths of chromium plating is 200-300 g / l. Table 1  Dol waste solution in a mixture of 17% table 2