SU1555281A1 - Method of obtaining sodium chloride from solutions of processing polymineral potassium ores - Google Patents

Abstract

The invention relates to the technology of the integrated use of solutions for the processing of polymineral potash ores, can be used to produce table salt and helps to reduce energy costs while maintaining the quality of the product. According to the method, the processing solutions of polymineral potash ores are evaporated in a multi-body vacuum evaporation plants to a concentration of magnesium in the solution of 4.0-4.5% with the separation of the product at 75-85 ° C. The evaporation of the solution starts at 115-140 ° C and is carried out until reaching the concentration of magnesium in the solution, determined from the relationship C% * 98 7.9-0.0365T, where C% is the concentration of magnesium in the solution, T is the evaporation temperature, ° C . The method contributes to an increase in the number of installation cases up to 4-6 and a significant reduction in energy costs while maintaining the quality of the salt produced. 3 tab.

Description

The invention relates to the technology of the complex use of solutions for the processing of polymineral potash ores and can be used to produce table salt.

The purpose of the invention is to reduce energy costs while maintaining the quality of the product.

Example 1. 10 kg of a solution for processing polymineral potash ores of the following composition, wt.%: K4 3.56; , 56; Na + 5.03; C1 15.02; SO 4.65; H20 69.18, evaporated at 140 ° C to 90.2% of the original mass. Get one stripped off solution following

its composition, wt.%: 3,90; Mg2 + 2.80; Na 6.01; Cl 17.27V SO + 5.07; HjO 64.93, and an unwashed precipitate of salt composition, wt.%: To 0,58; 0.40; Na + 35.52; Cl 55.91; S04 0.85; HgO 6.71. After that, the solution is continued to be evaporated at 123, 106, 72, 55, and 89 ° C to a final depth of evaporation equal to 65.2% of the initial mass.

Get 5,495 kg one stripped off solution of the following composition, wt.%: K + 6.07; Mga + 4.51; NaV 3.04; C G 17.28; SO 8.22; NaO 61.07 and 1.078 kg of unwashed table salt, composition

sl to

po

the second after washing the following, May.%: K4 0.17; MR 0.07; Na 36.85; SG 57.14; ,13; HgO 5.62.

The useful temperature difference between the beginning and the end of the evaporation makes it possible to perform the evaporation in six steps, the useful temperature difference across the hulls minus the temperature depression. Steam consumption for 1 kg of salt 1.02 kg.

Example 2. 10 kg of the solution processing of polymineral potash ores from example 1 is evaporated at 130 ° C to 88.0% of the original mass. One stripped off solution of the following composition is obtained, wt.%: K + 4.07; Mg2 + 3.02; Na + 5.48; C G 17.18; SoЈ 5.06; HgO 65,21, and unwashed precipitate of salt composition, wt.%: K 0,88; Mga + 0.61; , 85; SG 52.37; SO 1.21; 12.08. After that, the solution continues to be evaporated at 111, 92, 55 and 75 C to 66.5% of the original mass. Get 5,638 kg one stripped off solution of the following composition, wt.%:, 58; , 23; Na4 2.89; cG 17.26; 7.46; 61,58 and 1,012k of unwashed table salt composition, wt.%: 1.70; 0.76; Na4 32.81; C1 53.18; S0l 1.60; 9.95.

The useful temperature difference between the beginning and the end of evaporation allows the solution to be evaporated in five steps, the useful temperature difference across the hulls minus the temperature depression of 12 ° C. Steam consumption for the production of 1 kg of salt 1.11 kg.

Example 3. 10 kg of a solution for processing polymineral potash ores from example 1 is evaporated at 120 ° C to 76.6% of the initial mass. Get one stripped off solution of the following composition, wt.%: K + 4.91: Mg243.51; Na 4.80; Cl 17.42; soj 6.36; H20 62.99, and unwashed precipitate of salt composition, wt.%: K 0.90; Mg2 + 0.64; Na4 33.44; SG 53.53; SO 1.24; H, 10.14. After this, the solution continues to be evaporated at 98, 55 and 78 C to 67.5% of the initial mass. 5.751 kg of one stripped off solution of the following composition is obtained, wt.%: K 5.9 Mg 4.36; Na + 2.89; Cl 16.98; SO 7.60; NaO 62.20, and 1.084 kg of unwashed table salt composition, wt.%: K 1.70; MgwO, 74f Na4 32.64; Cl 52.83; SOl 1.64; HgO 9.63.

0

five

0

The useful temperature difference between the beginning and the end of evaporation makes it possible to evaporate the brine in four steps, the useful temperature difference across the hulls minus the temperature depression is 15 ° C. Steam consumption for producing I kg of salt 1.23 kg.

The evaporation temperature in the proposed method is increased by adjusting the concentration of magnesium in the first high-temperature enclosures, respectively, with the dependence C67.9-0.0365 t. In order to preserve the total depth of evaporation in a multi-unit installation, providing an evaporated solution with a magnesium concentration of 4.0–4.5%, it is necessary to increase the number of shells. This makes it possible to obtain pure sodium chloride and reduce the energy costs of evaporation of the solution.

With increasing temperature of evaporation in the first building (more than 140 ° C), as can be seen from the table. 1, the concentration of magnesium in the solution exceeds the limiting concentration at which the crystallization of langbeinite, contaminating sodium chloride, begins. Reducing the temperature (less than 115 ° C) does not allow using four (and more) case-type vacuum-evaporation plants for evaporation due to the low (less than 7.0 ° C) useful temperature difference, which leads to a high consumption of heating steam for sodium chloride (Table 2).

An increase in the concentration up to about 7.9–0.0365 t leads to the crystallization of langbeinite and contamination of table salt. The lower limit of the evaporation (C) in the high-temperature housing depends on the number of the buildings (p) and the initial one (C, the concentration of magnesium in the solution and is determined by the equation

Sn

CHCX +

(4.0-4.5) - Sys p

A decrease in the depth of the evaporation below the specified limit does not provide an evaporated solution with a magnesium concentration of 4.0-4.5%

The proposed method allows, by increasing the temperature in the first housing of a multi-unit vacuum evaporation unit, and evaporating the solution to the maximum concentration of magnesium,

in which the impurities of langbeinite still do not crystallize, increase the number of installation cases to 4-6 (Table 3) and significantly reduce energy costs.

Claims (1)

Invention Formula The method of obtaining sodium chloride from solutions of processing of polymineral potash ores, including their evaporation in multi-body vacuum evaporation plants to a concentration of magnesium in solution 4.0–4.5% with separation of the product at 75–85 ° C, about t being different in that, in order to reduce energy costs while maintaining the quality of the product, evaporation of the solution is started at 15–140 ° C and lead it to achieve a concentration of magnesium in the solution, determined from the dependence of C% 7.9-0.0365 t, where C% is the concentration of magnesium in the solution; t - temperature steaming, C. Continuation of table 1 table 2