Method for eliminating calcium sulphate with bittern

A technology of calcium sulfate and brine, applied in chemical instruments and methods, water/sewage treatment, water/sludge/sewage treatment, etc., can solve problems such as ecological pollution and destruction of marine ecological environment, save energy and increase product output and quality, and the effect of improving resource utilization

Inactive Publication Date: 2008-05-07
ENG TECH INST CO LTD OF CNSIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, China is vigorously developing seawater desalination projects to obtain fresh water from the sea. However, the concentration of concentrated seawater discharged after seawater desalination is generally above 5°Be', and the seawater needs to be acidified and various chemical reagents are added in the desalination process to remove Biological and various harmful impurities, if the concentrated seawater is discharged directly, it may destroy the ecological environment of the ocean and cause serious ecological pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The Bohai Bay brine with 5°Be’ is selected, and the composition of the brine is as follows:

[0028] NaCl: 40.00g / l

[0029] KCl: 1.04g / l

[0030] MgCl 2 : 5.15g / l

[0031] MgSO 4 : 3.53g / l

[0032] CaSO 4 : 1.97g / l

[0033] Density: 1039g / l

[0034] The composition of industrial raw salt is as follows:

[0035] NaCl: 96%

[0036] Ca 2+ : 0.2%

[0037] 5O 4 2- : 0.58%

[0038] After adding 116g / l of industrial crude salt, the concentration of brine reaches 17°Be', and the precipitation of calcium sulfate is 1.12g / l. The composition of brine is as follows:

[0039] NaCl: 156.73g / l

[0040] KCl: 1.04g / l

[0041] MgCl 2 : 5.04g / l

[0042] MgSO 4 : 3.40g / l

[0043] CaSO 4 : 1.94g / l

[0044] Density: 1149g / l

[0045] Most of the calcium sulfate is removed from the obtained brine, and the brine can directly produce high-quality products such as magnesium hydroxide and magnesium carbonate. In this example, most of the calcium sulfate in the brine is rem...

Embodiment 2

[0047] The Bohai Bay brine with 13°Be’ is selected, and the composition of the brine is as follows:

[0048] NaCl: 107.62g / l

[0049] KCl: 2.76g / l

[0050] MgCl 2 : 17.19g / l

[0051] MgSO 4 : 10.40g / l

[0052] CaSO 4 : 5.60g / l

[0053] Density: 1101g / l

[0054] The composition of industrial raw salt is as follows:

[0055] NaCl: 96%

[0056] Ca 2+ : 0.2%

[0057] SO 42 -: 0.58%

[0058] After adding 49g / l of industrial crude salt, the concentration of the brine reached 17°Be', and the precipitation of calcium sulfate was 3.66g / l. The composition of the brine is as follows:

[0059] NaCl: 156.73g / l

[0060] KCl: 2.80g / l

[0061] MgCl 2 : 17.50g / l

[0062] MgSO 4 : 11.50g / l

[0063] CaSO 4 : 1.94g / l

[0064] Density: 1147g / l

[0065] In this example, the large calcium sulfate dissolved in the brine is removed to be used for refining the brine to produce magnesium series products. When the brine enters the vacuum salt making system, the equipment is not eas...

Embodiment 3

[0067] The Bohai Bay brine with 13°Be’ is selected, and the composition of the brine is as follows:

[0068] NaCl: 107.62g / l

[0069] KCl: 2.76g / l

[0070] MgCl 2 : 17.19g / l

[0071] MgSO 4 : 10.40g / l

[0072] CaSO 4 : 5.60g / l

[0073] Density: 1101g / l

[0074] The composition of industrial raw salt is as follows:

[0075] NaCl: 96%

[0076] Ca 2+ : 0.2%

[0077] SO 4 2- : 0.58%

[0078] After adding 124g / l of industrial crude salt, the concentration of the brine reaches 25°Be', and the precipitation of calcium sulfate is 3.72g / l. The composition of the brine is as follows:

[0079] NaCl: 231.50g / l

[0080] KCl: 2.80g / l

[0081] MgCl 2 : 17.70g / l

[0082] MgSO 4 : 10.80g / l

[0083] CaSO 4 : 4.23g / l

[0084] Density: 1215g / l

[0085] This example can remove most of the calcium sulfate dissolved in the brine, and the brine directly enters the vacuum salt making evaporation system to reduce energy consumption; the separated calcium sulfate can be used to pr...

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PUM

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Abstract

The invention provides seawater processing technology, in particular to a method of removing calcium sulphate by use of brine. 5 to 13 degrees Be brine is added with industrial crude salt to make the brine concentration to 17 to 25 degrees Be and dissolve the calcium sulphate. According to the rule of brine dissolving salt and the salting-out theory as well as the common ion effect theory, the composition of the(5 to 13 degrees Be) brine is changed by adding the industrial crude salt to increase the sodium chloride content in the brine so as to increase the brine concentration up to 17 to 25 degrees Be, thereby reducing the solubility of the calcium sulphate and dissolving most of the calcium sulphate; besides, the dissolved brine can be directly used for producing the vacuum refined salt.

Description

technical field [0001] The invention relates to seawater treatment technology, in particular to a method for removing calcium sulfate from brine. Background technique [0002] Seawater contains Na + 、K + , Mg 2+ , Ca 2+ , Cl - , SO 4 2- In addition to these constant ions, it also contains dozens of other trace elements. Therefore, since ancient times, humans have developed the ocean and carried out comprehensive development and utilization of seawater resources. In particular, the use of seawater to make salt has a long history. Traditionally, the production process of comprehensive utilization of seawater is: seawater or concentrated seawater (with a concentration of 3-6°Be') is discharged into the salt pan, and then concentrated to 13° by natural evaporation step by step. About Be', then evaporate to a concentration of about 18°Be', during this period a large amount of calcium sulfate in the brine precipitates on the salt pool plate, and when the brine is saturated ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/58
Inventor 靳志玲李树生吴宗生
Owner ENG TECH INST CO LTD OF CNSIC
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