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Process for producing magnesium sulfate heptahydrate by mother liquor obtained after mirabilite freezing

A technology of magnesium sulfate heptahydrate and mother liquor, applied in the direction of heating water/sewage treatment, etc., can solve the problems of underutilization of magnesium, waste of resources, etc., and achieve the effect of large-scale industrial production, saving consumption, and continuous and stable operation

Inactive Publication Date: 2013-11-27
CHANGSHA DESIGN & RES INST OF CHEM IND MIN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] But in the prior art, there is no industrial technology for producing magnesium sulfate heptahydrate with the mother liquor after freezing nitrate, and the magnesium in the mother liquor has not been fully utilized, resulting in a waste of resources

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] This embodiment includes the following steps:

[0028] (1) One-stage preheating: 4-stage series connection of 40°C brine clearing solution, and 11.5 tons / hour of mother liquor after frozen nitration at -3°C (mother liquor contains: 3.7wt% sodium sulfate, 18.1wt% sulfuric acid Magnesium, 0.3 wt% sodium chloride), preheated to 28 ° C;

[0029] (2) Second-stage preheating: use steam to condense water in 3 stages in series, and preheat the mother liquor after freezing and nitrating at 28°C obtained in step (1) to 55°C;

[0030] (3) Three-stage preheating: use the evaporated secondary steam to divide into three stages, and preheat the frozen mother liquor obtained in step (2) at 55°C to 110°C;

[0031](4) Multi-effect forced circulation evaporation: send the frozen mother liquor obtained in step (3) at 110°C to the first-effect evaporation tank of the four-effect forced circulation evaporation device, and carry out four-effect vacuum evaporation according to the downstream ...

Embodiment 2

[0036] This embodiment includes the following steps:

[0037] (1) One-stage preheating: use 38°C clear solution of bittern in series in 3 stages, and 4.6 tons / hour of mother liquor after freezing nitrate at -2°C (mother liquor contains: 3.5wt% sodium sulfate, 19.0wt% sulfuric acid Magnesium, 0.2wt% sodium chloride) preheating is heated up to 27 ℃;

[0038] (2) Two-stage preheating: use steam to condense water in two stages in series, and preheat the mother liquor after freezing and nitrating at 27°C obtained in step (1) to 52°C;

[0039] (3) Three-stage preheating: use the evaporated secondary steam to divide into three stages, and preheat the 52°C frozen mother liquor obtained in step (2) to 106°C;

[0040] (4) Multi-effect forced circulation evaporation: send the mother liquor obtained in step (3) after freezing nitrate at 106°C to the first-effect evaporation tank of the four-effect forced circulation evaporation device, and carry out four-effect vacuum evaporation accordi...

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Abstract

The invention relates to a process for producing magnesium sulfate heptahydrate by mother liquor obtained after mirabilite freezing, which includes the following steps: (1) first-stage preheating; (2) second-stage preheating; (3) third-stage preheating; (4) multiple-effect forced circulating evaporation; (5) vacuum crystallization; (6) centrifugal separation of slurry; and (7) drying of wet feeds. The invention has the advantages that the process flow is short, the anti-blockage effect is excellent and the energy consumption is low.

Description

technical field [0001] The present invention relates to a kind of technique of producing magnesium sulfate heptahydrate, especially relate to a kind of technique of producing magnesium sulfate heptahydrate from mother liquor after freezing nitrate. Background technique [0002] The production methods of existing industrial grade and fertilizer grade magnesium sulfate heptahydrate have the following 8 kinds: [0003] 1. Sulfuric acid method [0004] Magnesium oxide, magnesium hydroxide or magnesium carbonate react with sulfuric acid to generate magnesium sulfate, the reaction formula is as follows: MgO+H 2 SO 4 +6H 2 O=MgSO 4 ??7H 2 O Mg(OH) 2 +H 2 SO 4 +5H 2 O=MgSO 4 ??7H 2 O MgCO 3 +H 2 SO 4 +6H 2 O=MgSO 4 ??7H 2 O+CO 2 ↑ Taking magnesium oxide as an example, first measure sulfuric acid and magnesium oxide-containing ores (such as dolomite, magnesite, serpentine) or calcined powder in proportion, and add water or washing water and mother liquor to the neut...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/04
Inventor 申军戴斌联宋志青张俊华
Owner CHANGSHA DESIGN & RES INST OF CHEM IND MIN