SU1623954A1 - Process for producing potassium chloride - Google Patents

Abstract

The invention relates to the technology of mineral fertilizers and can be used to obtain potassium chloride from sylvinite ores containing calcium and magnesium chlorides and insoluble compounds. The purpose of the invention is to increase the recovery rate of potassium chloride. The method includes a two-stage leaching of crushed sylvinite by heating with a circulating mother liquor to obtain a suspension at 110-115 ° C of a saturated solution of potassium and sodium chloride containing sodium sulphate and soda in an amount of 0.3-3.86 and 0.4-2, 26 ma.ch. respectively, separation of gmlit and clay slime, crystallization and separation of potassium chloride from the mat solution, drying in an f.apa-bath drier. The yield of potassium chloride is increased by 4-10%, depending on the content of magnesium and calcium chlorides in the ore. 1 part f-you, 2 tab. C Ј (L

Description

The invention relates to the technology of mineral fertilizers and can be used to obtain potassium chloride from sylvinite ores containing calcium and magnesium chlorides and insoluble compounds.

The purpose of the invention is to increase the recovery rate of potassium chloride.

The preparation of potassium chloride is carried out as follows.

The sylvinite-ore ore is fed to the first stage of dissolution into the solvent, to which a solution saturated with potassium and sodium chlorides is fed, with the addition of sodium sulfate and soda to it in order to precipitate calcium and magnesium. Temperature of dissolving liquor P (L150С.

Next, the solid phase — sodium chloride g with an admixture of potassium chloride — is directed to the excess alkilinity of the guilvine in the second solvent. The first solvent works on the principle of the second motor - counterflow. The dehydration and washing of the halite dump with water or brine from the sludge storage is carried out on vacuum filters. The washed dump - sodium chloride with a minor admixture of potassium chloride is discarded.

The saturated solution flows by gravity into the system of settling tanks, where the solution is clarified from clay particles with magnesium carbonate and gypsum. The thickened clay slimes are washed and removed from the process.

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The clarified saturated solution is fed to a vacuum crystallization unit, where it is cooled from 92-98 to 25-35 ° C due to the self-evaporation of the solution under vacuum. The resulting potassium chloride slurry is thickened in settling tanks. The thickened slurry is filtered in centrifuges. The moisture content of potassium chloride concentrate is 4-6%. The filtrate from the centrifuge is returned to the sedimentation tanks for additional clarification. The clarified solution is sent to the first and second solvents in a weight ratio of I: 2. The cadi chloride is dried in a tumble dryer.

With the introduction of the sodium chloride sulphate and soda sodium chloride saturated with potassium and sodium chloride saturated with potassium and sodium chlorides, sodium chloride calcium sulfate hemihydrate and basic magnesium carbonate are formed in a saturated solution before the halite sludge and clay slurry are dissolved. The resulting water-insoluble compounds crystallize on the gypsum and salt components of the clay slurry, represented by carbonates, sulphates and silicate impurities and hydrous sludge, are captured by particles of insoluble residue, which are suspended in the leached ore. Simultaneously with the release of calcium and magnesium ions from a solution, the aggregation of clay-salt slurry particles occurs, which contributes to a more intense illumination of the solution.

When separating the resulting clay-salt slurry, an enlarged particle size distribution, the amount of impregnating mother liquor decreases, the loss of potassium chloride with the impregnating mother liquor decreases and its extraction into the finished product increases.

Feeding the solution containing sodium sulfate and soda to dissolve the vinite ore forces before separating the salt slurry reduces the supersaturation of the CaS04 solution and compounds, separates the clay-salt slurry and the products of the proposed reagents without one step, washing the precipitates, and therefore exclude product losses due to

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washing with KC1 and water-insoluble calcium and magnesium compounds,

The temperature of the solution containing sodium sulfate and soda, PO-115 ° C, should not be lower than the temperature of the solution in the solvent, since if the temperature in it decreases due to the introduction of the cooled solution with reagents, some of the potassium chloride remains in the ore and leaves consequently, the degree of recovery of KCl in the solution and then in the product decreases. A further increase in temperature above 115 ° C is impractical.

