SU986855A1 - Process for producing potassium chloride - Google Patents

Description

(54) POTASSIUM CHLORIDE PROCESS

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The invention relates to chemical technology of inorganic substances and can be used to produce potassium chloride in the processing of magnesium-containing sylvinites.

There is a known method for processing sylvinites, according to which sylvin is emptied with a hot mother liquor, halite sediment and clay slurry are separated, lye is cooled, and potassium crystals are separated from the Cl 3 mother liquor.

The disadvantage of this method is the need to discharge part of the mother liquor due to the accumulation of magnesium chloride in them, which leads to unnecessary loss of useful components and to the pollution of the environment.

The closest in technical essence and achievable effect is the method of producing potassium chloride from magnesium-containing sylvinites, including the combining of ore with combustible alkali, separation of halite sludge and

clay slurry, cooling liquor and sc. division of potassium chloride, a two-stage evaporation of a part of the mother liquor to obtain sodium chloride in the first stage, and a chlorine magnesium solution in the second stage, and artificial sylvinite, which is returned to the C2 leaching.

The disadvantage of this method is -. removal from the process of a significant amount of potassium chloride with chlor-magnesium

10 solution, which reduces the extraction of potassium to potassium chloride.

The aim of the invention is to increase the yield of potassium chloride.

The goal is achieved by

15 that in the process of producing potassium chloride from magnesium-containing sylvinites by leaching them with hot liquor, separating halite sediment and shale, crystallizing potassium chloride,

Claims (2)

