RU2565681C1 - Method of producing barium chloride dihydrate - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method includes decomposing molten barium sulphide with barium chloride solution obtained by mixing a saturated mother solution after separating barium chloride crystals with 40% hydrochloric acid in a ratio which provides the content of hydrochloric acid in the mixture of 10-11% and the content of barium chloride of 20-21%. The solution is separated from the undissolved sludge and barium chloride dihydrate is extracted by cooling the neutral solution.

EFFECT: invention simplifies the process by excluding the solution evaporation step.

Description

The present invention relates to a technique for producing barium chloride by decomposition of a barium sulfide melt by a solution of hydrochloric acid and crystallization of barium chloride by cooling the solution.

According to the known method [1], the melt for decomposition is served in 13-15% of the mass. hydrochloric acid until a slightly alkaline reaction is achieved with an excess of barium sulfide in an amount of 15-20 g / l. This technology is used in existing enterprises and adopted by us as a prototype. After decomposition, the sludge is separated in a centrifuge, and in the resulting solution, the excess barium sulfide is neutralized by the addition of hydrochloric acid to pH 4-7. Next, the solution is evaporated to achieve a proportion of barium chloride of 40-41% of the mass. (550-600 g / l). After cooling the evaporated solution to 20 ° C, precipitated crystals of barium chloride two-water are separated in a centrifuge.

Since up to 3 tons of water is evaporated per 1 ton of marketable salt, the big disadvantage of this technology is the high energy costs associated with the consumption of steam for evaporation, and significant capital costs for the organization of the evaporation department. The use of a more concentrated hydrochloric acid solution for the decomposition of barium sulfide, which would reduce the steam consumption for evaporation, is unacceptable due to an increase in the precipitation of sulfur in the precipitate and losses of the latter with sludge. Therefore, in the current production, technical hydrochloric acid is diluted with water and later the costs of evaporating this water are borne.

Other well-known methods [2, 3] solve the problem of obtaining a part of the product of reactive qualification (“PSA” and “H”) by washing the crystals on the filter [2] or introducing into the solution before crystallization an additive of a substance that regulates supersaturation and reduces the formation of uterine inclusions in intergrowths of crystals of barium chloride [3]. In both cases, the need for evaporation before crystallization by the proposed techniques is not excluded and such a task is not posed.

The objective of the invention is, while maintaining the desired degree of decomposition of the melt, obtaining, at the stage of decomposition, a solution of barium chloride of an increased concentration sufficient to isolate salable salt without evaporation of the solution before crystallization of barium chloride.

This goal is achieved in that the decomposition of barium sulfide melt is carried out with a hydrochloric solution of barium chloride obtained by mixing a saturated mother liquor after separation of crystals of barium chloride with 40% hydrochloric acid. In this mixture, the concentration of free hydrochloric acid of 10-11% and barium chloride of 20-21% of the mass.

Example 1

1 part by weight of barium sulfide melt containing 85% of barium sulfide, 10.2% of barium carbonate and 1.9% of substances insoluble in hydrochloric acid is treated at a temperature of 100-105 ° C for 120 minutes with 3 parts by weight of hydrochloric acid chloride solution barium containing 9% of the mass. hydrochloric acid and 21% of the mass. barium chloride. After 120 minutes of decomposition, 0.049 parts by weight of sludge with a proportion of barium compounds in it of 3.5% are separated on the filter, and sulfur is absent. The filtered solution was neutralized to pH 6 by adding 0.05 parts by weight of 40% hydrochloric acid, cooled to 20 ° C, and 0.96 parts by weight of precipitated crystals of barium chloride were separated on a filter.

Example 2

Under the same conditions, 1 part by weight of the melt is treated with 2.9 parts by weight of a hydrochloric solution of barium chloride containing 10% by weight. hydrochloric acid and 21% of the mass. barium chloride. Upon completion of the decomposition of the melt, 0.031 weight parts of the sludge is separated on the filter with a share of barium compounds in it of 0.6% and sulfur compounds - absence. The filtered solution was neutralized to pH 6 by adding 0.05 parts by weight of 40% hydrochloric acid, cooled to 20 ° C, and 1.03 parts by weight of barium chloride two-water was separated on the filter.

Example 3

Under the same conditions, 1 weight part of the melt is treated with 2.8 weight parts of a hydrochloric solution of barium chloride containing 11% of the mass. hydrochloric acid and 21% of the mass. barium chloride. Upon completion of the decomposition of the melt on the filter, 0.032 weight parts of sludge is separated with a share of barium compounds of 0.5% and sulfur compounds - absence. The filtered solution was neutralized to pH 6 by adding 0.05 parts by weight of 40% hydrochloric acid, cooled to 20 ° C. and 1.06 parts by weight of barium chloride two-water chloride were separated on a filter.