The solution with pea ents (,) must be saturated with potassium and sodium chlorides or close to saturation, since the introduction of an unsaturated solution into the process will result in potassium loss either due to the solution solution (with KC1 unsaturation) or with salt sludge (at non-saturation according to Nad, but concentrated (bath according to KC1).

Examples are 1. 100 mah. Silvinit ore of the following composition, wt.%: KC1 24.95; NaCl 67.9; NRS 0.27; CaClfc 0.28; H About 6.2; HgO 0.40 is crushed and subjected to two tadium leaching by heating with circulating mother liquor to form a suspension.

The dissolution is carried out at MO G, 230 ma.ch. dissolving liquor of the following composition, wt.%: KC1 9.8; NaCl 14.3; MgCJ2 0.95; .CaC12 0.90; H, 0 74.05. i

In the suspension obtained: a saturated solution of potassium and sodium chloride is introduced at 110-115 ° C, containing 0.3 mash for the precipitation of calcium and magnesium. sodium sulfate and 0.4 May, h. soda After dissolving, 79, Om. H. halite sediment, 47.7 mA. clay-salt sludge and 204.0 ma.ch. a clarified solution containing, in wt.%: KC 20.7j NaCl 14.8; MgCl4, 0.8; CaCl2 0.7; 62.95. The resulting solution is fed to the crystallization of potassium chloride and drying to obtain 26.6 parts by weight. product of the following composition. Mas.%: KC1 90.3; NaCl 3.3; 0.1; Cac12 0.15; H20 6.15. The potassium chloride yield in this case is 96.5%.

Table 1 shows recovery rates for potassium chloride at

processing of ores in accordance with the prototype and the proposed method.

The table shows that the implementation of the method leads to an increase in the recovery of potassium chloride from ore and a commercial product for ores with a high content of calcium and magnesium chlorides.

The effect on the degree of recovery of potassium chloride from the leach solution is given in Table 2.

As a hot solution saturated with potassium and magnesium chlorides containing sodium sulphate and soda, it is possible to use the waste product of a glaeritic solution of potassium sulphate production by converting potassium chloride and sodium sulphate. Glaterite solution is governing, mn.% KC1 up to 15.5; Nad to 17.0; N, 4ZS04 to 3.8; NajCOj to 2.3; H20 the rest. It is fed to the stage of dissolving the ore immediately after the evaporators.

The proposed method makes it possible to increase the recovery of potassium from ore into a commercial product; allows to simplify the process by eliminating the stage of evaporation of liquors and reduce energy costs; allows the use of by-products, such as potassium sulphate production wastes, and improve environmental conditions by reducing waste

liquid waste. The use of the invention provides an increase in the yield of potassium chloride in comparison with the known method by 4-10% in the recording of the content of magnesium and calcium chlorides in the ore.

Claims (2)

1. A method for producing potassium chloride cs of slvinite ores with an increased content of calcium chlorides, magnesium and insoluble compounds, including two-stage leaching of crushed sylvinite by heating with a working stock solution to obtain a suspension, imitation of ielite and clay sludge, installation of the calcite and sludge, installation of the alite and clay slurry, installation of the alite and clay slurry, installation of the calcite sludge, installation of the alite and clay slurry, installation of the calcite sludge; , drying, characterized in that, in order to increase the degree of chloride recovery, and, in suspension before the release of halite and clay slime serves a saturated solution of potassium chloride and sodium at 110-1 5 C, containing sodium sulfate and soda in an amount of 0.3-3.86 and 0.4-2.26 wt.h. respectively. 2. A method according to claim 2, characterized in that glazerite solution, a waste product of potassium sulfate production by conversion of potassium chloride and sodium sulfate, is used as a saturated solution of potassium chloride and sodium at 110-115 ° C containing sodium sulfate cathode. Table 1 1623954 Table 2