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Processing and recycling method of waste water discharged from stainless steel pickling process

A technology for pickling wastewater and stainless steel, applied in the field of environmental engineering, can solve the problems of serious secondary pollution, difficult industrial promotion, high processing cost, and achieve the effect of small secondary pollution

Inactive Publication Date: 2011-09-21
HAIYUAN ENVIRONMENTAL SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional treatment methods mainly include chemical precipitation method, oxidation-reduction method, etc., that is, the metal ions in the wastewater are removed by precipitation by adding flocculant or lye. This method has the advantages of low investment and simple operation, but there are also problems of general treatment effect, Large amount of wastewater discharge, serious secondary pollution and other problems
In recent years, various new technologies such as adsorption method, electrochemical reduction method and membrane treatment method have been researched, but there are generally problems such as large investment and high treatment cost, which are difficult to promote in industry

Method used

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  • Processing and recycling method of waste water discharged from stainless steel pickling process

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Experimental program
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Effect test

Embodiment 1

[0021] 1) stainless steel pickling waste water, the water volume is 1000m 3 / d, the water quality is as follows: pH is 1.2, COD Cr 145mg / L, total chromium 420mg / L, total iron 750mg / L, Ni 2+ is 300mg / L, F- is 650mg / L, SS is 160mg / L, the wastewater is pumped into the regulating tank for water quality and water homogenization treatment, and the hydraulic retention time is 2h;

[0022] 2) Pump the effluent from the adjustment tank into the primary reaction tank, adjust the pH to 6.5 by adding lime milk, and add calcium chloride to make most of the fluoride ions in the wastewater react to form CaF 2 , and then add polyacrylamide with a weight percentage of 0.2g / L for flocculation, and the hydraulic retention time of the reaction tank is 0.5h;

[0023] 3) Pump the effluent from the primary reaction tank into the primary sedimentation tank, the hydraulic retention time is 1h, and pump the settled sludge into the sludge thickening tank;

[0024] 4) Pump the effluent from the primar...

Embodiment 2

[0032] 1) stainless steel pickling waste water, the water volume is 800m 3 / d, the water quality is as follows: pH is 1.5, COD Cr 126mg / L, total chromium 362mg / L, total iron 580mg / L, Ni 2+ is 244mg / L, F- is 765mg / L, SS is 186mg / L, the wastewater is pumped into the regulating tank for water quality and water homogenization treatment, and the hydraulic retention time is 2h;

[0033] 2) Pump the effluent from the adjustment tank into the primary reaction tank, adjust the pH to 6.5 by adding lime milk, and add calcium chloride to make most of the fluoride ions in the wastewater react to form CaF 2 , and then add polyacrylamide with a weight percentage of 0.2g / L for flocculation, and the hydraulic retention time of the reaction tank is 0.7h;

[0034] 3) Pump the effluent from the primary reaction tank into the primary sedimentation tank, the hydraulic retention time is 1.5h, and pump the settled sludge into the sludge thickening tank;

[0035] 4) Pump the effluent from the prima...

Embodiment 3

[0043] 1) stainless steel pickling waste water, the water volume is 640m 3 / d, the water quality is as follows: pH is 1.8, COD Cr 164mg / L, total chromium 372mg / L, total iron 850mg / L, Ni 2+is 350mg / L, F- is 850mg / L, SS is 196mg / L, the wastewater is pumped into the regulating tank for water quality and water homogenization treatment, and the hydraulic retention time is 2h;

[0044] 2) Pump the effluent from the adjustment tank into the primary reaction tank, adjust the pH to 6.5 by adding lime milk, and add calcium chloride to make most of the fluoride ions in the wastewater react to form CaF 2 , and then add polyacrylamide with a weight percentage of 0.2g / L for flocculation, and the hydraulic retention time of the reaction tank is 0.8h;

[0045] 3) Pump the effluent from the primary reaction tank into the primary sedimentation tank, the hydraulic retention time is 1h, and pump the settled sludge into the sludge thickening tank;

[0046] 4) Pump the effluent from the primary ...

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Abstract

The invention discloses a processing and recycling method of waste water discharged from a stainless steel pickling process. The method comprises the following steps that: waste water discharged from a stainless steel pickling process is pre-treated and sequentially pumped into a first reaction tank and a first sedimentation tank, lime cream and a coagulant aid are added, and fluorinions in the waste water are removed by sedimentation; the resulting water from the first sedimentation tank is pumped into an oxidation tank, and Fe<2+> in the waste water is oxidized into Fe<3+> through aeration; the resulting water from the oxidation tank is sequentially pumped into a second reaction tank and a second sedimentation tank, lye and a coagulant aid are added, and heavy metal ions such as Cr<3+>, Fe<3+> and Ni<2+> are removed by sedimentation; the resulting water from the second sedimentation tank is sequentially pumped into a pH back regulating tank, a middle water tank and a sand filter for carrying out a profound treatment, and the filtered water can be reused directly; Sludge in the first sedimentation tank and the second sedimentation tank is pumped into a sludge thickener, and is dehydrated by press filtering; sludge supernatant, filtrate and sand filter backwashing water are pumped into a regulating tank for a cycling treatment. According to the present invention, a graded processing measurement upon stainless steel pickling waste water is adopted, and standardized waste water discharging and recycling are realized. With the method provided by the present invention, a secondary pollution is avoided. The method is economical, and has good applicability.

Description

technical field [0001] The invention belongs to the technical field of environmental engineering and relates to a method for treating and reusing stainless steel pickling wastewater. Background technique [0002] With the rapid development of society and economy, stainless steel and its products are widely used because of their excellent corrosion resistance and good appearance. Because stainless steel inevitably undergoes annealing, normalizing, quenching, welding and other processing processes during the production process, black oxide scales often appear on the surface. Oxide scale not only affects the appearance quality of stainless steel, but also has an adverse effect on the subsequent processing of the product. Therefore, it must be removed by surface treatment methods such as pickling and polishing before subsequent processing. During this process, a large amount of F - 、Cr 6+ 、Cr 3+ , Fe 3+ , Fe 2+ and Ni 2+ If this kind of wastewater is discharged directly, ...

Claims

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Application Information

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IPC IPC(8): C02F9/04C02F1/56C02F1/76
Inventor 叶舟傅正杰万先凯杨斌
Owner HAIYUAN ENVIRONMENTAL SCI & TECH
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