Method for treating magnesium sulfate wastewater by lime-base process

A technology of magnesium sulfate and lime method, applied in water/sewage treatment, chemical instruments and methods, multi-stage water/sewage treatment, etc., can solve the problems of complex process, environmental pollution, high operation requirements, etc., and achieve simple equipment and low operating cost Low, energy-saving effect

Inactive Publication Date: 2017-12-08
淄博美盛化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this process is that the process is complicated, the operation requirements are high, and the use of organic inhibitors and collectors will also cause pollution to the environment.

Method used

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  • Method for treating magnesium sulfate wastewater by lime-base process
  • Method for treating magnesium sulfate wastewater by lime-base process

Examples

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Effect test

Embodiment 1

[0022] A method for treating magnesium sulfate wastewater by lime method, the steps are as follows:

[0023] Step 1: Digest the unslaked lime with a lime machine to obtain milk of lime;

[0024] Step 2: The magnesium sulfate wastewater containing 11.2% magnesium sulfate content from the boiler flue gas desulfurization system is 3 The flow rate of / h is added to the reactor, the reaction temperature is controlled to be 20°C, and then 5% milk of lime prepared in step 1 is added for reaction to obtain a slurry containing magnesium hydroxide and calcium sulfate dihydrate with a pH value of 9. material;

[0025] Step 3: Put the slurry that has been reacted in step 2 into the buffer of the equipment or directly pump it into the hydrocyclone for separation. The pressure at the inlet of the hydrocyclone is controlled at 0.12MPa, and the ratio of the discharge from the overflow port to the underflow port is as follows: The volume flow rate is controlled at 5:1. Most of the magnesium ...

Embodiment 2

[0031] A method for treating magnesium sulfate wastewater by lime method, the steps are as follows:

[0032] Step 1: Digest the unslaked lime with a lime machine to obtain milk of lime with a concentration of 15%;

[0033] Step 2: The magnesium sulfate wastewater containing 13.6% magnesium sulfate from the boiler flue gas desulfurization system is 3 Add the flow rate of / h in the reactor, control the reaction temperature to be 80°C, then add the milk of lime prepared in step 1 to react, and obtain a slurry containing magnesium hydroxide and calcium sulfate dihydrate with a pH value of 11.5;

[0034] Step 3: Put the slurry that has been reacted in step 2 into the buffer of the equipment or directly pump it into the hydrocyclone for separation. The pressure at the inlet of the hydrocyclone is controlled at 0.35MPa, and the ratio of the discharge from the overflow port to the underflow port is as follows: The volume flow rate is controlled at 10:1. Most of the magnesium hydroxid...

Embodiment 3

[0040] A method for treating magnesium sulfate wastewater by lime method, the steps are as follows:

[0041] Step 1: Digest the unslaked lime with a lime machine to obtain milk of lime;

[0042] Step 2: The magnesium sulfate wastewater containing 12.5% ​​magnesium sulfate from the boiler flue gas desulfurization system is 3 Add the flow rate of / h into the reactor, control the reaction temperature to be 40°C, then add 10% milk of lime prepared in step 1 to react, and obtain a slurry containing magnesium hydroxide and calcium sulfate dihydrate with a pH value of 9.5 material;

[0043] Step 3: Put the slurry that has been reacted in step 2 into the buffer of the equipment or directly pump it into the hydrocyclone for separation. The pressure at the inlet of the hydrocyclone is controlled at 0.25MPa, and the ratio of the discharge from the overflow port to the underflow port is as follows: The volume flow rate is controlled at 7:1. Most of the magnesium hydroxide comes out of the...

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Abstract

The invention discloses a method for treating magnesium sulfate wastewater by a lime-base process and relates to the field of wastewater treatment. The method comprises the following steps: preparing lime milk into specified concentration, and reacting the lime milk with the magnesium sulfate wastewater under certain conditions; separating a reacted mixture of dihydrate calcium sulfate and magnesium hydroxide by a hydrocyclone; enabling the magnesium hydroxide to be effectively separated from the dihydrate calcium sulfate by two-stage separation; enabling the magnesium hydroxide to return to a desulfurization system for continuously desulfurizing; filtering and drying the dihydrate calcium sulfate to obtain a calcium sulfate product for selling. According to the whole treatment process, the difficult problem of the treatment of the magnesium sulfate wastewater generated by magnesium desulfurization can be thoroughly solved by only supplementing a small amount of primary water and preventing wastewater discharge. The method disclosed by the invention has the beneficial effects that compared with a distillation method, the method has the advantages that the problems of equipment scaling and long operation period are solved; in addition, the equipment is simple and less in investment, so that more energy is saved; compared with a flotation method, the process has the advantages that no various organic auxiliary materials are added in the process, so that the process is more environmentally friendly and lower in operation cost.

Description

technical field [0001] The invention mainly relates to the field of waste water treatment, in particular to a method for treating magnesium sulfate waste water by lime method. Background technique [0002] Magnesium desulfurization is a method of using magnesium compounds (commonly used as magnesium oxide and magnesium hydroxide) to neutralize sulfur dioxide in the flue gas of coal-fired boilers, and then undergo air oxidation to form a magnesium sulfate solution. This method has the advantages of high desulfurization efficiency and small equipment investment, so it is widely used. The main component of the mother liquor after desulfurization is magnesium sulfate. The direct discharge of high-concentration magnesium sulfate wastewater has a great impact on soil and water; discharge into the sewage treatment system will kill the bacteria in the activated sludge. [0003] At present, the mainstream treatment method for magnesium sulfate wastewater is distillation, that is, th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C01F11/46C02F101/20C02F103/18
CPCC01F11/46C02F1/38C02F1/5245C02F1/529C02F2101/20C02F2103/18
Inventor 刘铎张世洁李乐成
Owner 淄博美盛化工有限公司
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