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Method for preparing sodium chloride and magnesium sulphate heptahydrate with brine

A technology of magnesium sulfate heptahydrate and sodium chloride, which is applied in the field of salt production, can solve the problems of large loss of magnesium sulfate, and achieve the effect of simple equipment and simple process

Inactive Publication Date: 2009-01-14
TIANJIN UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The milk of magnesia obtained after the separation of the mixed salt slurry is mainly composed of magnesium sulfate, but contains fine particles of sodium chloride and evaporated mother liquor, which is directly filtered, and then the mother liquor in the milk of magnesia is topped off with water, but because magnesium sulfate is easy to dissolve Great loss of magnesium sulfate

Method used

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  • Method for preparing sodium chloride and magnesium sulphate heptahydrate with brine

Examples

Experimental program
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Effect test

Embodiment 1

[0025] Take 1000ml potassium-containing brine, the composition concentration KCl: 15.0g / l, MgCl 2 : 81.0g / l, MgSO 4 : 93.0g / l, NaCl: 183.0g / l, H 2 O: 890.0g / l, of which SO 4 2- :Na + Molar ratio = 0.25, SO 4 2- : Mg 2+ Molar ratio of 0.48, heating with an electric heating mantle in a three-necked flask, connecting the three-necked flask to a vacuum pump, and controlling the pressure to make the feed liquid boil and evaporate at 55°C, and evaporate 395g of water. At this time, the liquid phase SO 4 2- :Na + The molar ratio is about 1.8, solid-liquid separation is carried out, the solid phase is washed with a saturated aqueous sodium chloride solution, and after drying, 153g of sodium chloride is obtained with a purity of 99.5%. Add 80g of water to the salt-making mother liquor, pre-cool it to 30°C, and add it to the crystallized In the liquid crystallizer (the crystallization liquid is a saturated solution of magnesium sulfate), the temperature of the crystallizer is -...

Embodiment 2

[0027] Take 1000ml of intercrystalline brine from a certain salt lake, the concentration of which is MgCl 2 : 120.0g / l, MgSO 4 : 118.0g / l, NaCl: 140g / l, H 2 O: 818.0g / l, of which SO 4 2- :Na + Molar ratio = 0.41, SO 4 2- :Mg 2+Molar ratio=0.44, heated with an electric heating mantle in a three-necked flask, the three-necked flask was connected to a vacuum pump, and the feed liquid was boiled and evaporated at 60°C by controlling the pressure, and 218.6g of water was evaporated, and the SO in the liquid phase 4 2- :Na + The mol ratio is 1.77, carry out solid-liquid separation, solid phase is washed with saturated sodium chloride aqueous solution, obtains 55g sodium chloride after drying, and purity is at 99.5%; In the crystallizer of the crystallization solution (the crystallization solution is a saturated solution of magnesium sulfate), after fully crystallizing, the solid phase is separated, and the solid phase is added to a saturated solution of magnesium sulfate at...

Embodiment 3

[0029] Take 1000g of seawater to make salt flat brine and dry saturated brine, the composition concentration is Ca 2+ : 0.038%, Mg 2+ : 2.599%, K + : 0.711%, Na + : 7.86%, Cl - : 17.2%, SO 2- 4 : 4.116%, H 2 O: 67.6%, of which SO 4 2- :Na + Molar ratio = 0.127, SO 4 2- : Mg 2+ Molar ratio = 0.40, heating with an electric heating mantle in a three-necked flask, connected to a vacuum pump, and controlling the pressure to make the feed liquid boil and evaporate at 60°C, evaporate 380.g of water, and the SO in the liquid phase 4 2- :Na + Molar ratio 2.05, carry out solid-liquid separation, solid phase is washed with saturated sodium chloride aqueous solution, obtains 170g sodium chloride after drying, and purity is at 99.5%; In the crystallizer (the crystallization liquid is a saturated solution of magnesium sulfate), after fully crystallizing, separate the obtained solid phase, add magnesium sulfate heptahydrate recrystallization mother liquor, and make a saturated ...

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Abstract

The invention discloses a method for using brine to produce sodium chloride and heptahydrate magnesium sulfate, comprising the steps that: (1) brine is taken as a raw material, the molar ratio of SO4<2->:Mg<2+> in the brine is 0.1-0.8, and the molar ratio of SO4<2->:Na<+> is 0.025-1; and the pressure is decreased for boiling evaporation, the pressure is controlled to make the boiling temperature be 75 DEG C to 50 DEG C after the evaporation, and the molar ratio of SO4<2>:Na<+> in the solution is 0.4-2.5; (2) solid-liquid separation is implemented, and the solid phase is washed with saturated sodium chloride aqueous solution and is then dried for obtaining the sodium chloride; (3) a mother liquid of salt production is added with water to prepare a mixture; (4) the mixture is cooled and guided into a crystallizer, then crystals are separated out; and (5) solid-liquid separation is carried out for obtaining a crude product having a solid phase of heptahydrate magnesium sulfate. The method has advantages of simple equipment, simple process, complete separation of sodium chloride, high purity and yield of heptahydrate magnesium sulfate, having no miscellaneous salt removing link in the process, and realizable joint production of sodium chloride and heptahydrate magnesium sulfate.

Description

technical field [0001] The invention relates to the field of salt production, in particular to a method for producing sodium chloride and magnesium sulfate heptahydrate from brine. Background technique [0002] Brine salt is currently widely used to make salt by beach-drying evaporation, or beach-drying saturated brine to make salt by vacuum evaporation. The salt-making mother liquor of the existing salt-making method is either discharged or comprehensively utilized by traditional methods. The way of using discharge is not friendly to the environment. The traditional comprehensive utilization method is centered on the production of potassium chloride by adding brine. The main products are potassium chloride, magnesium chloride (halogen flakes, halogen powder), sodium sulfate, bromine, etc. The salt making mother liquor is mixed with the bromine extracting mother liquor with magnesium chloride as the main component so that the concentration ratio of magnesium sulfate and ma...

Claims

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Application Information

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IPC IPC(8): C01D3/08C01F5/40
Inventor 周桓葛金扬
Owner TIANJIN UNIVERSITY OF SCIENCE AND TECHNOLOGY
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