SU1150224A1 - Method of reprocessing potassium polymineral ore with obtaining potassium nitrate - Google Patents

Abstract

1. METHOD OF PROCESSING OF POTASSIUM POLYMINERAL ORE WITH OBTAINING POTASSIUM NITRATE, including decomposition of ore by 10-20% nitric acid, neutralization of the solution with lime milk, gypsum separation. evaporating the neutralized solution with separation of sodium chloride and salting out potassium nitrate with methanol while cooling in the presence of potassium chloride, characterized in that, in order to reduce the consumption of nitric acid while maintaining a high degree of potassium recovery, the ore is leached beforehand, the solid residue is separated from the solution and suspended sludge, nitric acid decomposition is subjected to a solid residue while maintaining W: T

Description

ate

o you

YU

four

The invention relates to the processing of sparingly soluble in aqueous solutions of polymeric potash ores for highly concentrated complex fertilizers and can be used in the production of mineral fertilizers.

A known method of processing polymineral potash ore into nitrogen-potassium fertilizer by washing it out of sodium chloride, decomposing it with nitric acid, neutralizing the resulting suppression, separating the gypsum, evaporating the neutralized solution to form a melt, and then granulating the fertilizer 1.

However, in the processing of potash ores containing easily soluble potash minerals, in the process of washing, potassium and magnesium salts are also transferred to the solution along with sodium chloride.

The closest in technical essence and the achieved result to the proposed method is the processing of polymineral potash ore to potassium nitrate, including nitric acid decomposition, excretion of sodium chloride, neutralizing the nitrate solution of lime milk, separating the gypsum formed and clayey mud to form a filtrate and excreting nitrogen fertilizer. methanol and potassium chloride 2.

The disadvantage of this method is that in the presence of nitric acid, all ore, including readily soluble minerals, is decomposed.

In addition, the composition of polymineral ore includes up to 15-30% of clay impurities, which partially interact with nitric acid. Therefore, to ensure the maximum release of potassium and nitrogen into potassium nitrate, the dissolution of the ore must be carried out with a 15-20% excess of nitric acid with respect to soluble sulfate ions.

The purpose of the invention is to reduce the consumption of nitric acid while maintaining a high degree of potassium recovery.

This goal is achieved in that according to the method of processing potassium mineral mineral ore to produce potassium nitrate, including decomposition of ore by 10-20 ° / o-nitric acid, neutralizing the solution with lime milk, separating gypsum, evaporating the neutralized solution to release sodium chloride, and salting out potassium nitrate with methanol while cooling in the presence of potassium chloride, the ore is preliminarily leached, the solid residue is separated from the solution and sludge suspension, nitric acid

a solid residue is decomposed while maintaining W: T (15: - 2.5): 1; before the neutralization stage, the solution is shifted with the product of nitric acid decomposition and nitric acid, taken in an equivalent amount to sulfate ions, and the slits are washed and the washing solution are leached to the ore leaching stage.

0 Leaching is carried out at a ratio of ore and leaching solution equal to 1: (1.7-2.1).

Reducing the consumption of a nitric acid solution below 1.5 (as can be seen from Table 1) leads to incomplete dissolution of the residue and loss of valuable components of the ore, and an increase of more than 2.5 leads to an increase in the cost of instrumentation due to the formation of a large amount of dilute solutions. A decrease in the concentration of nitric acid below 10% and an increase of more than 20% (as can be seen from Table 2) leads to a decrease in the degree of dissolution of the residue.

five ""

Irie reducing consumption neutral

the washing solution is lower than 1.7; the degree of dissolution of soluble minerals is insufficient, which leads to the formation of a large amount of insoluble residue and, as can be seen from the table. 1, requires an increased cost of equipment for the stage of nitric acid decomposition of the residue. In addition, the degree of separation of the clay slurry from the ore at the same time is low, it enters with the residue in nitric acid

environment and (as can be seen from table. 3) causes an increase in consumption of nitric acid. An increase in the consumption of a solution of more than 2.1 leads to an increase in the equipment volume at the stage of dissolving ore in a neutral solution due to the formation of

Avg.

Reducing the consumption of nitric acid for the processing of ore is due to the fact that clay impurities in the process of dissolving

in a neutral environment, the output from ore is 83-88%. In the process of nitric acid decomposition of ore, clay impurities partially interact with nitric acid. To maintain an equivalent equality between hydrogen and sulphate ions in a saturated solution, it is necessary to introduce a 15-20% excess of nitric acid relative to soluble sulphate ions of the ore. Therefore, the separation of clay impurities in a neutral medium allows the residue to be decomposed with nitric acid,

containing only 12-17% of clay impurities of ore, which reduces the neutralization of the acid and, as can be seen from the table. 2, reduces its consumption of ore decomposition.

Table 1

Example 1. 400 g of polymineral potash ore composition, May. %: K 8.45; Mg 4.56; Ca2 1.09; Na 13.71; C1 26.77 23.39; and about. 13.30; 8.73-dissolved in 680 g of the solution obtained after washing the clay residue of the composition, May. % K 1.51; Mg2 1.77; Ca 0.04; Na 1.96; C G 8.06; SO 2.13 - at 8.0 ° С for 20 min. The slurry slurry slurry is separated by decantation. 91.7 g of an insoluble residue are obtained, May. %: K 8.38; Mg2 6.36; 2.42; Na 10.73; SG 17.60; SP 39.81; and about. 8.52; 6.18.

