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Method for recycling heavy metal resources of stainless steel pickling waste water neutralization sludge

A technology of pickling wastewater and resource recovery, applied in chemical instruments and methods, water/sludge/sewage treatment, sludge treatment, etc., can solve the problems of complexity, low recovery rate of nickel and chromium, and achieve low loss of nickel and chromium , high recovery efficiency, good recovery effect

Inactive Publication Date: 2012-09-12
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the complex process of neutralizing sludge in stainless steel pickling wastewater in the prior art, and the shortcomings of low nickel and chromium recovery rates, and provide a method for recovering heavy metal resources from neutralizing sludge in stainless steel pickling wastewater. According to the characteristics of heavy metal ions in the sludge, the invention suppresses the leaching of iron and focuses on the recovery of valuable resources such as nickel, manganese, and chromium. High efficiency and good effect, the present invention realizes the harmless disposal of sludge, the up-to-standard discharge of process water and the resource recovery of heavy metals, has comprehensive benefits of economic benefits, environmental benefits and social benefits, and has broad prospects for popularization and application

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0028] The neutralized sludge of stainless steel pickling wastewater in this example comes from a sewage treatment plant in a stainless steel industrial park in Dafeng, Jiangsu. The sludge is obtained by treating stainless steel pickling wastewater with calcium chloride, lime and PAM. The main metal ion content is shown in Table 1. shown.

[0029] Table 1 Main metal ion content of stainless steel pickling wastewater and sludge in Example 1

[0030] element Fe mn Ni Cr Content g / kg 157.2 2.8 30 23.3

[0031] A kind of stainless steel pickling wastewater neutralization sludge heavy metal resource recovery method of the present embodiment, its specific steps are:

[0032] (1) Acid leaching: Take 40 g of the above sludge into a 500 mL three-neck flask, add 200 mL of water, stir evenly, add 80% sulfuric acid dropwise until the pH is stable at about 2.0, leaching for 50 min, then warming up to 95 °C, and then Add 8 mL, 360 g / L Na 2 SO 4 Solution (in...

Embodiment 2

[0037] The sludge and basic steps used in this example are the same as those in Example 1, except that in step (1), 90% sulfuric acid is added dropwise until the pH is stable at about 2.5, and after leaching for 10 min, the temperature is raised to 85°C, and then Na 2 SO 4 solution (in this example, the mass ratio of dry sludge to sodium sulfate is 5:1), put the three-necked flask in a water bath at 85°C, and keep stirring, then add jarosite crystal seeds (the dosage of the seed crystals is 10g / L), while adding 10% Na 2 CO 3 The pH value of the solution was controlled at 2.5, and after the iron removal reaction of jarosite was carried out for 5 h, 10% Na 2 CO 3 , adjust and control the pH value to 3.5, and add goethite seed crystals (the dosage of the seed crystals is 1 g / L), carry out the goethite reaction, and continue to react for 5 h. Increasing the pH is beneficial to inhibit the leaching of iron, but it will As a result, the leaching rate of nickel and chromium decre...

Embodiment 3

[0039] The sludge and basic steps used in this example are the same as in Example 1, the difference is that in step (1), 50% sulfuric acid is added dropwise until the pH is stable at 1.0, after leaching for 80 min, the temperature is raised to 75°C, and then Na 2 SO 4 solution (the mass ratio of dry sludge to sodium sulfate in this example is 25:1), put the three-necked flask in a 75°C water bath, and keep stirring, then add jarosite crystal seeds (the dosage of the seed crystals is 1 g / L), while adding 10% Na 2 CO 3 The pH value of the solution was controlled at 1.5, and after the iron removal reaction of jarosite was carried out for 1 h, 10% Na 2 CO 3 , adjust and control the pH value to 2.5, and add goethite seed crystals (the dosage of the seed crystals is 10 g / L), carry out the goethite reaction, and continue the reaction for 1.0 h; take 200mL in step (2) and step (1) Add potassium permanganate according to 130% of the amount required for the theoretical oxidation of ...

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Abstract

The invention discloses a method for recycling heavy metal resources of stainless steel pickling waste water neutralization sludge and belongs to the technical field of recycling of sludge after sewage treatment. The method comprises the following steps of: 1) performing acid pickling, namely extracting the stainless steel pickling waste water neutralization sludge by using sulfuric acid as extractant, and adding an additive to inhibit the leaching of ferrum; 2) oxidizing, namely adding oxidant into a leaching solution to oxidize Mn(II) into manganese dioxide; 3) performing ion exchange, allowing a solution obtained after oxidation to pass through an anion exchange column, enriching and recycling hexavalent chromium, adsorbing and saturating, regenerating by using regenerant, and recycling chromate from a regeneration solution; and 4) performing neutralization precipitation, namely recycling nickelous hydroxide from ion exchange effluent by a neutralization precipitation method. By the method, ferrum is inhibited at an acid pickling section, the acid pickling is performed while ferrum is removed, the multi-stage multi-step recycling of manganese, chromium, and nickel metal resources can be realized, the innocent treatment of sludge and recycling of heavy metal are realized, and the method has comprehensive benefit of economic benefit, environmental benefit and social benefit.

Description

technical field [0001] The invention relates to a method for recovering manganese, nickel and chromium resources from heavy metal sludge produced after neutralization of waste water in stainless steel and steel wire rope production and related surface treatment industries, and more specifically relates to a neutralization method for stainless steel pickling waste water Recovery method of mud heavy metal resources. Background technique [0002] The acid wastewater generated during the surface treatment of stainless steel is generally treated by neutralization precipitation method, and a large amount of sludge containing heavy metals such as nickel, chromium, and manganese is produced, which belongs to industrial hazardous waste. Heavy metals in sludge exist in the form of carbonate, hydroxide precipitation, etc. If they are randomly stacked or simply landfilled without treatment, heavy metals are easily leached and diffused into the natural environment, which will have a sign...

Claims

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Application Information

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IPC IPC(8): C22B7/00C22B3/08C22B3/20C02F11/00B09B3/00C22B47/00C22B34/32C22B23/00
CPCY02P10/20
Inventor 刘福强侯鹏杨才杰吴秋原凌晨陶学文李爱民
Owner NANJING UNIV
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