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A kind of method for chromium slag extraction chromic acid leaching pretreatment

A pretreatment and chromium slag technology, applied in the direction of improving process efficiency, etc., can solve the problems of unrecoverable trivalent chromium, difficulty in elution of chromium, and many impurities, and achieve the effect of reducing raw material consumption, reducing chromium content, and high purity

Active Publication Date: 2022-02-25
HUBEI ZHENHUA CHEMICAL CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method can recover part of hexavalent chromium, but cannot recover trivalent chromium in chromium slag, and the recovery rate of hexavalent chromium is only 60-80%.
[0006] CN 106048239A discloses a treatment method for resource recycling of waste slag containing hexavalent chromium. The method includes: adding a mineralizer to the waste slag solution containing hexavalent chromium and stirring thoroughly to obtain a mixed solution; the mineralizer It is sodium chlorate, sodium perchlorate and hydrochloric acid; use hydrothermal method or direct heating to treat the mixed solution; after heating, cool naturally, stand and separate, wash and dry the filter residue, recover the chromium-containing solution and return it to the working section, or Chromium recovery is carried out, and chromium is recovered in the form of chromium hydroxide. This method can recover most of the hexavalent chromium, but it is difficult to dissolve chromium that exists in a stable crystal phase, and there are many impurities in chromium hydroxide products

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  • A kind of method for chromium slag extraction chromic acid leaching pretreatment

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Experimental program
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Effect test

Embodiment 1

[0081] This embodiment provides a method for chromium slag extracting chromium acid leaching pretreatment, the chromium slag is calcium-free roasted chromium slag, the main component and content are: Cr 2 o 3 9.84wt%, Al 2 o 3 18.63wt%, SiO 2 11.65wt%, Fe 2 o 3 37.53wt%, CaO2.04wt%, MgO19.71wt%, Na 2 O2.15wt%, here only expresses the component content by oxides, not the phase composition;

[0082] The process flow diagram of the method is as figure 1 shown, including the following steps:

[0083] (1) After the calcium-free roasted chromium slag is crushed, the liquid-solid ratio is 5m 3 : 1t carries out wet ball milling, filters and obtains ball milling slag and ball milling liquid, and the average particle size of described ball milling slag is 120 μ m, adds the sulfuric acid solution that concentration is 10wt% in ball milling slag and carries out one-stage leaching desiliconization, aluminum removal, one-stage leaching The liquid-solid ratio is 4m 3 : 1t, leaching...

Embodiment 2

[0089] This embodiment provides a pretreatment method for extracting chromium from chromium slag, the chromium slag is calcium-free roasted chromium slag, and its main components and contents are the same as in Example 1.

[0090] The method comprises the steps of:

[0091] (1) After the calcium-free roasted chromium slag is crushed, the liquid-solid ratio is 1m 3 : 1t carries out wet ball milling, filters and obtains ball milling slag and ball milling liquid, and the average particle size of described ball milling slag is 150 μ m, and adding concentration in ball milling slag is that the hydrochloric acid solution of 15wt% carries out primary leaching desiliconization, aluminum removal, primary leaching The liquid-solid ratio is 0.25m 3 : 1t, leaching temperature is 30 ℃, and leaching time is 120min, filters and obtains primary acid leaching solution and primary acid leaching residue, and the concentration of silicon in the primary acid leaching solution is 64.72g / L;

[009...

Embodiment 3

[0097] This embodiment provides a pretreatment method for extracting chromium from chromium slag, the chromium slag is calcium-free roasted chromium slag, and its main components and contents are the same as in Example 1.

[0098] The method comprises the steps of:

[0099] (1) After the calcium-free roasted chromium slag is crushed, the liquid-solid ratio is 2.5m 3 : 1t carries out wet ball milling, filters and obtains ball milling slag and ball milling liquid, and the average particle size of described ball milling slag is 100 μ m, and adding concentration to ball milling slag is that the sulfuric acid solution of 1wt% carries out one-stage leaching desiliconization, aluminum removal, one-stage leaching The liquid-solid ratio is 5m 3 : 1t, leaching temperature is 95 ℃, and leaching time is 25min, filters and obtains primary acid leaching solution and primary acid leaching residue, and the concentration of silicon in the primary acid leaching solution is 49.53g / L;

[0100] ...

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Abstract

The invention provides a method for chromium extraction and acid leaching pretreatment of chromium slag. The method comprises: adding acid to the ball mill slag obtained after wet ball milling of chromium slag for primary leaching to obtain primary acid leaching solution and primary acid leaching slag; add acid again to the primary acid leaching residue for secondary leaching to obtain secondary acid leaching solution and secondary acid leaching residue; perform calcium-free roasting on the secondary acid leaching residue, and separate solid and liquid after leaching to obtain chromium extraction tail slag and leachate. The present invention realizes the deep removal of silicon-aluminum impurities and partial removal of elements such as magnesium and iron through the acid leaching pretreatment in the process of extracting chromium from chromium slag, increases the chromium content in chromium slag, facilitates subsequent roasting to extract chromium, and improves The recovery rate of chromium in the chromium slag is improved, and the harmless treatment of the chromium slag is realized at the same time; the removal of silicon-aluminum impurities in the method can reduce alkali consumption and reduce the liquid phase amount during roasting; in the described method, various The recycling of the solution reduces the consumption of raw materials, lowers the processing cost, is clean and pollution-free, and has broad application prospects.

Description

technical field [0001] The invention belongs to the technical field of solid waste utilization, and relates to a method for chromium extraction and acid leaching pretreatment of chromium slag. Background technique [0002] Chromium slag is the residue left by the leaching of chromium compounds from chromium-containing minerals, and is an associated solid waste in the processing of various chromium-containing minerals. The traditional chromium salt production process is the calcium roasting process of chromite. Because a large amount of calcium filler needs to be added during the roasting process, the discharge of chromium slag is large, the content of hexavalent chromium in the slag is high, and it contains carcinogens. It belongs to the eliminated technology, so there is no Calcium roasting process is currently the main method of chromium salt production, which solves the problem of large chromium slag discharge, but calcium-free roasted chromium slag still contains about 0...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B1/02C22B34/32
CPCC22B7/007C22B1/02C22B34/32Y02P10/20
Inventor 董玉明黄国强庆朋辉段静裴丽丽段祥云张红玲郭小峰徐红彬苏晓亮张懿段怀玉
Owner HUBEI ZHENHUA CHEMICAL CO LTD
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