SU1574535A1 - Method of obtaining potassium chloride from magnesimu-containing sylvinites - Google Patents

Abstract

The invention relates to chemical technology of substances and can be used to obtain potassium chloride in the processing of sylvinites with a high content of magnesium. The method allows to create the possibility of processing while maintaining the degree of extraction and improving the quality of the commercial product. Magnesium containing sylvinite is treated with hot liquor, halite-clay sludge is separated, and potassium fluoride is added in a molar ratio of MGCL ₂ : KF = 1: 1,95- 2.0. The hot liquor, purified from magnesium, is sent to the crystallization of potassium chloride, and the mother liquor to the preparation of a solvent liquor. The magnesium fluoride precipitate is filtered off, washed and the water after washing the precipitate is sent to obtain an additional amount of potassium chloride. 1 tab.

Description

 The invention relates to chemical technology of inorganic substances and can be used to obtain potassium chloride in the processing of sylvinites with a high content of magnesium.

The purpose of the invention is to create the possibility of processing ores with a high magnesium content while maintaining the degree of extraction and improving the quality of the commercial product.

The invention is illustrated as follows. examples.

Example 1. 100 g of sylvinite composition, wt.%: KC1 20,45; NaCl 66.35; MgCl. 3.70; insoluble residue 4.5; 5.0 is dissolved at 110 ° C in 200 g of dissolving liquor of the following composition, wt%: KCl 11.25;

NaCl 20.32; H20 68.43. After dissolution, 99.50 g of halite-clay slime and 198.5 g of hot liquor are released: liquor of the following composition, wt%: KCl 1.80; NaCl 15.15, MgCl2 1.70, HgO 63.35.

7.49 g of a 55% potassium fluoride solution in a KF: MgCl2 2: 1 molecular ratio is added to the hot liquor to precipitate. The deposition process is carried out at 100 ° C, the precipitate formed in the amount of 7.78 g of composition, wt.%: NaCl 5.17; KC1 33.50; MgF2 28.41; The HgO 32.92, is separated from the hot liquor and sent for washing. Hot liquor in the amount of 190.50 g of the following composition, wt.%: KC1 22.04; NaCl 15.57; H20 62.39, cooled to.

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In this case, 24.20 g of potassium chloride of composition, wt.%, Are liberated: NaCl 2.20; KC1 91.61; HgO 6.19 and 166.3 g of the mother liquor of the following composition, wt.%: NaCl 17.52; COP 11.91; H40 70.57. The latter is directed to the dissolution of new portions of sylvinite ore.

The magnesium fluoride precipitate, after separation from the hot liquor, is washed with water (5.50 g) and filtered. Received 3,30 g of sediment of the following composition, wt.%: MgF-j. 66.97; NaCl 0.19; KS1 0.25; NgO 32.59. Wash water in the amount of 9.98 g is evaporated at 110 ° C to remove 5.60 g. The resulting suspension is cooled to 25 ° C, and an additional 2.58 g of potassium chloride of the following composition, wt.%, Is liberated: NaCl 1.25; KC1 93.30; H20 5.45 and 1.80 g of the stock solution of the composition, wt.%: NaCl 20.05; COP 11.10; HgO 68985, directed by i.a. Preparation of the solvent liquor. The recovery rate of potassium chloride is 95.5%.

Example 2. K198.50 g of hot liquor composition, wt.%: KC1 19.80; NaCl 15.15; MgCU 1.70; H20 63.35, after separating the halite-clay slurry obtained in Example 1, 7.11 g of a 55% potassium fluoride solution is added, i.e. with a ratio of KF: MgCLz - 1.95: 1.0. Precipitation is carried out at 100 ° C. A precipitate formed in the amount of 7.40 g of composition, wt.%: NaCl 5.14; KC1 33S51; MgCl2 0.03; MgFz 28.38; 32.94, removed from the hot liquor and sent for washing. Hot liquor in the amount of 190J5 g of the following composition, wt.%: NaCl 15.58; KC1 21.96; MgCl2 0.08; H20 62.38, cooled to 25 ° C, while releasing 24.20 g of potassium chloride of composition, wt.%: NaCl 2.20; KC1 91.61; HZ0 6.19, and 166.30 g of stock solution of the following composition, wt%: NaCl 17.53; COP 11.83; MgCl2 0.10; H20 70.54, which is directed to the preparation of the solvent liquor.

After separating the magnesium fluoride precipitate from the hot liquor, it is washed with 5.5 g of water and filtered. Thus, 3.15 g of washed precipitate of the composition is obtained, wt.%: NaCl 0.15; KC1 0.20; MgF2 66.67; H40 32.98 and 9975 g of washing solution of the following composition, NaCl 3.85; KC1 25.38 ME1g 0.02; 70.75, which is evaporated at 110 ° C to remove 5.60 g

. The resulting suspension is cooled to 2 ° C, and an additional 2.48 g of potassium chloride of the composition, wt.%: NaCl 2.00, KC1 92.5, H20 5.5, and 1.67 g of the mother liquor of the composition NaCl 19 are isolated, 46; KCl 10.78, MgCl2 0.12; 69.58. This solution is sent to dissolve the sylvinite ore. The recovery rate of potassium chloride is 95.1%.

Potassium fluoride is added in the form of a 55% solution in an equimolar ratio of KF: MgCl2 2.0-1.95: 1, since at ratios less than 1.95 there is an incomplete precipitation of magnesium and, therefore, incomplete purification of hot liquor from magnesium, which reduces the degree of extraction of potassium chloride from the raw material and leads to its contamination with sodium chloride.

The KF: MgCl2 ratio greater than 2.0 is also unacceptable, since it results in the appearance of sodium and potassium fluorides in the mother liquor. This reduces the quality of potassium chloride and increases the consumption of potassium fluoride reagent.

The removal of magnesium from the hot liquor is carried out at 100-110 ° C, since the cooling of the liquor leads to the co-crystallization of potassium chloride with the resulting MgF precipitate, as a result of which loss of product occurs.

The crystallization of potassium chloride from the solution is carried out by lowering the temperature of the hot liquor from 100 to 25 ° C. Premature lowering of the temperature of the solution can lead to the indicated losses. Thus, in order to avoid losses, the removal of magnesium is carried out at a temperature not lower than 100 C.

The quality of the product obtained by the proposed and known methods are presented in the table.

Thus, the proposed method allows the processing of sylvinites with a magnesium chloride content of up to 6.34%, while in the known this value is 0.55-1.00% while maintaining the recovery rate (in the known 95.90%, in the proposed 95.53%) and improving the quality of the product (in the well-known K, C1 96.04%, in the proposed 97.65%.

Claims (1)

Invention Formula . A method of producing potassium chloride from magnesium-containing sylvinites, including their leaching with hot liquor, separating halite sludge and clay slime, separating magnesium by injecting an inorganic additive, crystallizing potassium chloride, and returning the purified solution to a cycle, characterized in that increased magnesium content while preserving the degree of extraction and improvement of the quality of the marketable product, by reducing the content of impurities, as an inorganic additive, use Comforting potassium fluoride, which is introduced into hot liquor with a temperature of 100-110 ° C in a molar ratio of MgCl: KF 1: 1.95-2.00 with the formation of magnesium fluoride precipitate, washing the latter and crystallization of potassium chloride from the wash water. 90.60 3.60 0.13 5.67 91.61 2.20 6.19 97.65 2.35