A kind of method for recovering and preparing metallic chromium

A technology of metal chromium and metal chromium powder, which is applied in the field of metallurgy, can solve the problems of secondary pollution, large amount of sludge generation, and no recycling, etc., and achieve the effects of high-efficiency separation, accelerated reduction rate, and accelerated diffusion rate

Inactive Publication Date: 2016-02-24
GUANGXI SHENGLONG METALLURGICAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, after the trivalent chromium is obtained by these two methods, the solution is often neutralized, so that the trivalent chromium is precipitated into sludge and discarded.
Therefore, resulting in a large amount of sludge, easy to cause secondary pollution
And chromium is not being recycled as a valuable element

Method used

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  • A kind of method for recovering and preparing metallic chromium

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] A method for recovering and preparing metallic chromium, comprising the steps of:

[0028] (1) Add an appropriate amount of sodium sulfate or sodium dihydrogen phosphate to the chromium-containing solution to be treated, adjust the pH of the solution to 2, heat and stir at 50°C for 6 hours, and reduce the chromium (VI) in the chromium-containing solution to Chromium (III);

[0029] (2) Add an organic solvent to the solution treated in step (1), mix thoroughly, and leave to stand or centrifuge to separate phases to obtain a liquid-liquid phase system, the upper layer is an organic solvent phase, and all chromium (III) is transferred to the organic solvent phase middle;

[0030] (3) using an acid solution with a pH lower than 2.0 to recover the chromium (III) supported by the organic solvent;

[0031] (4) adjust the pH of the chromium solution that (3) step stripping reclaims gained is adjusted to 8.6, and chromium is precipitated with hydrate Cr(OH) nH 2 Precipitate i...

Embodiment 2

[0040] A method for recovering and preparing metallic chromium, comprising the steps of:

[0041] (1) Add an appropriate amount of sodium sulfate or sodium dihydrogen phosphate to the chromium-containing solution to be treated, adjust the pH of the solution to 4, heat and stir at 40°C for 7 hours, and reduce the chromium (VI) in the chromium-containing solution to Chromium (III);

[0042] (2) Add an organic solvent to the solution treated in step (1), mix thoroughly, and leave to stand or centrifuge to separate phases to obtain a liquid-liquid phase system, the upper layer is an organic solvent phase, and all chromium (III) is transferred to the organic solvent phase middle;

[0043] (3) using an acid solution with a pH lower than 2.0 to recover the chromium (III) supported by the organic solvent;

[0044] (4) adjust the pH of the chromium solution that (3) step back extraction reclaims gained is adjusted to 8.3, and chromium is precipitated with hydrate Cr(OH) nH 2 Precipi...

Embodiment 3

[0053] A method for recovering and preparing metallic chromium, comprising the steps of:

[0054] (1) Add an appropriate amount of sodium sulfate or sodium dihydrogen phosphate to the chromium-containing solution to be treated, adjust the pH of the solution to 3, heat and stir at 45°C for 6.5h, and reduce the chromium (VI) in the chromium-containing solution is chromium(III);

[0055] (2) Add an organic solvent to the solution treated in step (1), mix thoroughly, and leave to stand or centrifuge to separate phases to obtain a liquid-liquid phase system, the upper layer is an organic solvent phase, and all chromium (III) is transferred to the organic solvent phase middle;

[0056] (3) using an acid solution with a pH lower than 2.0 to recover the chromium (III) supported by the organic solvent;

[0057] (4) adjust the pH of the chromium solution that (3) step stripping reclaims gained is adjusted to 8.5, and chromium is precipitated with hydrate Cr(OH) nH 2 Precipitate in th...

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Abstract

A method for recycling and preparing metal chromium comprises the steps of recycling chromium element from discharged waste liquid and discharged waste material, and utilizing the recycled chromium element to prepare metal chromium. The method prevents environmental pollution, realizes application of chromium resources, is simple in technology and low in cost, and can obtain metal chromium products which can meet the use requirement.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for recovering and preparing metal chromium. Background technique [0002] Metallic chromium is a common industrial pollutant, which is mostly found in the wastewater of electroplating, tanning, smelting, printing and dyeing, pigment and textile industries, and often exists in the form of hexavalent and trivalent. Cr(VI) has strong toxicity. Its intake can affect the redox of cells, can combine with nucleic acid, stimulate the digestive tract and respiratory tract, have carcinogenic and mutagenic effects, and cause serious harm to human health. my country stipulates that the maximum allowable discharge standard of hexavalent chromium and its compounds in industrial wastewater is 0.5mg / L. In view of the fact that the toxicity of Cr(III) is much weaker than that of Cr(VI), the current common method is to reduce the hexavalent chromium in chromium wastewater...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B34/32C22B3/44C22B3/26
CPCY02P10/20
Inventor 李平
Owner GUANGXI SHENGLONG METALLURGICAL CO LTD
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