SU874625A1 - Method of producing glauber's salt - Google Patents

Description

(54) METHOD FOR GETTING GLOBE

one

The invention relates to chemical technology, in particular to methods for the preparation of the Glauber's salt and sulphate-containing solutions, and can be used in the processing of natural brines.

The basin method of obtaining mirabilite and glauber’s salt is known, which consists in cooling the sulphate-containing brine at the expense of natural cold, isolating mirabilite, washing it and drying it in natural conditions.

The main drawbacks of the basin method are the dependence of the process on the natural conditions and the high content of mechanical and chemical impurities due to the lack of the possibility of their removal, as well as the duration of the process of obtaining the glauber salt.

Also known is the factory method of obtaining the Glauber's salt from natural sulphate-containing brines, which consists in cooling the brines to a temperature of O minus 1 ° C, separating the crystals of mirabilite, separating the resulting suspension, washing the precipitate and drying it with air on 2J filters. SSI1I

The disadvantage of this method is that mirabilite is a raw material for the production of the Glauber's salt, which is an intermediate product of arbitrariness, and the drying of the Glauber's salt from hygroscopic moisture on the filters is long in time.

The closest to the proposed technical essence and the achievable effect is the method of obtaining the Glauber's salt from burners, sodium sulfate brine by gradual cooling to a temperature below 32 C. The precipitated crystals of mirabilite are separated, dried and get Glauber salt t3.

The main disadvantage of the method is the long drying time of the Glauber's salt from hygroscopic moisture. ,

The purpose of the invention is to intensify the process by reducing the drying time of the Glauber's salt precipitate, increasing the content of the main substance and reducing energy consumption.

This goal is achieved by adding sodium sulfate to the initial solution in an amount of 2-3.2 wt.% Of the initial solution.

While cooling the solution lead to 17.9-32 ,.

The method is carried out as follows.

in the waste liquor formed in the process of obtaining sodium sulfate from sulfate brines, having a temperature of EO-CQ and containing,%: Na2SO424.26, NaCB 2-3, MgCC / z 3-4 / dry sodium sulfate in the amount of 2- 3.2 wt.% Solution.

After that, in the mold waste liquor is cooled to 17.932,. When this occurs, mirabilite crystallizes. The crystallization temperature depends on the fluctuations of the chemical composition of the waste liquor. The lower limit of the cooling temperature corresponds to compositions with low concentrations of MgCeg, the upper one with elevated levels. Deeper cooling will lead to increased moisture content of the product. The yield of mirabilite from waste liquor is 240250 kg per 1000 kg of solution.

The resulting suspension is divided and washed with fresh water in a centrifuge or filter, while the hygroscopic moisture content of the sediment varies from 7.5 to 12.5%.

Sodium sulfate, introduced into the liquor in a stoichiometric ratio, with free water binds it and goes into mirabilite. This makes it possible to significantly reduce or eliminate the stage of drying the precipitate of Glauber's salt with air. The limits of the amount of sodium sulfate added are due to variations in the composition of the feedstock.

Sodium sulfate, depending on the specific conditions, may be added to

liquor in the form of a powder, and in the form of its suspension, obtained by vacuum evaporation of liquor. The method allows to significantly intensify the process of production of Glauber's salt while maintaining the quality of the finished product.

Example. In 1000 g of a saturated sulphate solution of the composition, wt.% 1 Na2S04 25.33; NaC € 3,5; MgCt 2.57; N-68.6, having a temperature

26 g of sodium sulfate are added. Thereafter, the solution is cooled with constant stirring to a temperature D at which mirabilite crystallizes. The resulting suspension is filtered and washed with fresh water. After filtration and washing, the precipitate of the Glauber's salt is analyzed for chemical composition.

In parallel, laboratory experiments were carried out to obtain the Glauber's salt from waste liquor without introducing sodium sulfate into the solution, as well as at a dosage of sodium sulfate in the amount of 2 and 3.2 weights,% solution.

The test results show that the proposed method for the production of the Glauber's salt makes it possible to almost completely refuse to dry the Glauber's salt precipitate with air.

The total time required for filtering the slurry and washing the precipitate is l 10 minutes. The data on the quality of the target product are presented in the table, where in column 5 of EE the requirements for medical glauber salt are given in accordance with article No. 439 of the USSR State Pharmacopoeia, X edition.

crystallization, С

Mirabi0 yield, 242 0.24 0.246 0.250 lt t / t

25

25

The amount of sodium sulfate, weight%

The chemical composition of glauber's salt

Claims (3)

43.01 47.715 43.77 37.78 56.9 52.2 56.125 62.12 As can be seen from the table, only when introduced into the initial solution of sodium sulfate, spreobob produces a glass salt that meets the requirements (monograph No. 439 Medical ska glauber salt. Formula of the invention 1. A method of obtaining the Glauber's salt from sulphate-chloride brines by cooling them to the crystallization temperature of mirabilite, followed by separating the resulting suspension and washing the resulting precipitate, characterized 874625, 6 Table continuation 3.2 2.6 0.09 0.085 0.1 0.1 0.1 52 - 57 In order to intensify the process, increase the content of the basic substance and reduce energy consumption, sodium sulfate is introduced into the initial solution in an amount of 2-3 / 2 wt.% Of the initial solution. 2. The method according to claim 1, about t l and h ayushch and I so that the cooling solution is carried out to a temperature of 17.9-32.5 ° C. Sources of information taken into account during the examination 1.Gorbanev AI, Nikolina V.Ya. Sodium sulfate. M., 1954, p. 44-49. 2. Pozin M.E. Mineral salt technology. V. 1, 1974-, p. 108-114. 3. The patent of France 2210571, cl. C 01 D 5/00, 1974 (prototype).