Process for reclaiming chromium and aluminum by comprehensive treatment of sludge containing chromium-aluminium

A comprehensive processing and aluminum slime technology, applied in the direction of improving process efficiency, etc., can solve problems such as aluminum can not be recycled, high energy consumption, and resources can not be fully utilized, so as to achieve the effect of protecting the environment, realizing comprehensive utilization, and realizing resources

Inactive Publication Date: 2007-10-31
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method not only consumes a lot of energy, but also the aluminum in it cannot be recycled, the resources cannot be fully utilized, and the clean production of chromium salts cannot be realized.

Method used

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  • Process for reclaiming chromium and aluminum by comprehensive treatment of sludge containing chromium-aluminium

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Experimental program
Comparison scheme
Effect test

Embodiment approach 2

[0013] Add a certain amount of chromium-removing lotion in the chromium-containing aluminum mud with a water content of about 70%, control its liquid-solid ratio to be 5.0, carry out liquid-solid separation after stirring at 70° C. for 4 hours, and the chromium concentration in the gained liquid phase ( Take Na 2 Cr 2 o 7 .2H 2 O) is 100g / L, the band loss of chromium in solid phase aluminum mud (water content is about 70%) is 0.5%, aluminum (as Al(OH) 3 (calculated) content of 23%; then, add industrial grade soda sulfide while dechroming and aluminum slurrying, and the addition amount is 3kg / m 3 Slurry, the resulting slurry solution is dissolved in a sodium aluminate solution with a caustic molecular ratio of 3.0, the dissolution temperature is 120°C, and the dissolution time is 30 minutes. The dissolved slurry is separated by sedimentation, and the obtained supernatant (crude liquid) is filtered through a leaf , and then decompose the seed crystals to precipitate aluminum...

Embodiment approach 3

[0015] Add a certain amount of chromium-removing lotion in the chromium-containing aluminum mud with a water content of about 70%, control its liquid-solid ratio to be 3.0, carry out liquid-solid separation after stirring at 50° C. for 6 hours, and the chromium concentration in the gained liquid phase ( Take Na 2 Cr 2 o 7 .2H 2 O) is 120g / L, the band loss of chromium in solid phase aluminum mud (water content is about 70%) is 1.0%, aluminum (as Al(OH) 3 ) content of 18%; then, add industrial grade sodium sulfide while dechroming and aluminum slurrying, the addition amount is 6kg / m 3 Slurry, the resulting slurry solution is dissolved in a sodium aluminate solution with a caustic molecular ratio of 2.8, the dissolution temperature is 80°C, and the dissolution time is 60 minutes. The dissolution slurry is separated by sedimentation, and the obtained supernatant (crude liquid) is filtered through a leaf , and then decompose the seed crystals to precipitate aluminum hydroxide, ...

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Abstract

The invention discloses a craft to reclaim chromium and aluminum from chromic aluminum sludge, which comprises the following steps: adding wash solution with hexavalent chromium into chromic aluminum sludge; controlling liquid and sludge ratio; peptizing the chromic aluminum sludge; getting dispergation slurry; proceeding solid-liquid separation; getting filter liquor with hexavalent chromium; distilling; condensing; backing to chromate salt process flow; washing the filter cake for 2-3 times; getting expelling chromic aluminum sludge; pulping the expelling chromic aluminum sludge in evaporating mother liquid; controlling the particle with grain size at -100 order more than 95%; adding into technical grade Na2S; keeping warm for slurry; dissolving out; getting the dissolving slurry; adding into flocculant; separating compound with silicon, iron and trivalent chromium; washing the residue; backing to chromate salt process flow; reclaiming trivalent chromium; settling and separating sodium aluminate solution; seed-dissociating with Bayer method; getting aluminum hydroxide product. This invention can produce eligible aluminum hydroxide, which can protect environment effectively.

Description

[technical field] [0001] The invention belongs to a technique for recovering chromium and aluminum from chromium-containing aluminum mud in the industrial production of inorganic salts. [Background technique] [0002] The production of chromium salts from chromite is a very important part of the inorganic salt industry and an indispensable industrial sector in the national economy. It involves many industrial sectors such as pigments, leather tanning, medicine, and textiles. More than 20 percent of the total is related to chromate, and the production of chromium salt occupies a very important position in my country's modern national economy. However, due to the large amount of industrial waste water and waste residue produced by the existing soda ash roasting process for producing chromate, the environment is seriously polluted. Therefore, the research on the clean production process of chromate has been highly valued at home and abroad. The chromium-containing aluminum mud...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B3/00C22B3/20
CPCY02P10/20
Inventor 李小斌周秋生彭志宏刘桂华韩登仑张忠元杨昆山
Owner CENT SOUTH UNIV
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