The 20 varki mother liquor and the separation of sodium chloride, the mother liquor, before evaporation, is mixed with sodium hydrogen phosphate solution in an aquimolar ratio, the solution is separated, and after the evaporation and separation of sodium chloride, the solution is sent to potassium chloride crystallite. The treatment of the mother liquor obtained at the stage of crystallization of potassium chlorine with a solution of sodium hydrogen phosphate makes it possible to precipitate and separate the magnesium in the form of slightly soluble magnesium phosphate. In this case, magnesium ions are replaced by sodium in the mother solution. This allows, by evaporation, to remove sodium chloride from such a solution and then direct it to crystallization to extract potassium from it as potassium chloride. In contrast to the present method, the mother liquor is not removed from the process, and through the stage of the separation of magnesium in the form of phosphate and sodium chloride, it returns to crystallization of potassium chloride. This gives practically complete extraction of potassium from it into the marketable product, i.e. in potassium chloride. Sodium hydrogen phosphate is taken in a quantity that provides an equimolar ratio of NctjHPC to Nc (2HP (; M less than 0.95) and there is a non-exudation of magnesium from the excess mother liquor, which leads to a deterioration of the process of potassium chloride due to the co-crystallization of sodium chloride. "2 HPQjlMtj more than one leads to the fact that in the mother solution after the separation of magnesium phosphate remains part of the phosphorus, which precipitates at the stage of crystallization of potassium chloride. At the same time, the quality of potassium chloride decreases and sodium phosphate is increased. Potassium chloride is obtained as follows: sylvinite and dissolving liquor are fed to hot leaching. Halite precipitate is removed from the resulting solution, which is deposited after nponibic, and clays, which are removed from the process after washing. Potassium chloride is separated from the clarified solution by cooling the solution, thickening, centrifuging and drying. The main part of the mother liquor obtained after separation of potassium chloride is directed to the preparation of dissolving liquor, the rest of the mother liquor is mixed with sodium phosphate solution and the precipitated magnesium phosphate is separated. The demagnetized solution, which is potassium and sodium chlorides, is evaporated; the beginning of crystallization of potassium chloride, the precipitated sodium chloride is separated, and then sent to the crystallization of potassium chloride. Example. 1O, 0 kg of sylvinite composition, weight. %: COP € 25.50; NaCB 68.25; , 55; the insoluble residue 5, OO and HgO 0.7O is dissolved at a temperature of 25–7 kg of dissolving liquor of the following composition, weight,%: KSE 9.14; NotCei4,32; MqjCe24 07 and 72.47. After dilution, 7.0 kg of halite sediment, 2.1 kg of sludge and 23.1 kg of a saturated solution of the following composition are obtained: weight. %: KSE 18.45, NdCB 14.2O; M (fCB 4.25; and H2O 63, U, which is mixed with one stripped off of the solution obtained at the stage of separation of sodium chloride. Then the mixture of solutions is cooled to 25 ° C. After cooling, 2.7 kg of potassium chloride containing, wt.% : KCC 9O, 60; Nace 3.6O; 0.13; H2O 5.67 and 21.0 kg of the stock solution of the following composition, wt.%: 9.13; N "Ce .14.96; McjCe24.33 and HjO 71.58. The mother liquor is divided into two parts: 19.7 kg is used to prepare a solution of yush, its liquor, and 1.3 kg is used for magnesium precipitation. 0.160 kg of a 50% sodium hydrogen phosphate solution is also used for magnesium deposition , i.e. the ratio of Ma2HP04; ms comp. Aval 0.95. Magnesium deposition is carried out at 6 ° C. The precipitated amount of O, NO kg is washed on; filtrate with water (0.01 kg). Its composition is as follows, wt.%: 19.02; , 1O; No) 0.15; every 0.19; and EU 43.26. The mother liquor after separation of magnesium phosphate is 1.36 kg and has a composition, weight. %: KSE 8,82; NaCe 19,12; . 0.06; , 05; and 71.94. It is evaporated at 11 ° C until the removal of 0. 64 kg of water. The resulting suspension is divided into 0.18 kg of sodium chloride composition; weight. %: NaCC 94.00; Xe 0.95; Noo 5.05; and 0.54 kg of one stripped off solution of the composition, weight. %: No (CC17.00; KSv 22.00; 0, O5; Hf 6O, 95; which is directed to the crystallization of potassium chloride. Example 2: 1.3 kg of mother liquor from the crystallization stage of potassium chloride j prepared by ppimer 1 is mixed with 0.167 kg of a 5O-° solution of sodium hydrogen phosphate, i.e. the ratio of NO H (j is 1: 1. The precipitation is carried out at 60 ° C. The precipitate formed in an amount of 0.112 kg is washed on the filter with water (O , O1 kg). Its composition is as follows, wt.%: MtjO 18.95; PjOj 33.08; KO, 1O; Ma O, O9; se 0.15; HnO 43.5O. The mother liquor after separation of magnesium phosphate is &; lt 1.36 kg and has a composition, weight,%: Ke 8.80; NdCe 19 0 7;, 05; P2OjO, 05; and 72.04. It is evaporated before the removal of 0.64 kg. Using the invention provides an increase in potassium chloride output by 0.01 ton per Ut of processed ore, i.e. by 0.37%. In addition, the yield of fertilizer is increased by the release of magnesium phosphate, which can be used as a fertilizer directly or can be used as a raw material for the production of magnesium ammonium phosphate, which is a complex three-way fertilizer. According to the proposed method, a chloromagnesium solution is not produced, the marketing of which is difficult. The annual economic effect from the introduction of the invention will be 380 thousand rubles. Claims The method of producing potassium chloride on magnesium-containing sylvinites by & 55 dy The suspension obtained is divided into 0.18 kg of sodium chloride, the composition of wt.% NaCe is 94.07; KSE 1.01; HgO 4.92 and 0.54 kg of one stripped off solution of the composition, weight%: No (Ce 16.93; DCC 22.07; MtfCfg 0.04; HjO 6O, 96, which is directed to the crystallization of potassium chloride. For comparative data In parallel, the processing of magnesium-containing sylvinites is carried out according to a known method. Based technical and economic indicators of the known and proposed methods are given in Table 1. Their leaching with hot liquor, separating halite sludge and clay slurry, crystallizing potassium chloride, evaporating a magnetic solution and separating by that that, in order to increase the output of potassium chloride, the mother liquor is mixed with an equimolar ratio of sodium hydrogen phosphate solution, the precipitate is separated, and after evaporation and separation of sodium chloride, the solution is directed to the crystallization of potassium chloride. attention in the examination 1.Pozin M, E. Mineral salt technology, 1974, V. 1, pp. 146-149. 2.Pechkovsky V.V., Technologists of Potassium Fertilizers. Minsk. Vysheysha school. 1978 c. 191-193 (prototype).