Method for treating magnesium sulfate and magnesium sulfite wastewater by virtue of lime method

A magnesium sulfite, magnesium sulfate technology, applied in separation methods, chemical instruments and methods, calcium/strontium/barium sulfate and other directions, can solve the problems of high energy consumption and high cost, achieve high separation efficiency, improve product purity, The effect of large separation coefficient of calcium and magnesium

Active Publication Date: 2016-08-17
TIANJIN SEA WATER DESALINATION & COMPLEX UTILIZATION INST STATE OCEANOGRAPHI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Aiming at the problems of high energy consumption and high cost in the current magnesium sulfate and m

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  • Method for treating magnesium sulfate and magnesium sulfite wastewater by virtue of lime method
  • Method for treating magnesium sulfate and magnesium sulfite wastewater by virtue of lime method

Examples

Experimental program
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Example Embodiment

[0037] Example 1:

[0038] After the flue gas desulfurization of the power plant, the waste liquid is placed in a settler to settle to purify and remove insoluble matter. Pump the supernatant liquid of the settler into the filter for filtration, and analyze the composition after aeration treatment: Mg 2+ Content 2.04mol / L, SO 4 2- The content is 2.02mol / L; the lime slurry calcium hydroxide concentration is 1mol / L.

[0039] The above-mentioned purified magnesium sulfate waste liquid and lime slurry are continuously added to the reaction crystallizer from the wastewater inlet 11 and the lime slurry inlet 12 respectively, and the feed amounts of the purified magnesium sulfate waste liquid and lime slurry are adjusted to 2.4m respectively. 3 / h and 4.9m 3 / h. When the feed liquid level in the reaction crystallizer exceeds the upper mouth of the circulating lifting device 6, the circulating lifting device 6 is turned on, and the circulating liquid lifting flow rate of the circulating li...

Example Embodiment

[0041] Example 2:

[0042] Take the magnesium sulfate type underground brine and place it in a settler to purify and remove insoluble matter. Pump the supernatant liquid of the settler into the filter and analyze the composition: Mg 2+ Content 0.21mol / L, SO 4 2- Content 0.16mol / L, Cl - Content 0.14mol / L, Ca 2+ The content is 0.02mol / L; the lime slurry calcium hydroxide concentration is 0.25mol / L.

[0043] The above-mentioned purified magnesium sulfate waste liquid and lime slurry are continuously added to the reaction crystallizer from the wastewater inlet 11 and the lime slurry inlet 12 respectively, and the feed amounts of the purified magnesium sulfate waste liquid and lime slurry are adjusted to 10.2m respectively. 3 / h and 8.0m 3 / h. When the feed liquid level in the reaction crystallizer exceeds the upper mouth of the circulating lifting device 6, the circulating lifting device 6 is turned on, and the circulating liquid lifting flow rate of the circulating lifting device 6 is...

Example Embodiment

[0045] Example 3:

[0046] Wastewater from a factory, main component: Mg 2+ Content 1.23mol / L, SO 3 2- Content 1.02mol / L, SO 4 2- The content is 0.20mol / L; the waste water is placed in a settler to settle, purify and remove insoluble matter. Pump the supernatant liquid of the settler into the filter for filtration, and configure the lime slurry with a calcium hydroxide concentration of 1.6 mol / L.

[0047] The above-mentioned purified magnesium sulfate waste liquid and lime slurry are continuously added to the reaction crystallizer from the waste water inlet 11 and the lime slurry inlet 12 respectively, and the feed amounts of the purified magnesium sulfate waste liquid and lime slurry are adjusted to 10m respectively. 3 / h and 6.8m 3 / h. When the feed liquid level in the reaction crystallizer exceeds the upper opening of the circulating lifting device 6, the circulating lifting device 6 is turned on, and the circulating liquid lifting flow rate of the circulating lifting device 6 i...

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Abstract

The invention discloses a method for treating magnesium sulfate and magnesium sulfite wastewater by virtue of a lime method. Technical steps comprise settling purification, aeration oxidization, reactive crystallization separation, overflow liquid filtering, washing and drying, kettle-bottom slurry washing and separation and filtered stock recycling. Purified and oxidized wastewater and lime slurry are continuously added into a reaction crystallizer respectively, and a reactive crystallization condition is controlled to bond sulfate ions and calcium ions to form and settle calcium sulfate dihydrate crystals with larger particle sizes at the bottom of the reactive crystallizer and bond magnesium ions and hydroxide ions to form magnesium hydroxide with smaller particle sizes to continuously overflow from an overflow opening of the reactive crystallizer. The method has the characteristics of simple procedures, high separation efficiency, low equipment investment and running cost and the like, and can be used for treating magnesium sulfate and magnesium sulfite wastewater in large batches. Reaction products can be used for preparing high-quality magnesium hydroxide and calcium sulfate dihydrate for selling as chemical products; reaction mother liquor can be used as process water instead of fresh water, so that zero emission of magnesium sulfate and magnesium sulfite wastewater can be implemented.

Description

Technical field [0001] The invention relates to wastewater treatment technology, in particular to a method for preparing magnesium hydroxide and calcium sulfate dihydrate by treating magnesium sulfate and magnesium sulfite wastewater by a lime method. Background technique [0002] In recent years, magnesium desulfurization technology has been used more in areas with abundant magnesium sources due to its advantages of high desulfurization efficiency, simple process and lower investment costs, and has achieved the removal of sulfur dioxide in flue gas from coal-fired boilers. Make coal-fired boiler flue gas meet emission standards. At the same time, the desulfurization method produces a large amount of waste water containing desulfurization by-products such as magnesium sulfate and magnesium sulfite. With the country's increasingly strict wastewater discharge and the implementation of the "energy saving and emission reduction" strategy, the treatment and resource reuse of wastewat...

Claims

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Application Information

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IPC IPC(8): C01F5/22C01F11/46B01D9/02
CPCB01D9/00C01F5/22C01F11/46
Inventor 赵旭王涛张琦路绍琰王亮王泽江黄西平
Owner TIANJIN SEA WATER DESALINATION & COMPLEX UTILIZATION INST STATE OCEANOGRAPHI
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