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Method for recycling precious metals from stainless steel acid pickling sludge

A pickling sludge and stainless steel technology, applied in the direction of improving process efficiency, can solve problems such as high energy consumption and operating costs, secondary air pollution, complex operation and management, etc., achieve low production costs, reduce pollution, and solve resource problems effect of shortage

Inactive Publication Date: 2014-04-02
王洪
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The first method, land use, directly using the pickling sludge to the land will cause secondary pollution, which is not advisable; the second method, discharging the pickling sludge to the sea, will cause pollution to the ocean, which is not advisable; Three methods, sludge incineration, this treatment method takes a high proportion in Japan, Germany, Austria and other countries. Generally, the sludge in large sewage plants is harmless through incineration, and the heat energy generated can be recycled, and the volume and volume of sludge can be reduced. The degree is very high, but the main problem is that the incineration investment is huge, the operation management is complicated, and the energy consumption and operation cost are both high
At the same time, the toxic gas produced by incineration will cause secondary air pollution

Method used

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  • Method for recycling precious metals from stainless steel acid pickling sludge

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Raw materials: 5000kg of low-grade stainless steel sludge, of which Ni 0.8%, Co 0.03%, Cu0.5%, according to figure 1 Described processing step, concrete steps are as follows:

[0028] 1. First put the sludge into the central drive high-efficiency thickener for thickening, add flocculant polyacrylamide (PAM) accounting for 3‰ of the sludge weight into the thickener, and then pass through a 100m2 filter press to make the filter cake The moisture content is 11%.

[0029] 2. Add concentrated sulfuric acid with a mass concentration of 98% to the filter cake to make the pH value reach 1.6, keep the temperature at 90°C, stir evenly at a stirring speed of 80rpm for 4 hours, and then filter through a 100m2 filter press to separate the filtrate. Determine the iron content in the filtrate.

[0030] 3. The filtrate is adjusted with soda ash (or sodium bicarbonate) at room temperature, and when the pH of the filtrate is kept at 3.5, add hydrogen peroxide with a mass concentra...

Embodiment 2

[0037] Raw materials: 5000kg of low-grade stainless steel sludge, of which Ni 0.9%, Co 0.025%, Cu0.8%, according to figure 1 The process steps described.

[0038] 1. Put the sludge into a center-driven high-efficiency thickener for thickening. In the thickening project, add flocculant polyacrylamide (PAM) accounting for 3‰ of the sludge weight, and then pass through a 100m2 filter press to make the filter cake thicker. The moisture content is 9%.

[0039] 2. Add concentrated sulfuric acid with a mass concentration of 98% to make the pH value reach 1.5, keep the temperature at 80-100°C, stir evenly at a speed of 80rpm for 6 hours, and then filter through a 100m2 filter press to separate the filtrate. Determine and analyze the iron content in the filtrate.

[0040] 3. At room temperature, keep the pH of the filtrate at 3.2, add hydrogen peroxide with a mass concentration of 30% (the amount of hydrogen peroxide added is about 0.5-1% of the total weight of the filtrate) to ...

Embodiment 3

[0046] Raw materials: 5000kg of low-grade stainless steel sludge, of which Ni 0.6%, Co 0.05%, Cu0.5%, according to figure 1 The process steps described.

[0047] 1. First put the sludge into the thickener for thickening. In the thickening project, add flocculant polyacrylamide (PAM) accounting for 3‰ of the sludge weight, and then filter through a 100m2 filter press to make the moisture content of the filter cake 12%. .

[0048] 2. Add sulfuric acid with a mass concentration of 98% to make the pH value reach 1.5, keep the temperature at 80°C, stir evenly at a speed of 80rpm for 8 hours, and filter through a 100m2 filter press.

[0049] 3. At room temperature, keep the pH of the filtrate at 3.0 by adding hydrogen peroxide with a mass concentration of 30% (the amount of hydrogen peroxide added is about 0.5-1% of the total weight of the filtrate) to oxidize the Fe element, and then add sodium carbonate to make the solution The pH value is maintained at 3.0. At this time, a...

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Abstract

The invention provides a method for recycling precious metals from stainless steel acid pickling sludge, belonging to the field of non-ferrous metallurgy and waste utilization. The method mainly comprises the following steps: 1) thickening and filter pressing; 2) leaching; 3) iron removal and filter pressing; 4) P204 extraction: filtering and clarifying the mother liquid and feeding into a P204 extraction box; performing continuous saponification and counter-current extraction, and separating out an organic phase A and a filtrate A; extracting to remove impurity elements such as Zn, Cu, Mn, Ca and the like; 5) P507 extraction: feeding the filtrate A separated by the step 4) into a P507 extraction box, performing continuous saponification and counter-current extraction in the extraction box at room temperature, and separating out an organic phase B and a filtrate B; performing reverse extraction of the organic phase B by use of dilute hydrochloric acid to obtain a high-purity cobalt chloride solution, and enriching nickel in the filtrate B by use of dilute sulphuric acid to obtain a high-purity high-concentration nickel sulfate solution. The method provided by the invention finally obtains products such as copper sulfate, nickel sulfate, high-purity nickel, cobalt oxalate and the like, realizes resource recycling of precious metals in sludge, and has the comprehensive benefits of economic benefits, environmental benefits and social benefits.

Description

technical field [0001] The invention belongs to the field of nonferrous metallurgy and recycling, in particular to a method for recycling precious metals from stainless steel pickling sludge. Background technique [0002] In the production process of stainless steel, in order to obtain better surface quality, it needs to undergo pickling surface treatment such as sulfuric acid and hydrofluoric acid before cold rolling, resulting in a large amount of pickling waste liquid containing toxic and harmful substances such as cobalt, nickel and copper. The vast majority of stainless steel enterprises use lime neutralization sedimentation method for treatment, and a large amount of heavy metal sludge is produced, which belongs to industrial hazardous waste. Heavy metals in sludge exist in the form of carbonate, hydroxide precipitation, etc. If they are not treated, they are randomly piled up or simply landfilled, heavy metals are easily leached and diffused into the natural environm...

Claims

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Application Information

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IPC IPC(8): C22B7/00C22B23/00C22B15/00
CPCY02P10/20
Inventor 王洪胡炳堂周海涛
Owner 王洪
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