SU964024A1 - Method for washing diaphragm of chlorine electrolyzer - Google Patents

Description

worked by a reducer to destroy active chlorine.

Saturation of the wash liquid with carbon dioxide is carried out by bubbling of acid gas through it in the anode space of the electrolyzer or by introducing solid carbon dioxide into the anode space. Saturation of the washing liquid with carbon dioxide can also be carried out before it is supplied to the electrolyzer in the apparatus under pressure with maximum displacement.

For the economy of carbon dioxide, washing can be carried out in two stages - first with water or brine, lax hard salts and soda, and then with a solution of carbon dioxide. To prepare the carbon dioxide solution, both brine or water are used, both purified and unpurified from hardness salts and soda.

Brine or water is purified from hardness salts known, for example, soda-alkali. M, method. In using this method to clean the brine, the latter is treated with hydrochloric acid to pH 3-4 to destroy the soda, and then neutralized by adding alkali to a pH of 5-7.

PRI me R 1. Flush the diaphragm

Trolizers off after 4 months of operation at a current density of 1500 A / m and the composition of the feed brine, g / l: 310 NaCl; 0.05 NaOH; 0.4 NasCOg n 5 mg / l Ca ion.

After the current is turned off and the catholyte is drained from the cathode space of the electrolyzer, the diaphragms are washed by supplying the washing liquid to the anode space and withdrawing it from the cathode space of the electrolyzer.

Diaphragm No. 1 8 hours with distilled water saturated with carbon dioxide while bubbling carbon dioxide through the washing liquid in the anode space of the electrolyzer, diaphragm No. 2 - 18 hours with purified brine devoid of salts of salt and soda, diaphragm No. 3 - 8h

. Cleaned from hardness and soda salts with a brine saturated with carbon dioxide.

The diaphragm No. 4 is washed according to a known method-prototic with acidified hydrochloric acid to brine to pH 2 at such a supply that the pH value of the liquid flowing out of the cathode space by washing is equal to m 6.

The performance indicators of chlorine electrolytes, hectare gels under the same operating conditions as before the washing of the diaphragms, 3 months after the RINSING are shown in Table. one.

Example 2

The asbestos diaphragms of three electrolyzers are turned off, turned off after 4 months of operation at a current density of 1500 A /. M and using the brine of the composition indicated in example 1.

Diaphragm No. 1 is washed for 10 hours with tap water, saturated with carbon dioxide, diaphragm No. 2 - 9h with brine, 50 mg / l ioia and 0.2 g / l of soda and saturated carbon dioxide, diaphragm No. 3 - 4h with brine, no electroscope number. .chizs1) a

it burns hardness and soda salts, and then, for 6 h, a nitrating brine saturated with carbon dioxide.

 The performance of chlorine electrolyzers under the same operating conditions as before the washing of the diaphragms, three months after the washing, is given in Table. 2

Washing the diaphragm according to the invention provides a longer service life and requires less time for its implementation.

Claims (3)

1. Fainshtein S. Ya. Production of chlorine. diaphragm electrolysis method - “Chem. M., 1966, p. 185. 2. Collection of instructions for the installation and operation of the electrolyzer BGK-75, KB 101284, NE, 1973, p. 72-79. 3. US Patent No. 3467586, cl. 204-98, 1976 (prototype).