SU1219526A1 - Method of producing potassium dichromate - Google Patents

Description

one

This invention relates to the chemical technology of chromium compounds, in particular to the preparation of potassium dichromate.

The purpose of the invention is to reduce the content of chloride impurities in the product and the water consumption.

Example 1. Take 100 g of a solution containing, in wt.%: Sodium chloride 18.2; potassium dichromate 0.9 sodium chromate 13.4; sodium bichromate 1.5; water 66.0; it is heated to 78 ° e and 17.7% by weight of potassium chloride are introduced with vigorous stirring. After 1.5 h, the sodium chloride is separated. The mother liquor, the oedinum, was added to 31.1 wt.% Sodium bichromate and mixed vigorously. At the end of the exchange decomposition reaction, after 1.5 hours, the potassium bichromate is separated and dried, and the solution is returned to the stage of dissolution of potassium chloride.

Example 2. The conditions for carrying out the method are similar to those in Example 1, but the solution contains, in wt%: sodium chloride 17.8; potassium dichromate 0.8, sodium chromate 13.7; sodium bichromate 1.7; water 66.0. The solution is heated to 75 ° C and after separation: the sodium chloride is cooled to 25 ° C.

The content of the main substance in the product,%

The content of h.poridov in the product,%

98.04 99.13 99.80 99.62

Compiled by L. Titov Editor I. Derbak Tehred L, Serdyukova Proofreader A. Zimokosov

Order 1225/30. Circulation 450 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d, 4/5

Filial PPP Patent, Uzhgorod, st. Project, 4

262

Example 3. The conditions for carrying out the process are similar to those in Example 1, but the solution contains, in wt%: sodium chloride 17.1 j, potassium dichromate 0.8; sodium chromate 14.0; sodium bichromate 1.9; water 66.2. The solution is heated to 77 ° C and, after separation, the sodium chloride is cooled to 26 ° C.

Analysis of the obtained {about potassium dichromate shows that the content of the main substance in it is 99.1-99.8%.

Comparative experimental data obtained by the known and proposed method are presented in the table.

It follows from the table that the content of chloride impurities decreases by a factor of 2J3-9.8 in comparison with the known method, and the water consumption decreases by.

When the concentrations of these salts in the potassium chloride solution and the temperature are outside the temperature, either co-crystallization of potassium and sodium dichromates occurs, or incomplete precipitation of the resulting salt occurs, resulting in a change in the composition of the working solution and the cycle is not closed.

The number of BUT per 1000 kg of an aqueous solution, kg

724.00 660.00 660.00 662.00

Claims (1)

METHOD FOR PREPARING POTASSIUM Dichromate, including the interaction of solutions of sodium dichromate and potassium chloride, separation of the precipitate of potassium dichromate and its drying, characterized in that, in order to reduce the content of chloride impurities in the product and water consumption, a potassium chloride solution prepared by dissolving using 75-78 ° C solid potassium chloride in a solution containing, £: Sodium Chloride Potassium Bichromate Sodium Chromate Sodium Bichromate Water 17.0-18.2 0.8 -0.9 13.4-14.1 0.9-1.9 Rest