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Cleaning and detoxification treatment of chromium slag and extraction method of chromium

A chromium slag and cleaning technology, applied in the field of clean detoxification treatment of chromium slag and chromium extraction, can solve the problems of high processing cost, complicated process flow, and large consumption of chemical reagents, etc., and achieve chromium pollution control, simple process cleaning, and adsorption Effect of active site reduction

Active Publication Date: 2018-04-13
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The Chinese patent "Process for Recycling and Reusing Chromium Slag and Wastewater" (CN102699006A) takes into account the recovery of chromium and the reuse of slag. Under normal temperature conditions, the chromium slag is almost completely dissolved with acid, and then different precipitants are added respectively. Precipitation and separation of mixed ions in the solution, but this method needs to consume a large amount of chemical reagents such as acid and precipitant, and the process is complicated and the treatment cost is high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] 1) Take 0.5 kg of waste residue containing hexavalent chromium and put it into a hydrothermal kettle, then add water to make the solid-to-liquid ratio (w / w) 1:1, stir well, add hydrogen peroxide, so that the concentration of hydrogen peroxide in the system is 0.1mol / L, set the temperature at 130°C, and keep warm for 6 h.

[0038] 2) After 6 h, stop heating, cool down to room temperature naturally, and let stand for 24 h.

[0039] 3) After standing still, pour out the solution containing hexavalent chromium in the upper layer. Carry out centrifugal washing and dehydration to the residue after hydrothermal treatment, and dry the filter residue to obtain a white or white yellowish solid.

[0040] 4) Reuse the chromium-containing solution in production, or collect it in the wastewater treatment station for reduction, recovery, and purification treatment, add reducing agent (such as sodium sulfide, sodium bisulfite) and precipitant (NaOH), and distill the solution six The...

Embodiment 2

[0044] Take 1 kg of waste residue containing hexavalent chromium and put it into a hydrothermal kettle, then add water to make the solid-to-liquid ratio (w / w) 1:0.5, stir well, add hydrogen peroxide, and make the concentration of hydrogen peroxide in the system 1 mol / L, Set the temperature at 50 °C, keep it warm for 10 h, and let it stand for 48 h after stopping heating. Other technological process is identical with embodiment 1.

[0045] The concentration of hexavalent chromium leached from the original chromium residue in this example was 269 mg / L, and the concentration of hexavalent chromium leached from the filter residue after treatment was 2.12 mg / L.

Embodiment 3

[0047] Take 1.5kg of waste residue containing hexavalent chromium and put it into a hydrothermal kettle, then add water to make the solid-to-liquid ratio (w / w) 1:10, stir well, add hydrogen peroxide, so that the concentration of hydrogen peroxide in the system is 3 mol / L, Set the temperature at 200 °C, keep it warm for 2 h, and let it stand for 0.5 h after stopping heating. Other technological process is identical with embodiment 1.

[0048] The concentration of hexavalent chromium leached from the original chromium residue in this example was 277 mg / L, and the concentration of hexavalent chromium leached from the filter residue after treatment was 1.92 mg / L.

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Abstract

The invention discloses a method for cleaning and detoxifying chromium slag and extracting chromium, and belongs to the field of chromium slag cleaning and resource recycling. The method includes the specific steps that (1) water is added into waste slag containing hexavalent chromium and evenly mixed; (2) hydrogen peroxide is added into a solution obtained in the step (1) and fully mixed to obtain mixed liquor; (3) the mixed liquor is directly heated or heated through a hydrothermal method; (4) after heating, a solid-liquid mixture is naturally cooled to the room temperature, and then standing is conducted; (5) solid slag and chromium-containing supernatant are separated, and filter residues are washed with water and then dried; and (6) a chromium-containing solution is recovered and fed back to a station, or is subjected to chromium recovery. A mineralizer adopted by the method is environmentally friendly and free of pollution, the treated supernatant can be directly reused for a chromium salt production or application process, and the filter residues can be comprehensively utilized. According to the method, the process is clean and simple, investment is low, the effect is quickly achieved, hexavalent chromium can be recycled, and chromium pollution is effectively treated without causing secondary pollution.

Description

technical field [0001] The invention belongs to the field of cleaning treatment of chromium slag and recycling of resources, and in particular relates to a method for cleaning and detoxification treatment of chromium slag and chromium extraction. Background technique [0002] Chromium residue refers to the waste residue containing hexavalent chromium produced in the production and application of chromium salts. Hexavalent chromium is highly toxic and can cause cancer, and is listed as one of the eight most harmful chemicals to humans. my country's chromium salt production and consumption rank first in the world, and it is also the country that produces the most chromium slag. Millions of tons of chromium slag have been stockpiled urgently, which has brought serious pollution to soil and groundwater. However, my country's chromium ore resources are relatively poor, and the current proven reserves only account for 0.825% of the world's total reserves, which is a shortage of re...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B34/32
CPCC22B7/006C22B34/32Y02P10/20
Inventor 刘学明林璋刘炜珍荣文聪
Owner SOUTH CHINA UNIV OF TECH
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