SU710919A1 - Method of preparing potassium sulfide - Google Patents

Description

one

The invention relates to a method for producing potassium sulfide, which is used in the manufacture of dyes, potash, and other fields of the chemical industry.

Methods are known for producing potassium sulfide by reacting metallic potassium with elemental sulfur at 200-300 ° C in vacuum, or by reacting elemental sulfur with metallic potassium dissolved in liquid ammonia (1.

The lack of methods is the high cost of potassium sulfide due to the use of expensive starting reagents.

The closest in technical essence to the present invention is a method for producing potassium sulfide by reducing K2SO4 with natural gas at 800-950 ° C.

The drawbacks of the process are the long process time and low product yield (52.2%), due to the melting process, the need to crush the melt and the difficulty of separating potassium sulphide from unreduced potassium sulphate.

Pel invention - increase the yield of the target product.

The goal is achieved by the fact that potassium sulfate is taken in a mixture with magnesium oxide in a weight ratio of MDO: K2S04 equal to 0.7-2.3 and subjected to reduction by natural gas of schzi 800-1050 ° C.

The method is carried out as follows.

) After drying, magnesium oxide and potassium sulfate are shifted in a weight ratio of 0.7-2.3 and sent to a rotary or shaft kiln, where at 800-950 ° C K2S04 is reduced with natural gas or hydrogen or carbon monoxide, or blends. The process exhaust gases are cooled in heat exchangers and directed to the exhaust.

Potassium sulphide is leached from the solid products after cooling. Magnesium oxide is separated from the solution, c) lined and returned to the process. From the solution, K2S is crystallized, which is packaged as a finished product after the sunja. The reduction of K2SO4 with natural gas, hydrogen, and carbon monoxide begins at 750–8CU ° C, but the rate of the process at these temperatures is very small. Increasing the calcination temperature leads to the melting of a solid base as a result of the formation of a KS-KiSO4 eutectic mixture. The presence of a liquid base leads to a decrease in the reaction surface and a decrease in the rate of the process. The addition of magnesium oxide to potassium sulfate makes it possible to increase the calcining temperature of 4 and, with a MdO: KjSOa ratio of 0.7 2.3, the charge in the temperature range of 800-1050 ° C remains solid and easily crushed. The choice of magnesium oxide is due to its refractoriness, chemical resistance and low cost. The degree of conversion of potassium sulfate to KjS is 98.5-99.5%. The effect of temperature, time, and feed rate of the reducing agent on the degree of reduction of K2SO4 to the reduction is given in the table.

As can be seen from the table, an increase in the amount of magnesium oxide in the sulphate charge allows the reduction process to be carried out at a higher temperature, which also reduces its duration. flow. The mixture in which the ratio MDO; KzZoZD 2,3, at 1050 ° С in 7 minutes is almost completely reduced and exceeds almost

571

11% level of recovery of Ishkhta with respect to MDO: K SO4 1.4. In this mode, recovery of the charge by the MDO: K2S 0.7 ratio is much worse due to the melting of the residue. Already with the degree of sulLate reduction in this mode, it is about 17% lower than at 950 ° C. With a MdO ratio: KjSOA 0.7, the almost complete recovery of K2SO4 is achieved in 15 minutes at 950 ° C; with a MDO: K2SO4 ratio of 1.4, the same level is reached at 1000 ° C in 10 minutes and at a ratio of 2.3 at 1050 ° C in 7 minutes.

These data indicate that in order to shorten the process, it is necessary to reduce the sulfate at higher temperatures, provided that the formation of the liquid phase is prevented. The latter condition is provided by the addition of magnesium oxide to the mixture.

The yield of potassium sulphide is determined by the degree of conversion of K2SO4. The higher it is, the higher the output of potassium sulfide. At the same duration of the process, the sulphide consumption, as well as the conversion rate, increases with higher temperatures, and, consequently, with an increase (W content - MdO in the sulphate solution.

An increase in the MgO content in the charge above the weight ratio of MgO: K2S04 2.3 is impractical because the content of K2SO4 in the charge decreases, which leads to a decrease in the rate of reduction process. So, with a MDO: K2SO4 weight ratio of 3.5, the reduction rate at 1050 ° C is Liha 89%, which is 10% lower than when the charge was reduced with a ratio of 2.3.

A decrease in the ratio below 0.7 is also impractical because of the decrease in the process rate and its transition to the liquid mode (see table).

. Example. Anhydrous K2S04 (5.9 g) and WgO (4.1 i) are combined at a ratio of 0.7, loaded into the reactor, and reduced with natural gas at 800-825 ° C. After 20 30 msh-1 products are unloaded from the reactor,

they cool and leach out of them sulyide potassium. Magnesium oxides are separated from the solution by filtration. The solution is dried and potassium sulphide is obtained. As a result of the operations, 4.1 g of returnable MDO and 3.7 g are obtained.

sulphide. The yield of the target JiponyKia is 84.4%.

Example 2. 5.2 g of KjSOj and 4.8 MgO are mixed (oTHOHieiKe MgO: K2S04 0.9: 1, loaded into the reactor and reduced at 925-950 ° C for 15-20 minutes. After separation of the components of the residue, 4.8 g of MgO and 3.2 g ;;) potassium lfida. The yield of the target product is 92.3%.

P m and m p p 3. 4.2 g of K2S04 and 5.8 g of MgO (a ratio of MgO: 2504 1.4) are mixed together; : are loaded into the reactor and reduced with natural gas at 975-1000 ° C for 10-15 minutes. After diluting the residue components, 5.8 g of MgO and 2.6 g of potassium sulfide are obtained. The yield of the target product is 99.2%.

Example (f mep 4. 5 g of K2SO4 and 11.5 g of MaO are mixed (2.3), placed in a quartz reactor with a porcelain diaphragm. The reactor is installed vertically in an electric furnace, after which the system is washed with an inert gas (nitrogen). The furnace is heated to J050 ° C, when this temperature is reached, the natural gas supply is turned on. After 7-8 minutes, the system is flushed with an inert gas, the heating is turned off, the furnace is cooled, then the reduced residue is removed. After extracting K2S from the residue, the solution is separated from the MDO, its evaporation and drying products 1.5 g MCO and 3.1 g. You the progress of the target product is 99.3%,

Formula and 3 about the system

1. A way to get a sperm kaln by Bosstanut of potassium potassium thuthtate by gaseous reduction at high temperatures, so that potassium sulphate is mixed with magnesium oxide in a weight fraction of MgO in order to achieve the yield of the target product. : K2S04, 0.7-2.3.

 2. Sposs; 5 in accordance with Clause 1, of the TI and UI and with the fact that the process is conducted at 800-1050С.

Sources of information taken in charge during examination

1.Ripznu R., Chet I. I. Inorganic Chem., T. 1, M., Mir, 1971, p. 106

2.X- (urn.t7 of applied chemistry, 1959, 32. No. 1,;. 216 (prototype).

Claims (2)

1. A method of producing potassium sulfide by reducing potassium sulfate by gaseous reduction at high temperature, with the aim that, in order to increase the yield of the target product, potassium sulfate is taken in a mixture with magnesium oxide in weight the ratio of MgO: K ₂ SO _4> equal to 0.7-2.3. '2. The method according to π. 1, characterized in that the process is conducted at 800-1050 ° C.