Example 4

Under the same conditions, 1 weight part of the melt is treated with 2.7 weight parts of a hydrochloric solution of barium chloride containing 12% of the mass. hydrochloric acid and 21% of the mass. barium chloride. Upon completion of the decomposition of the melt, 0.086 weight parts of sludge is separated on the filter with a share of barium compounds of 0.2%, sulfur compounds - 20.6%. The filtered solution was neutralized to pH 6 by adding 0.05 parts by weight of 40% hydrochloric acid, cooled to 20 ° C. and 1.06 parts by weight of barium chloride two-water chloride were separated on a filter.

Example 5

Under the same conditions, 1 part by weight of the melt is treated with 2.9 parts by weight of a hydrochloric solution of barium chloride containing 10% by weight. hydrochloric acid and 19% of the mass. barium chloride. Upon completion of the decomposition of the melt on the filter, 0.034 weight parts of sludge is separated with a share of barium compounds of 0.5% and sulfur compounds - absence. The filtered solution was neutralized to pH 6 by adding 0.05 parts by weight of 40% hydrochloric acid, cooled to 20 ° C, and 1 part by weight of barium chloride two-water was separated on the filter.

Example 6

Under the same conditions, 1 part by weight of the melt is treated with 2.9 parts by weight of a hydrochloric solution of barium chloride containing 10% by weight. hydrochloric acid and 20% of the mass. barium chloride. Upon completion of the decomposition of the melt, 0.036 parts by weight of the sludge are separated on the filter with a share of barium compounds of 0.5% and sulfur compounds — absence. The filtered solution was neutralized to pH 6 by adding 0.05 parts by weight of 40% hydrochloric acid, cooled to 20 ° C. and 1.05 parts by weight of barium chloride two-water chloride was separated on a filter.

Example 7

Under the same conditions, 1 part by weight of the melt is treated with 2.9 parts by weight of a hydrochloric solution of barium chloride containing 10% by weight. hydrochloric acid and 22% of the mass. barium chloride. Upon completion of the decomposition of the melt, 0.039 parts by weight of sludge are separated on the filter with a share of barium compounds of 0.6% and sulfur compounds - absence. The filtered solution was neutralized to pH 6 by adding 0.05 parts by weight of 40% hydrochloric acid, cooled to 20 ° C. and 1.08 parts by weight of barium chloride two-water chloride were separated on a filter.

Thus, when barium sulfide melt is decomposed with a barium chloride hydrochloric acid solution containing 10-11% free hydrochloric acid and 20-21% barium chloride, the barium sulfide melt is completely decomposed with barium chloride leaving the melt in a solution of 98.6-99% and without sedimentation into the sulfur slurry (examples 2, 3, 6).

When the concentration of free hydrochloric acid in hydrochloric acid solution of barium chloride is less than 10%, the yield of barium chloride from the melt into the solution decreases and is 96% at a concentration of 9% hydrochloric acid (example 1).

When the concentration of free hydrochloric acid in a hydrochloric acid solution of barium chloride is more than 11%, a part of the hydrogen sulfide is bound to precipitate elemental sulfur, which is deposited and removed with sludge (example 4).

When the proportion of barium chloride in the hydrochloric acid decomposition solution is less than 20%, the yield of crystals of barium chloride decreases.

When the proportion of barium chloride in the hydrochloric acid decomposition solution is less than 19%, the yield of the product is 92% of the required (example 5).

When the proportion of barium chloride in the hydrochloric acid decomposition solution is more than 21%, the yield of barium chloride from the melt into the solution decreases. So, at 22% barium chloride in the decomposition solution, it is 98%. At the same time, the crystal yield exceeds the required amount from the incoming barium with melt (example 7).

The proposed method allows for the complete decomposition of the melt of barium sulfide with the release of barium into the solution by 98.6-99% to exclude the stage of evaporation of the neutralized solution and to reduce the volume of reactors and other capacitive equipment by 1.5-2 times. By reducing the amount of depreciation and reducing energy costs, the cost of two-water barium chloride is reduced by 1.2 times.

Information sources

1. Pozin M.E. The technology of mineral salts. - P .: Chemistry. - 1970, part 1 - 791.

2. Trutnev G. A., Malakhov A. N., Strigunov F. I., Gitis E. B., Proshin A. F., Shakirov Z. M. A method of producing barium chloride. Copyright certificate No. 652114, publ. 03/15/79. Bulletin of inventions No. 10.

3. Russo G.V., Boldyreva O.M. A method of obtaining crystals of barium chloride dihydrate. Copyright certificate No. 1557104, publ. 04/15/90. Bulletin of inventions No. 14.

Claims (1)

A method of producing a two-water barium chloride by decomposing a barium sulfide melt by a solution of hydrochloric acid, separating the solution from insoluble sludge and separating a two-water barium chloride by cooling a neutral solution, characterized in that the decomposition of barium sulfide melt is carried out with barium chloride hydrochloride obtained by mixing a saturated mother liquor after separation of chloride crystals barium with 40% hydrochloric acid in a ratio that ensures the proportion of hydrochloric acid in the mixture is 10-11%, the proportion of barium chloride is 20-21%.