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Recycling processing method for wastewater produced by processing stainless steel

A treatment method, stainless steel technology, applied in metallurgical wastewater treatment, neutralized water/sewage treatment, oxidized water/sewage treatment, etc., can solve the problem of high concentration of heavy metals, and achieve the effect of high recovery value

Inactive Publication Date: 2010-02-17
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The present invention aims at the characteristics of "three highs and one low" of current stainless steel processing wastewater (pickling residue discharged from pickling tanks and cleaning wastewater): high acidity (H + Concentration 1×10 -4 ~5mol / L), high fluorine content (≥50mg / L), high heavy metal concentration (≥200mg / L), COD Cr Low (≤300mg / L), a set of low-cost, easy-to-control, and efficient wastewater treatment process is proposed

Method used

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  • Recycling processing method for wastewater produced by processing stainless steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] A stainless steel pipe drawing enterprise produces 1200m of wastewater 3 / d, its acidity varies widely (H + concentration from 10 -1 change to 5mol / L), the specific water quality conditions are shown in Table 1.

[0053] Table 1 Water quality parameters (unit: mg / L)

[0054] COD Cr

SS

total chromium

total iron

Ni 2+

F -

300

200

500

1000

500

500

[0055] Utilize technique and equipment of the present invention to carry out the technological process of wastewater treatment as follows:

[0056] (1) The waste water passes through the grid to remove the large solid particles of the waste water, and the removal rate is greater than 80%. Then enter the regulating tank for homogenization.

[0057] (2) The wastewater in the regulating tank is pumped up to CaCO 3 filter bed, generating CaF 2 , F - Go greater than 90%. After the wastewater passes through the filter bed, the pH value is adjus...

Embodiment 2

[0065] A stainless steel decorative building material enterprise in a machinery factory produces 400m of wastewater 3 / d, the acidity of wastewater varies widely (H + concentration from 10 -3 changed to 2.5mol / L), the specific water quality conditions are shown in Table 2.

[0066] Table 2 Water quality parameters (unit: mg / L)

[0067] COD Cr

SS

total chromium

total iron

Ni 2+

F -

150～260

80～150

460

800

400

400

[0068] Utilize technique and equipment of the present invention to carry out the technological process of wastewater treatment as follows:

[0069] (1) The waste water passes through the grid to remove large solid particles in the waste water, and the removal rate is greater than 85%. Then enter the regulating tank for homogenization.

[0070] (2) The wastewater in the regulating tank is pumped up to CaCO 3 filter bed, generating CaF 2 , F - The removal rate is greater than 82%. ...

Embodiment 3

[0078] The waste water produced in the stainless steel parts processing workshop of a large-scale comprehensive machinery factory in an industrial park is 2000m 3 / d, the acidity of wastewater varies widely (H + concentration from 10 -4 change to 1mol / L), the specific water quality conditions are shown in Table 3.

[0079] Table 3 Water Quality Parameters (Unit: mg / L)

[0080] COD Cr

SS

total chromium

total iron

Ni 2+

F -

200～300

150～300

500～600

1000～1200

500～600

450～650

[0081] Utilize technique and equipment of the present invention to carry out the technological process of wastewater treatment as follows:

[0082] (1) The waste water passes through the grid to remove the large solid suspended matter in the waste water, and the removal rate is greater than 80%. Then enter the regulating tank for homogenization.

[0083] (2) The wastewater in the regulating tank is pumped up to CaCO 3 fil...

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Abstract

The invention relates to a recycling processing method for wastewater produced by processing stainless steel, which comprises the following steps: after acid-washing residual liquid and washing wastewater are carried out wastewater deslagging, homogenizing; pumping into a CaCO3 filter bed to adjust the pH to 4.0-5.5 and removing F<->; adding an oxidizing agent into discharge water, oxidizing Fe<2+> into Fe<3+> and generating Fe(OH)2 and Fe(OH)3; after the Fe(OH)2, the Fe(OH)3 and CaF2 are deposited, recovering; adopting two-level coagulating sedimentation on supernatant liquid; adding alkali to adjust the pH to 8.0-9.5 in the first level; continuously adding the alkali to adjust the pH to 10.0-11.0 in the second level and adding CaCl2 and a flocculating agent to deposit sludge containing chromium and nickel; adding acid liquor into the discharge water to adjust the pH to 6.0-9.0 and filtering residual F<-> and suspended matters to reach the standard and recover; carrying out dehydration separation on the sludge containing ferrum and the sludge containing chromium and nickel; adding strong acid into the sludge containing chromium and nickel to dissolve; adopting two-level alkali adding coagulating sedimentation on the wastewater of a dissolving pool to obtain a Cr(OH)3 sediment and a Ni(OH)2 sediment or a NiCO3 sediment; carrying out sludge-water separation and recovering to obtain chromium and nickel metal or the compound thereof; and using supernatant liquid and the discharge water of a press filter for homogenization.

Description

technical field [0001] The invention belongs to the technical fields of environmental protection and chemical industry, and relates to a method for treating stainless steel processing wastewater and resource recovery, in particular to a method for treating the wastewater produced by processing stainless steel up to the standard and recovering heavy metal ions such as nickel and chromium in the wastewater. Background technique [0002] Stainless steel is widely used because it is not easy to corrode, pit, rust or wear, and has high strength. Chromium-containing stainless steel also combines mechanical strength and high ductility, and occupies a large market share in industrial production, but its production and processing are seriously polluted. The mixed acid of nitric acid and hydrofluoric acid is used for pickling during processing, which will produce a large amount of high-acidity wastewater, which contains F - , Fe 2+ and heavy metal ions such as nickel and chromium. ...

Claims

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Application Information

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IPC IPC(8): C02F9/04C01G53/00C01G37/00C22B7/00C22B23/00C22B34/32C01F11/22C01G49/02C02F1/66C02F1/72C02F1/52C02F103/16
Inventor 赵伟荣杨勇
Owner ZHEJIANG UNIV
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