SU1758002A1 - Method of producing concentrated solutions of magnesium sulfate from sea type brine - Google Patents

Abstract

Use: in the processing of natural brines. The method consists in concentrating sea water or brine in the sun to a density of 1270–1290 kg / m3, separating the crystallized sodium chloride and mechanical impurities, and treating the resulting concentrated ammonium sulfate with a suitable solution of ammonium sulfate at a rate of 25–40 g not 100 ml of brine. Then, after isolating the magnesium ammonium shenite crystals, the mixture was stirred for 5 minutes, then settled for 10 minutes. The shenite crystals were separated by filtration, and an equal volume of 0.1 M lime milk was added to the filtrate. The gypsum-magnesia mass formed is filtered, washed with water, mixed with the previously obtained shenite, m. The resulting wet paste is mixed with simultaneous removal of ammonia under reduced pressure. After 2-2.5 hours, the reaction mixture is treated with hot water and filtered to obtain a concentrated solution. magnesium sulfate. 1 tab. (L

Description

The invention relates to the technology of mineral salts, in particular to methods for producing magnesium compounds from natural raw materials, and can be used in natural brine processing plants.

The aim of the invention is to reduce the volume of wastewater.

The method is carried out as follows.

Seawater or brine is concentrated by evaporation in the sun to a density of 1270–1290 kg / m3 and the crystallized sodium chloride and mechanical impurities are separated. The resulting concentrated brine is treated with an aqueous solution of ammonium sulfate at the rate of 25-40 g per 100 ml of brine. After 2 to 3 minutes, the release of magnesium ammonium shenite crystals ((MS) 2304 bNaO) begins. The mixture is stirred for 5 minutes, then set aside for 10 minutes. The chenite crystals are separated by filtration, and an equal volume of 0.1 M milk of lime is added to the filtrate. The resulting gypsum-magnesia mass is filtered off, washed with water and mixed with the previously obtained shenite. The resulting wet paste is mixed while removing ammonia under reduced pressure. After 2-2.54 g, the reaction mixture is treated with hot water and filtered to obtain a concentrated magnesium sulfate solution.

Example 1. A synthetic solution prepared from pure salts and in composition corresponding to the Sivash brine is evaporated before the essolmitis is precipitated. The resulting model solution has

X СЛ 00 О О Ю

a density of 1270 kg / m3 and the following composition1 9.7% MgS04, 13.9% MgCI2, 5.3% NaCI. 2.7% KCI. The total concentration of magnesium ions in the solution is 2.26 g-ion / L.

To 100 ml of the model solution was added 25.2 g (0.18 mol) of ammonium sulfate, dissolved in 50 ml of water. After separating chenite (44.2 g), 120 ml of limestone containing 0.012 mol of Ca (OH) 2 was added to the filtrate. After filtration and washing with water, the gypsum-magnesia mass is combined with chenite crystals and stirred for 2 hours. 100 ml of hot water is added to the reaction mass, heated to boiling and immediately filtered.

The yield of magnesium based on MgS04 7H20 is 69.5%, the content of ions Caf + 0.13%.

Examples 2-4 differ from example 1 only in the amount of ammonium sulphate taken to precipitate chenite. The conditions of the process and the results obtained in these examples are shown in the table.

Example 5. 20 liters of sea water are evaporated in the sun to a volume of 130 ml. During the evaporation process, the solution is periodically filtered from drop-down & precipitate of crystals consisting mainly of sodium chloride. A total of 270 g of salt is obtained.

To the resulting brine with a density of 1290 kg / m is added 40 g of ammonium sulfate dissolved in 50 ml of water. After filtration, 64.5 g of chenite are obtained. Further processing was carried out under the conditions of Example 1. The yield of magnesium was 72.1, the content of Ca ions was 0.085%.

From the table it follows that with a shortage of precipitator compared with the claimed

outside the yield of magnesium sulfate is significantly reduced.

The application of the proposed method allows to reduce the amount of wastewater per 1 t from 170 m according to the known

method up to 2.5 m3.

Claims (1)

Claims of Invention A method for producing concentrated solutions of magnesium sulfate from sea-type brines, including gypsum-magnesia mass by interaction with lime milk, processing the gypsum-magnesia mass obtained with a reagent and subsequent filtration of the reaction mixture to obtain the target product, characterized in that, in order to reduce the volume of wastewater, the initial brine is pre-concentrated by natural evaporation to a density of 1270 - 1290 kg / m3, the precipitate is separated, one stripped brine is treated with raster ammonium sulfate in an amount of 25-40 g per 100 ml of brine The resulting shenite is filtered off and a gypsum-magnesia mass is obtained from the filtrate, which is treated with the obtained shenite, and the reaction mixture is mixed with water before filtration and brought to a boil; gypsum-magnesia mass is used with concentration of 0.1 M. Compiled by S. Yakunin Editor Z. KhodakovaTehred M.MorgentalKorrektor S. Lisin Order 2969 Circulation: Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, 4/5 Raushsk nab. Production and publishing combine Patent, Uzhgorod. 101 Gagarin St.