SU497823A1 - Method of preparing strontium carbonate - Google Patents

Description

(54) METHOD FOR PRODUCING STRONTIUM CARBONATE

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The invention relates to methods for producing strontium carbonate from natural strontium sulphate celestine and can be used in the chemical industry, in particular, to produce a sufficiently pure strontium carbonate used in the electronics industry.

A known method of producing strontium carbonate by reductive calcination of natural strontium sulfate, water leaching of the obtained strontium sulfide melt, separation of the insoluble residue, and pacTBqDa strontium sulfide sodium carbonate, followed by separation and drying of the product. However, by this method there is a large loss of the target product with a separable insoluble 1 residue, as a result of which the product yield does not exceed 6O%.

The aim of the invention is to increase the yield of the target product,

For this, strontium natural sulphate is treated with a salt acid at a pH of 1.0-2.0 and a temperature of 50-70 ° C before reduction calcination and the solid is separated.

strontium sulphate solution; an insoluble residue after water leaching of molten sulphide water is also treated with hydrochloric acid to a pH of 1, O-1.5. The formed suspension is neutralized; dorH 7, O-9, O, the residue is separated and the resulting solution of strontium chloride is sent for treatment with sodium carbonate.

The proposed method i is carried out as follows.

Crusted celestine (natural strontium sulphate) is treated in an apparatus with: a salt hydrochloric acid stirrer, preferably 5-2O9 hydrochloric acid, at: pH 1.0-2.0 and temperature 50-70 0, preferably 60 ° С, for 4O-6O min. The resulting suspension is separated on a filter or in a settling tank. Solid sol separated from solution. Strontium Fat is washed and mixed with

carbon-containing reducing agent, for example coke, in a ratio of 3: 1 by weight). The mixture is calcined in a drum rotary with a furnace at 11OO-12OO ° C.

Strontium sulfide melted melt is ground with water in a ball mill, floor

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Additional water treatment in the reactor is carried out, and the resulting aqueous solution of strontium sulfide is separated from the insoluble residue in the sump or on the filter. An aqueous solution of strontium sulfide is mixed with an aqueous solution of sodium carbonate with a concentration of X 80–220 g / l at a final product of 5% compared with the stoichiometrically necessary for water over sulfate dada / -strontium to strontium carbonate. The precipitated carbonate of strontium is separated, washed with water and dried The insoluble residue, separated by the water leaching of strontium sulfide water, is treated with hydrochloric acid DORH of 1, 5. The resulting suspension, the liquid phase of which is a solution; strontium chloride, and the solid phase contains silicon dioxide, unrestored strontium sulfate, untransformed coke, etc., is neutralized with sodium hydroxide solution to pH 7, O, the suspension is separated, the insoluble residue is separated, strontium chloride solution is treated with sodium carbonate solution with a concentration of 180 -220 g / l, and the formed strontium carbonate precipitate is separated, washed with water and dried., Example 1. Celestine, previously ground to a particle size of 5 mm, containing 86% strontium sulfate and 12% calcium in terms of Sul fate calcinus g is fed in an amount of 1 ton to a pee torus with a capacity of 2.67 m, equipped with a stirrer and a raver jacket, to which at the same time 1.41 tons of hydrochloric acid are fed. Treatment of celestine is carried out for 45 minutes at 60 ° C and pH 1 2 After treatment, the suspension is transferred to a suction filter with an area of 0.34 m, where it is separated. The liquid phase, which is a solution of calcium chloride, is removed from the stock. The precipitate, containing 97.2% strontium sulphate and 0.68% calcium sulphate, is washed with water, mixed with 0.295 tons of coke breeze and burned in a rotary drum kiln 8 Om in length and 0.5 m in diameter at a temperature of 1135 ° C. . The resulting strontium sulfide melt is crushed in a ball mill, where the wash water is simultaneously supplied after the secondary treatment of the water in the melt in the reactor with a BETTER and heating. Wash water is supplied in the amount of 4.38 t / h at 0.73 t / h ppava. The resulting suspension is separated on a vacuum filter with an area of filtrates and 0.5 m. The slurry in the amount of 0.59 tons per hour after separation is subjected to secondary water treatment in a stirred reactor, to which 4.38 tons per hour of process water is added.

After 40 minutes of treatment, the suspension is separated and a strontium sulfide solution with a concentration of 9.40% and a water-insoluble residue are obtained.

An aqueous solution of strontium sulfide in the amount of 4.280, t / h is treated in the reactor with an aqueous solution of sodium carbonite with a concentration of 17.6%, taken in a Kt amount of 2.12 t / h. The precipitated carbo, nata strontium is separated on a drum vacuum filter, washed by repulpation and a strontium carbonate paste is obtained with a moisture content of 50% in an amount of 0.87 O ton / hour. The resulting solution of sodium sulfate with a concentration of 4.4% is removed from the process. The strontium carbonate paste is dried in a rotary drum dryer with a length of 8.0 m and a diameter of 0.5 m, after which 0.430 tons of strontium carbonate containing 97.5% of the basic substance and 0.57% of calcium in terms of calcium carbonate is obtained. An insoluble residue in an amount of 0.458 tons with a moisture content of 26%, obtained by water leaching of strontium sulfide, is treated in a reactor with stirring and steam heating at 75 ° C with hydrochloric acid of 27.5% taken in an amount of 0.31 tons / necessary to bring the pH of the suspension to 1.0, and technical. 1.38 tons of water. The resulting acid is neutralized with caustic soda solution taken in an amount of 0.02 tons, thus bringing the pH of the suspension to 7.7. The resulting suspension of strontium chloride is separated on a filterpress. The separated insoluble residue with a moisture content of 35% in an amount of 0.308 tons is removed from the process. A solution of sodium carbonate with a concentration of 17.6% in an amount of 0.828 tons is added to the strontium chloride solution at a concentration of 9.45% in an amount of 0.231 tons / h. h The treatment with sodium carbonate is carried out at 8 ° C in a reactor with a stirrer and steam heating. The resulting suspension is directed to a drum vacuum filter, where the stronpi carbonate paste is separated in an amount of 0.412 tons. The resulting paste is washed, repulped and dried in a drum rotary dryer, after which approximately 2.05 tons of the desired product containing 97.5% is obtained strontium carbonate and 0.66% calcium in terms of calcium carbonate. The separated solution of sodium chloride is removed from the process. In total, 0.636 tons of strontium carbonate are obtained during celestine processing. The yield of the desired product is 90%. The calcium content in the product in terms of strontium carbonate is 0.5 to 9%.

Claims (1)

Claims. The method of obtaining strontium carbonate by reductive roasting of natural strontium sulfate, water leaching of the obtained strontium sulfide melt, separating the insoluble residue, treating the strontium sulfide solution with sodium carbonate, followed by separating and drying the product, in order to increase the yield of the target product, and naturally dissolve the sulfate. Before restoration roasting, treat with hydrochloric acid at pH 1.0-2.0 and temperature 5 ° -70 ° C and solid strontium sulfate is separated from the solution The opium residue after water leaching of strontium sulfide is also treated with hydrochloric acid to a pH of 1.0-1.5, the resulting suspension is neutralized to pH 7, the insoluble residue is separated, and the resulting solution of strontium chloride is sent to sodium carbonate treatment