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Pyrolytic treatment method for chromium slag

A treatment method and technology for chrome slag, which are applied in combustion methods, lighting and heating equipment, combustion types, etc., can solve the problems of difficult chrome slag treatment and high cost of microwave technology, reduce equipment investment and operating costs, and improve energy use. efficiency, reducing the cost of raw materials

Inactive Publication Date: 2007-10-17
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the cost of microwave technology is high, so it is difficult to be used in large-scale chromium slag treatment

Method used

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  • Pyrolytic treatment method for chromium slag

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] After the chromium residue is ground to 60 mesh, it is mixed with dewatered sludge (water content 80%), the mass ratio of chromium residue to sludge is 1:0.5, and the mixture is sent into the inner cylinder of the externally heated rotary furnace through a screw feeder for further processing. Preheating and drying, the mixture stays in the inner drum of the externally heated rotary kiln for 0.25 hours, so that the moisture content of the dried mixture is lower than 5%.

[0025] The reduction combustion furnace uses natural gas as fuel, and the air excess coefficient in the reduction combustion furnace is controlled to be 0.9. The temperature of the generated hot gas is about 500°C, and the oxygen content is less than 0.5%. The generated high-temperature hot gas is introduced into the internal heating type pyrolysis furnace.

[0026] Send the mixture preheated by the external heating rotary furnace into the internal heating pyrolysis furnace, and directly contact the high...

Embodiment 2

[0031] After grinding the chromium slag to 60 mesh, mix it with dewatered sludge (moisture content 60%), the mass ratio of chromium slag and sludge is 1:2, and send the mixture into the inner cylinder of the externally heated rotary furnace through a screw feeder. Preheating and drying, the mixture stays in the inner drum of the externally heated rotary kiln for 0.25 hours, so that the moisture content of the dried mixture is lower than 5%.

[0032] The reduction combustion furnace uses natural gas as fuel, and the air excess coefficient in the reduction combustion furnace is controlled to be 0.8. The temperature of the generated hot gas is 650°C, and the oxygen content is less than 0.5%. The generated high-temperature hot gas is introduced into the internal heating type pyrolysis furnace.

[0033] Send the mixture preheated by the external heating rotary furnace into the internal heating pyrolysis furnace, and directly contact the high temperature hot gas with a temperature of...

Embodiment 3

[0038] After grinding the chromium slag to 60 mesh, mix it with dewatered sludge (moisture content 60%), the mass ratio of chromium slag to sludge is 1:0.5, and send the mixture into the inner cylinder of an externally heated rotary furnace through a screw feeder for further processing. Preheating and drying, the mixture stays in the inner barrel of an externally heated rotary kiln for 4 hours, so that the moisture content of the dried mixture is lower than 5%.

[0039] The reduction combustion furnace uses natural gas as fuel, and the air excess coefficient in the reduction combustion furnace is controlled to be 0.8. The temperature of the generated hot gas is 500°C, and the oxygen content is less than 0.5%. The generated high-temperature hot gas is introduced into the internal heating type pyrolysis furnace.

[0040] Send the mixture preheated by the external heating rotary furnace into the internal heating pyrolysis furnace, and directly contact the high temperature hot gas ...

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Abstract

The invention relates to a thermolysis processing process of chromium slag, using dehydration mud from municipal sewage plant as an additive. The process comprises: firstly mixing the chromium slag and the mud in proportion and sending the mixture to an external heating type tilting furnace for preheat and dry, then sending the mixture to an interior heating type pyrolyzing furnace to carry out thermolysis reaction, wherein the high temperature hot reduction gas of the interior heating type pyrolyzing furnace enters from a reduction combustion furnace, and the pyrolysis products after being reduction treated are cooled and discharged. Exhaust gas of the interior heating type pyrolyzing furnace enters the external heating type tilting furnace after mixed with air via a dilution trap to dry the mixture of the chromium slag and the mud indirectly. The invention can detoxicate the chromium slag, meanwhile, treat the mud and use energy effectively, thus has obvious economic benefits and environmental benefits.

Description

technical field [0001] The invention relates to a pyrolysis treatment method for chromium slag, which uses sludge as a reducing agent to reduce hexavalent chromium in chromium slag through reducing atmosphere generated by sludge pyrolysis. The invention belongs to the chromium slag disposal technology in the field of environmental protection. Background technique [0002] Chromium slag is a by-product emitted during the production of dichromate. Because it contains water-soluble hexavalent chromium, it is extremely toxic. If it is stacked in the open air without treatment, it will cause varying degrees of pollution to groundwater sources, rivers or sea areas, and seriously endanger human health and the growth of animals and plants. [0003] Generally speaking, the current detoxification methods for chromium slag (that is, changing highly toxic hexavalent chromium into trivalent chromium) are divided into two categories: wet detoxification and dry detoxification. The wet me...

Claims

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Application Information

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IPC IPC(8): B22F9/30F23G7/14
Inventor 孔海南张大磊吴德意胡湛波隋艳明
Owner SHANGHAI JIAO TONG UNIV
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