The slurry slurry is treated with 5 g of a 0.25% polyacrylamide solution, clarified, decanted clarified solution, the thickened slurry is filtered. Get 910 g of a saturated solution of the composition, May. %: K 3.75; Mg 2.54; Ca 0.04; Na 6.25; SG 15.78; 6.44.

Langbeinite-polyhalite residue

crushed to a grain size of 1 mm and dissolved in 183 g of a 15% aqueous solution of nitric acid at 80 ° C for 30 minutes. The resulting solution was mixed with a saturated solution and 153 g of 55 / nitric acid was added. The mixture obtained is neutralized with 228 g of milk of lime containing 28 / o Ca (OH) g. The precipitated gypsum is separated by filtration, yielding 1340 g of the filtrate of composition, May. / o: K 3.03; Mg 2.09; Ca 0.26; Na - "- 4.83; SP 1.57; SOV 0.12; NOa 8.11. 720 g of water are evaporated from the filtrate at 100 ° C, and the crystallized sodium chloride (155 g) is separated by filtration. One stripped off solution composition, May. ° / ot K 8.55; Mg2 5.67; Ca 0.14; 1.02; C1 13.24; SO2 / (0.06; NO5 22.44 — mix 184 g of 27/1 solution of potassium chloride, cool to 30 ° C, add 360 g of methanol, and cool to 0 ° C. Filter off the filter, wash with methanol and eat, get 165 g of potassium nitrate with 100.4 / o.

Example 2. 400 g of polymineral potash ore in Example 1, the solution is 760 g of solution in a mixture of washing sludge. Supension of clay sludge is decanted, get 82.3 g of insoluble residue composition, May. / o K 9,61; Mg2 + 7.53; 2.70; Na + 4.82; SG 8.91; SO 46.04; and. about. 9.52; 19.48. The supersy of the clay slurry is separated, and 980 g of the most endeavored eoetava are obtained, May. o / o: K 3.72; Mg 2.48; 0.03; Na 6.22; SG 15.69; 6.10.

The non-distilled pot is crushed to a particle size of less than 1 mm and dissolved in 165 g of a 15% nitric acid solution. The resulting solution is mixed with a saturated solution and 157 g of 55 / v / v nitric acid is added. The mixed solution is neutralized with 228 g of 28 / liter milk of lime, the separated gypsum is separated by filtration, 1380 g of filtrate are obtained, from which 750 g of water are evaporated. The precipitate of sodium chloride (159 g) is separated by filtration, and 471 g of a solution of the composition are obtained, in May. %: K 8.76; Mg 6.04; 0.18; Na 0.98; SG 14.96; 0.07; NOj 21.64. 184 g of a 27% potassium chloride solution is added to the evaporated solution, cooled to 30 ° C, 360 g of methanol is added and cooled to 0 ° C. The suspension is filtered, the precipitate is washed with methanol and dried, to obtain 167 g of potassium nitrate with a purity of 98.4%. Example 3. 400 g of polymineral potassium ore composition according to example 1 is dissolved in 840 g of solution after washing the clay slime. The slurry slurry is separated by decantation. 75.8 g of insoluble residue are obtained, May. / o: K 10.34; Mg2 8.01; 3.00; Na- 2.02; SG 5.01; SOV 48.97; n about. 8.69; Ng.O. 13.96. Slurry slurry slurry is separated; 1064 g of a saturated solution of the composition is obtained, May. %: K 3.45; 2.45; Ca2.0.04; Na 6.32; SG 15.66; SO 6.01. The undissolved residue is crushed to a particle size of less than 1 mm and dissolved in 152 g of a 15% nitric acid solution. The resulting solution is added to a saturated solution, to which 157 g of 55% nitric acid is also added. The offset solution is neutralized with 228 g of 28% milk of lime. The resulting suspension is filtered, 1440 g of filtrate are obtained, from which 800 g of water are evaporated. The precipitate of table salt (1b2 g) is separated by filtration, and 478 g of the composition solution is obtained, May. %: K 8.85; Mg 6.53; Ca2.0.10; Na 0.97; SG 15.92; 0.07; NOa 22.26. 184 g of a 27% potassium chloride solution is added to the evaporated solution, cooled to 30 ° C, 360 g of methanol is added and cooled to 0 ° C. The suspension is filtered, the precipitate is washed with methanol and dried, to obtain 162 g of potassium nitrate with a purity of 98.4%. The proposed method, in comparison with the known ones, allows to significantly reduce the consumption of nitric acid while maintaining a high degree of potassium recovery, moreover, its implementation reduces the amount of expensive corrosive equipment operating in nitric acid media by more than 4 times.

Claims (2)

1. METHOD FOR PROCESSING POTASSIUM POLYMINERAL ORE WITH PRODUCTION OF POTASSIUM NITRATE, including decomposition of ore with 10-20% nitric acid, neutralization of the solution with milk of lime, separation of gypsum, evaporation of the neutralized solution with evolution of sodium chloride and salting out of potassium chloride in the presence of potassium methanol , characterized in that, in order to reduce the consumption of nitric acid while maintaining a high degree of potassium extraction, the ore is preliminarily leached, the solid residue is separated from the rast a thief and suspended sludge, a solid residue is subjected to nitric acid decomposition while maintaining W: T = (1.5–2.5): 1, before the neutralization step, the solution is mixed with the nitric acid decomposition product and nitric acid taken in an equivalent amount to sulfate ions, and the sludge is washed and the washing solution is sent to the ore leaching stage. 2. The method according to π. 1, characterized in that the leaching is carried out at a ratio of ore and wash solution of 1: (1.7-2.1).