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Method for harmless and recycling treatment of stainless steel acid washing waste water neutralization sludge

A technology for pickling wastewater and stainless steel, applied in water/sludge/sewage treatment, sludge treatment, chemical equipment and methods, etc. The effect of good effluent quality, high recovery efficiency and short process flow

Active Publication Date: 2012-08-01
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the ferric hydroxide colloid formed during iron removal by this method has a strong adsorption effect on metals such as nickel and chromium, and is easy to form co-precipitation, causing serious losses of nickel and chromium and secondary pollution.
Moreover, this method also has problems such as difficult phase separation, entrained loss of extractant, and serious secondary pollution.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The neutralized sludge of stainless steel pickling wastewater was taken from a stainless steel pickling wastewater sewage treatment plant in Yancheng City, and the metal content in it was measured by digestion as follows:

[0029] element Fe mn Ni Cr Content (mg / kg) 189924 4186 55406 8719

[0030] 1) Leaching: Dry the neutralized sludge of stainless steel pickling wastewater for 24 hours, and pass through a 60-mesh sieve after grinding to obtain powdery sludge. Mix 400g of sludge and 1600mL of water in a 2L beaker, add 1+1 sulfuric acid ( A total of 180mL) to maintain pH 1.0-1.5, leaching at room temperature for 1.5 hours. Obtain 1520mL of leach solution, the concentration of each metal element in the leach solution and the leaching rate are as follows:

[0031] element Fe mn Ni Cr Concentration (mg / L) 27989 1082 14435 2260 Leaching rate 56% 98.2% 99% 98.5%

[0032] 2) Iron removal: Keep the total iron...

Embodiment 2

[0037] The neutralized sludge of stainless steel pickling wastewater was taken from a stainless steel pickling wastewater sewage treatment plant in Yancheng City, and the metal content in it was measured by digestion as follows:

[0038] element Fe mn Ni Cr Content (mg / kg) 113309 7068 6101 15610

[0039] 1) Leaching: Dry the neutralized sludge of stainless steel pickling wastewater for 24 hours, and pass through a 60-mesh sieve after grinding to obtain powdery sludge. Mix 400g of sludge and 1600mL of water in a 2L beaker, add 1+1 sulfuric acid ( A total of 160mL) to maintain the pH value of 1.0-1.5, leaching reaction for 1.5 hours. Obtain 1500mL of leach solution, the concentration of each metal element in the leach solution and the leaching rate are as follows:

[0040] element Fe mn Ni Cr Concentration (mg / L) 18734 1838 1614 4038 Leaching rate 62% 97.5% 99.2% 97%

[0041] 2) Iron removal: Keep the total iron ...

Embodiment 3

[0046] The sludge was in the same batch as in Example 1. During the iron removal process, the pH value was controlled to be 4.0-4.5, the iron removal cycle was reduced to about 20 minutes, and the chromium loss rate rose to 17.6%. The oxidation process is the same as in Example 1, with a treatment capacity of 47BV. Recover nickel process with embodiment 1.

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PUM

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Abstract

The invention discloses a method for harmless and recycling treatment of stainless steel acid washing waste water neutralization sludge, belonging to the field of harmful and valuable heavy metal resource recovery. The stainless steel acid washing waste water neutralization sludge is leached out by sulphuric acid, harmful and poisonous metals manganese, nickel and chromium enter into the leachate, and harmless treatment is carried out on the sludge. Separation, enrichment and recovery of metal resources of iron, manganese, chromium and nickel in the leachate are realized by adopting goethite method, potassium permanganate oxidation method, anion resin exchange method and chelate resin absorption method respectively, and effluent up to the standard is discharged after treatment or is returned to water consuming link in technologic process. The method of the invention has short technological flow, simple operation, management convenience, high recovery rate of valuable metal resources of manganese, nickel and chromium, recycling of multiple valuable metals is realized while the sludge is subject to harmless treatment, and unification of economic benefit, environmental benefit and social benefit is realized.

Description

technical field [0001] The present invention relates to the harmless and resourceful disposal method of the neutralized sludge in stainless steel production, electroplating industry and related surface treatment industrial wastewater, in particular to the harmless disposal and recycling of the neutralized sludge in the toxic waste water of the stainless steel pickling industry. A method for resource recovery of valuable metals. Background technique [0002] During the surface pickling process of stainless steel, a large amount of acid wastewater containing heavy metal ions such as nickel, chromium, and manganese is produced. At present, most stainless steel pickling enterprises still use the traditional neutralization precipitation method to remove heavy metals, resulting in a large amount of toxic sludge containing various heavy metals. The heavy metals in this kind of sludge mostly exist in the state of hydroxide, oxide, carbonate, etc., which are very unstable and easy t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F11/00C02F9/04
Inventor 刘福强杨才杰李兰娟侯鹏王津南李爱民戴建军
Owner NANJING UNIV
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