Treatment method for decontaminating chromic slag by utilizing eutrophicated algal residue

A technology of eutrophication and treatment method, which is applied in the treatment field of using eutrophic algae residues to make harmless chromium residues, can solve problems such as high cost, and achieve the effects of reducing raw material costs, reducing investment costs, and simple equipment

Inactive Publication Date: 2010-12-01
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

After the lake sediment and chromium slag are evenly mixed, they are placed in a microwave field for oxidation-reduction reaction, and the hexavalent chromium

Method used

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  • Treatment method for decontaminating chromic slag by utilizing eutrophicated algal residue
  • Treatment method for decontaminating chromic slag by utilizing eutrophicated algal residue

Examples

Experimental program
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Example Embodiment

[0025] Example 1

[0026] Add iron trichloride or lime polyaluminum to the algae residue to dehydrate it to 75%, grind the chromium residue to a 2mm screen, mix it with the algae residue at a mass ratio of 1:10, and stabilize for 5 hours. The mixture is fed into the inner tube of the external heating type rotary kiln through the screw feeder for preheating and drying, and the residence time of the mixture in the inner tube of the external heating type rotary kiln is 0.5 hours, so that the moisture content of the dried mixture is less than 5%.

[0027] The reduction combustion furnace uses natural gas as fuel, and controls the excess air coefficient in the reduction combustion furnace to 0.9. The generated hot gas temperature is about 500°C and the oxygen content is less than 0.5%. The high temperature hot gas generated is introduced into the internal heating pyrolysis furnace.

[0028] The mixture preheated by the external heating type rotary furnace is sent to the internal heating t...

Example Embodiment

[0032] Example 2

[0033] Add ferric chloride or lime polyaluminum to the algae residue to dehydrate it to 80%, grind the chromium residue to a 2mm screen, mix with the algae residue at a mass ratio of 1:10, and stabilize for 1 hour. The residence time in the inner cylinder of the external heating type rotary furnace is 0.5 hours, so that the moisture content of the dried mixture is lower than 5%.

[0034] The reduction combustion furnace uses natural gas as fuel, controls the Ono air surplus coefficient in the reduction combustion furnace to 0.8, produces hot gas temperature of about 500℃, oxygen content <0.5%, and produces high temperature hot gas into the internal heating pyrolysis furnace.

[0035] The mixture preheated by the external heating type rotary furnace is sent to the internal heating type pyrolysis furnace, and it is directly contacted with high temperature hot gas with a temperature of about 500 ℃ under oxygen-free or oxygen-deficient conditions for pyrolysis treatmen...

Example Embodiment

[0039] Example 3

[0040] Add iron trichloride or lime polyaluminum to the algae residue to dehydrate it to 80%, grind the chromium residue to a 2mm screen, mix with the algae residue at a mass ratio of 1:10, and stabilize for 2.5 hours. After the chromium residue is ground to a 2mm screen, it is mixed with the algae residue at a mass ratio of 1:10, and the mixture is sent to the inner cylinder of the external heating rotary furnace through the screw feeder for preheating and drying, and the mixture is in the inner cylinder of the external heating rotary furnace The residence time is 0.5 hours, so that the moisture content of the dried mixture is less than 5%.

[0041] The reduction combustion furnace uses natural gas as fuel, controls the excess air coefficient in the reduction combustion furnace to 0.8, produces hot gas temperature of about 450°C, and oxygen content <0.5%. The high temperature hot gas generated is introduced into the internal heating pyrolysis furnace.

[0042] Th...

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Abstract

The invention relates to a treatment method for decontaminating chromic slag by utilizing eutrophicated algal residue in the technical field of environmental protection. The treatment method comprises the following steps of: with algal residue as an additive, mixing the chromic slag and the algal residue according to a certain ratio; conveying the mixture into an externally heated rotary furnace for drying; then, conveying in an internally heated pyrolyzing furnace for a pyrolytic reaction; introducing high-temperature hot reaction gas in the internally heated pyrolyzing furnace from a reaction combustion furnace; cooling and discharging a pyrolytic product after reaction treatment; and mixing tail gas of the internally heated pyrolyzing furnace with air through a diluted tank and then enabling the mixture to enter the externally heated rotary furnace to indirectly dry the mixture of sediment and the chromic slag. The invention has the advantages of simple process flow, low investment cost, easily obtained additive raw materials and satisfactory reaction effect and can effectively realize the optimal utilization of values generated by the eutrophication of lakes while detoxifying the chromic slag.

Description

technical field [0001] The invention relates to a method for harmless treatment of chromium residue in the technical field of environmental protection, in particular to a method for harmless treatment of chromium residue by using eutrophic algae residue. Background technique [0002] As the problem of eutrophication in lakes, rivers and other water bodies in my country is becoming more and more serious, the frequent outbreaks of algae blooms have brought a great impact on people's lives. tens of millions. Subsequent disposal of algae residue has also become a major problem that cannot wait to be solved. The moisture content of algae residue is generally 95% to 97%, and its main components are algae, and there are also protozoa and their corpses, as well as other organic debris, inorganic ions, hydroxide flocs and so on. The pollutant concentration of algal residue is related to environmental factors (raw water turbidity, sunshine, water temperature, etc.), slag discharge cy...

Claims

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Application Information

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IPC IPC(8): A62D3/37A62D3/40A62D101/43
Inventor 张大磊董阳孔海南李春杰何圣兵巫娟
Owner SHANGHAI JIAO TONG UNIV
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