Calcium hardness reducing method of recycle water of non-ferrous metallurgical acid waste water

A technology for acidic wastewater and reuse water, applied in the direction of water softening, etc., can solve the problems of equipment scaling, reduce calcium content in reuse water, etc., and achieve the effect of easy control of pH value and simple treatment method.

Inactive Publication Date: 2017-08-04
YANTAI UNIV
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Problems solved by technology

[0007] In order to solve the deficiencies of the prior art, the purpose of the present invention is to address the defects of the existing nonferrous metallurgical acid wastewater recovery and treatment methods, especially the high calcium content in the reused water after the neutralization and precipitation method, resulting in serious scaling of the equipment. problem, propose a method to reduce the calcium hardness of acid wastewater reuse water, so as to effectively reduce the calcium content of reuse water

Method used

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  • Calcium hardness reducing method of recycle water of non-ferrous metallurgical acid waste water

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Embodiment 1

[0044] The acid wastewater to be treated was taken from a factory in Yantai. Among them, the content of arsenic ions is 5000mg / L, the content of copper ions is 300mg / L, the content of lead ions is 20mg / L, the content of cadmium ions is 20mg / L, the content of zinc ions is 700mg / L, and the content of iron ions is 1600mg / L.

[0045] Wastewater and milk of lime are added to the neutralization sedimentation tank for stirring reaction. This process produces a large amount of precipitates, mainly calcium carbonate, calcium sulfate and heavy metal hydroxides. After this reaction step, most of the heavy metal ions of polluted acid are precipitated. .

[0046] The reacted mixture is transported to the conical settling tank for solid-liquid separation. The calcium hardness of the supernatant is 536mg / L, mainly containing calcium sulfate, and the precipitated residue containing heavy metals is sent to the plate and frame filter press for pressure filtration, and the filtrate is returned t...

Embodiment 2

[0051] Wastewater to be treated is also taken from the plant. Among them, the content of arsenic ions is 5500mg / L, the content of copper ions is 280mg / L, the content of lead ions is 15mg / L, the content of cadmium ions is 15mg / L, the content of zinc ions is 675mg / L, and the content of iron ions is 1700mg / L.

[0052] The treatment steps are the same as in Example 1. After neutralization and precipitation, the calcium ion content of the clear liquid is 320 mg / L, and after the reaction of carbon dioxide and sodium hydroxide, the calcium ion content of the recycled water is 31 mg / L.

[0053] Through the above-mentioned embodiment, the reaction of carbon dioxide and calcium ions reduces the calcium hardness, and fully meets the industrial production calcium ion content standard (≤200mg / L).

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Abstract

The invention provides a calcium hardness reducing method of recycle water of non-ferrous metallurgical acid waste water. The method includes steps of neutralizing and settling acid waste water by lime milk, and then adjusting pH value of clear liquid firstly; charging carbon dioxide and calcium ion to react and generate calcium carbonate sediment, removing calcium ion; in order to further reduce the calcium content in the recycle water, continuing to charge carbon dioxide, and reversely dissolving the calcium carbonate sediment under the function of hydrogen ion to generate calcium bicarbonate; at the moment, adding sodium hydroxide in the solution, and rapidly generating a lot of sediments again; using the clear liquid after filtering for production. After treatment by the calcium hardness reducing method, the content of calcium ion can be reduced to 20 mg / L-35 mg / L, and the standard of industrial recycle water is completely reached. The method is simple in technique, the pH value is easy to control, the calcium hardness of the recycle water is effectively reduced, the cost is saved, and the method is economic and environment-friendly.

Description

technical field [0001] The invention relates to a treatment technology for nonferrous metallurgical acidic wastewater, in particular to a method and a treatment system for reducing calcium hardness of recycled water in nonferrous metallurgical acidic wastewater. Background technique [0002] The non-ferrous metallurgical industry is a highly polluting industry, which is characterized by typical heavy metal pollution, and various degrees of wastewater will be generated in various links such as beneficiation and smelting. Wastewater has complex components, high heavy metal content, high turbidity, high acidity, and large flow. Toxic heavy metals contained in wastewater include arsenic, cadmium, mercury, fluorine, chlorine, etc. At present, domestic and foreign non-ferrous metal industry wastewater treatment technologies mainly include neutralization precipitation method, sulfide precipitation method, ion exchange method, adsorption method, membrane separation method and biolo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F5/02
CPCC02F5/02
Inventor 李维平南君芳尚军刚李天文王全龙孙慧梅
Owner YANTAI UNIV
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