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Method for co-producing calcium sulphate and magnesium hydrate by ammonia alkali waste liquid and concentrated seawater

A technology of magnesium hydroxide and concentrated seawater, applied in the direction of magnesium hydroxide, calcium/strontium/barium sulfate, etc., can solve problems such as salt pans occupying a large area, achieve comprehensive utilization, inhibit spontaneous nucleation, and high separation efficiency Effect

Active Publication Date: 2013-03-06
TIANJIN SEA WATER DESALINATION & COMPLEX UTILIZATION INST STATE OCEANOGRAPHI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this process is that it needs to occupy a large area of ​​salt fields, which has great limitations for enterprises that do not have the conditions for drying salt, and it is impossible to completely solve the problem of disposal of ammonia-alkali waste liquid

Method used

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  • Method for co-producing calcium sulphate and magnesium hydrate by ammonia alkali waste liquid and concentrated seawater
  • Method for co-producing calcium sulphate and magnesium hydrate by ammonia alkali waste liquid and concentrated seawater

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Take ammonia-alkali waste liquid, place it in a settler for sedimentation, and purify and remove insoluble matter. Pump the supernatant of the settler into the filter for filtration, and analyze the composition of the filtrate: Ca 2+ 0.90mol / L, Na + 0.79mol / L, Cl - 2.59mol / L. Weigh 347g of calcium hydroxide, dissolve it in 8L of purified ammonia-alkali waste liquid, and stir to form a mixed solution. Take 24L concentrated seawater and analyze the composition of concentrated seawater: SO 4 2- 0.094mol / L, Ca 2+ 0.033mol / L, Mg 2+ 0.19mol / L, Cl - 1.68mol / L, K + 0.036mol / L, Na + 2.13mol / L.

[0032] The above-mentioned mixed solution of purified ammonia-alkali waste liquid dissolved in calcium hydroxide and concentrated seawater are continuously added to the crystallization reactor at the same time from the mixed liquid inlet 10 and the concentrated seawater inlet 11 respectively, and the mixed solution of the purified ammonia-alkali waste liquid dissolved in calciu...

Embodiment 2

[0036] Take ammonia-alkali waste liquid, first place it in a settler to settle, and remove insoluble matter. Pump the supernatant of the settler into the filter for filtration, and analyze the composition of the filtrate: Ca 2+ 0.90mol / L, Na + 0.79mol / L, Cl - 2.59mol / L. Weigh 520 g of calcium hydroxide, dissolve it in 6 L of purified ammonia alkali waste liquid, and stir to form a mixed liquid. Take 24L concentrated seawater and analyze the composition of concentrated seawater: SO 4 2- 0.094mol / L, Ca 2+ 0.033mol / L, Mg2+ 0.19mol / L, Cl - 1.68mol / L, K + 0.036mol / L, Na + 2.13mol / L.

[0037] The above-mentioned mixed solution of purified ammonia-alkali waste liquid dissolved in calcium hydroxide and concentrated seawater are continuously added to the crystallization reactor at the same time from the mixed liquid inlet 10 and the concentrated seawater inlet 11 respectively, and the mixed solution of the purified ammonia-alkali waste liquid dissolved in calcium hydroxide is ...

Embodiment 3

[0041] Take ammonia-alkali waste liquid, first place it in a settler to settle, and remove insoluble matter. Pump the supernatant of the settler into the filter for filtration, and analyze the composition of the filtrate: Ca 2+ 0.90mol / L, Na + 0.79mol / L, Cl - 2.59mol / L. Weigh 832g of calcium hydroxide, dissolve it in 10L of purified ammonia alkali waste liquid, and stir to form a mixed solution. Analysis of concentrated seawater composition: SO 4 2- 0.13mol / L), Ca 2+ 0.05mol / L, Mg 2+ 0.3mol / L, Cl - 3.26mol / L, K + 0.064mol / L, Na + 2.78mol / L.

[0042] Take the above-mentioned purified ammonia-alkali waste liquid dissolved calcium hydroxide mixed solution and 30L concentrated seawater and add them continuously to the crystallization reactor at the same time through inlets 10 and 11 respectively, and adjust the inlet of the purified ammonia-alkali waste liquid dissolved calcium hydroxide mixed solution and concentrated seawater. The feed rate is 3.2L / h and 9.5L / h respec...

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Abstract

The invention discloses a method for co-producing calcium sulphate and magnesium hydrate by ammonia alkali waste liquid and concentrated seawater. The method comprises the technical steps of ammonia alkali waste liquid purification, calcium hydroxide dissolving, crystallization reaction, kettle bottom slurry liquid separation washing and overflowing slurry liquid filtering washing. The calcium sulphate is dissolved in the purified ammonia alkali waste liquid, formed mixed solution and the concentrated seawater are respectively and continuously added into a crystallization reactor, the circulation mixing is carried out under the effect of a circulation lifting device arranged in the crystallization reactor, sulfate ions and calcium ions are combined to form large-grain-diameter calcium sulfate crystals to be settled to the bottom of the crystallization reactor, magnesium ions and hydroxyl ions are combined to form magnesium hydrate with smaller grain diameter, and the magnesium hydrate is lifted in the crystallization reactor through the circulation lifting device and overflows from an overflowing opening. The method has the characteristics of simple work procedure, high separation efficiency and the like, and the comprehensive utilization of resources is further realized.

Description

technical field [0001] The invention relates to a method for preparing calcium sulfate and magnesium hydroxide in the field of inorganic chemical industry, in particular to a method for co-producing calcium sulfate and magnesium hydroxide by using a mixed solution of ammonia-alkali waste liquid to dissolve calcium hydroxide and concentrated seawater through crystallization technology. Background technique [0002] my country is a big producer of soda ash, and the total output of soda ash has exceeded 20 million tons. The currently used soda ash production process is mainly the ammonia-soda method. The production process of ammonia-soda soda ash produces a large amount of ammonia-soda waste liquid, and every ton of soda ash produced will discharge 10m 3 ammonia alkali waste liquid. The traditional ammonia-alkali waste liquid treatment method is to discharge the waste liquid into the slag yard of earth-rock dam embankment, natural clarification, natural carbonization, and dis...

Claims

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Application Information

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IPC IPC(8): C01F11/46C01F5/22
Inventor 王俐聪张琦王涛骆碧君王亮武海虹陆永超吴丹黄西平
Owner TIANJIN SEA WATER DESALINATION & COMPLEX UTILIZATION INST STATE OCEANOGRAPHI
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