Method for removing hexavalent chromium in chromium slag

A technology of hexavalent chromium and chromium slag, which is applied in the field of removal of hexavalent chromium in chromium slag, can solve the problems of damaging human health and polluting the environment, and achieves the effect of low price, simple operation, and realization of recycling

Inactive Publication Date: 2021-10-08
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chromium slag has been washed by rainwater for a long time, and hexavalent chromium ions will also be leached, which not only seriously pollutes the environment, but also damages human health

Method used

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  • Method for removing hexavalent chromium in chromium slag
  • Method for removing hexavalent chromium in chromium slag

Examples

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Embodiment 1

[0027] A method for removing hexavalent chromium in chromium slag, specific operation steps:

[0028] (1) Grind the particle size of the chromium slag to be treated to 75um, weigh 30g of chromium slag containing hexavalent chromium, put 150ml of sulfuric acid with a concentration of 0.5mol / L into a three-necked flask, and place the three-necked flask in a constant temperature water bath Stir on the pot to leach Cr 6+ , the temperature is controlled at 30°C, the rotational speed is controlled at 300r / min, and the leaching time is 3h.

[0029] (2) Weigh 10g of sawdust and put it into a beaker, add 50ml of 70% concentrated sulfuric acid, put it in a constant temperature water bath for hydrolysis, control the hydrolysis temperature at 40°C, and control the hydrolysis time at 30min.

[0030] (3) After the stirring and leaching in step (1) ends, filter and remove the filter residue, add the sawdust solution hydrolyzed in step (2), and reduce the hexavalent chromium leached in the c...

Embodiment 2

[0034] A method for removing hexavalent chromium in chromium slag, specific operation steps:

[0035] (1) Grind the chromium slag to be treated, weigh 25g, add 125ml of sulfuric acid with a concentration of 0.5mol / L, stir and leach Cr 6 + , the temperature is controlled at 40°C, and the leaching time is 4h.

[0036] (2) Weigh 15g of sawdust, add 75ml of 80% concentrated sulfuric acid for hydrolysis, control the hydrolysis temperature at 50°C, and control the hydrolysis time at 50min.

[0037] (3) After the stirring and leaching in step (1) ends, filter and remove the filter residue, add the sawdust solution hydrolyzed in step (2), and reduce the hexavalent chromium leached in the chromium residue, the temperature is controlled at 60 ° C, and the time is 3h.

[0038] (4) Utilize ultraviolet spectrophotometry to measure hexavalent chromium concentration in the upper clear night, obtain hexavalent chromium removal rate 92.6%, add sodium hydroxide, control solution pH to 7-9, m...

Embodiment 3

[0041] A method for removing hexavalent chromium in chromium slag, specific operation steps:

[0042] (1) Grind the chromium slag to be treated, weigh 30g, add 150ml of sulfuric acid with a concentration of 1mol / L, and stir to leach Cr 6 + , the temperature is controlled at 50°C, and the leaching time is 4h.

[0043] (2) Weigh 10 g of sawdust, add 50 ml of 90% concentrated sulfuric acid for hydrolysis, control the hydrolysis temperature at 60° C., and control the hydrolysis time at 50 minutes.

[0044] (3) After stirring and leaching in step (1), remove the filter residue by filtration, add the sawdust solution hydrolyzed in step (2), and reduce the hexavalent chromium leached from the chromium residue, the temperature is controlled at 60°C, and the time is 3h .

[0045] (4) Utilize ultraviolet spectrophotometry to measure hexavalent chromium concentration in the upper clear night, obtain hexavalent chromium removal rate 96.2%, add sodium hydroxide, control solution pH to 7...

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Abstract

The invention relates to a method for removing hexavalent chromium in chromium slag and belongs to the technical field of chromium slag detoxification. The method comprises the following steps that the chromium slag is ground until the particle size diameter is about 75 microns, sulfuric acid with a certain concentration is added to leach out hexavalent chromium, then biomass hydrolyzed by concentrated sulfuric acid is added, alkali is added after acid leaching reduction reaction to enable trivalent chromium ions to generate chromium hydroxide precipitate, and then solid-liquid separation is carried out; and filter residues obtained through separation are detoxified chromium residues, obtained liquid is filtrate, the treated supernatant liquid can completely meet the national sewage discharge standard, and the nontoxic filter residues can be used as a roadbed material or a filling material or can be comprehensively used. The method is simple in technological operation process, thorough in harmlessness and low in energy consumption, the used biomass is low in price and free of pollution, the yellowing phenomenon can be avoided, and the problems of toxicity and pollution of the chromium slag can be effectively solved.

Description

technical field [0001] The invention belongs to the technical field of chromium slag detoxification, and in particular relates to a method for removing hexavalent chromium in chromium slag. Background technique [0002] Chromium salt is an indispensable series of products in the national economy, mainly used in chemical industry, electronic technology, printing and dyeing, ceramics, catalyst and so on. In the process of producing metal chromium and chromium salt products, a large amount of discarded chromium slag will be produced, and it is a highly toxic hazardous waste. Chromium slag has been washed by rain for a long time, and hexavalent chromium ions will also be leached, which not only seriously pollutes the environment, but also destroys human health. The high toxicity of chromium slag comes from the strong oxidizing hexavalent chromium ion, which can cause cancer and induce gene mutation. Contents of the invention [0003] Aiming at the deficiencies of existing ch...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00B09B5/00
CPCB09B3/00B09B5/00Y02W30/78
Inventor 金哲男郑飞贤邹明君郑天昊杨洪英佟琳琳
Owner NORTHEASTERN UNIV
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