Harmless treatment process of electrolytic aluminium scum

A technology for harmless treatment and electrolysis of aluminum, which is used in incinerators, chemical instruments and methods, and the removal of solid wastes. problem, to achieve the effect of harmless treatment

Active Publication Date: 2019-03-29
GANSU DONGXING ALUMINUM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, with the further implementation of the national environmental protection law, the main treatment method for aluminum dross in the industry is stockpiling, but this method causes serious environmental pollution and high stockpiling costs
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Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0024] Example 1

[0025] (1) The electrolytic aluminum scum is crushed to a particle size of 0.1mm by a ball mill, and then a 0.25m filter screen is used to remove impurities. After the removal of impurities, the content of Fe in the electrolytic aluminum scum is 0.25%;

[0026] (2) A mixture of 73% potassium nitrate and 27% sodium chloride is used as a catalyst, and a mixture of 70% cryolite and 30% metallurgical grade alumina is used as a reactant, and the catalyst and reactant are both crushed to the particle size by a ball mill Is 0.1mm;

[0027] (3) The aluminum scum after impurity removal in step (1), the catalyst and reactant in step (2) are transported to the mixer through a conveyor, and a uniform mixture is prepared with a mass ratio of 6: 0.7: 3.3 ;

[0028] (4) The mixture material in step (3) is conveyed to the combustion furnace through a conveyor, and burned at 600°C for 8 minutes to obtain aluminum scum residue ash and combustion flue gas; the carbon content in the a...

Example Embodiment

[0030] Example 2

[0031] (1) The electrolytic aluminum scum is crushed to a particle size of 0.25mm using a ball mill, and then a 0.3m filter screen is used to remove impurities. After the removal of impurities, the Fe content in the electrolytic aluminum scum is 0.27%;

[0032] (2) A mixture of 82% potassium nitrate and 19% sodium chloride is used as a catalyst, and a mixture of 80% cryolite and 20% metallurgical grade alumina is used as the reactant, and the catalyst and reactant are both crushed to the particle size by a ball mill 0.25mm;

[0033] (3) The aluminum scum after impurity removal in step (1), the catalyst and reactant in step (2) are transported to the mixer through a conveyor, and a uniform mixture is prepared at 7:1:3;

[0034] (4) The mixture material in step (3) is conveyed to the combustion furnace through a conveyor, and burned at 760°C for 13 minutes to obtain aluminum scum residue ash and combustion flue gas; the carbon content in the aluminum scum residue ash ...

Example Embodiment

[0036] Example 3

[0037] (1) The electrolytic aluminum scum is crushed to a particle size of 0.2mm by a ball mill, and then a 0.3m filter screen is used to remove impurities. After the removal of impurities, the content of Fe in the electrolytic aluminum scum is 0.29%;

[0038] (2) The mixture of 81% potassium nitrate and 19% sodium chloride is used as the catalyst, and the mixture of 85% cryolite and 15% metallurgical grade alumina is used as the reactant, and the catalyst and reactant are crushed to the particle size by a ball mill Is 0.2mm;

[0039] (3) The aluminum scum after impurity removal in step (1), the catalyst and reactant in step (2) are transported into the mixer through a conveyor, and a uniform mixture is prepared at 8:1.2:0.8;

[0040] (4) The mixture material in step (3) is conveyed to the combustion furnace through a conveyor, and burned at 700°C for 15 minutes to obtain aluminum scum residue ash and combustion flue gas; the carbon content in the aluminum scum resi...

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Abstract

The invention discloses a harmless treatment process of electrolytic aluminium scum and belongs to the technical field of solid waste cyclic utilization in the aluminium electrolysis industry. The harmless treatment process comprises the following steps: aluminium scum after crushing and impurity removal, a catalyst (mixture of nitrate of potash and sodium chloride) and a reactant (mixture of positive cryolite and metallurgical-grade aluminium oxide) are uniformly mixed, and in a combustion furnace, nitrate of potash generates decomposition when burns at 600-760 DEG C to generate combustion-supporting gas namely oxygen so as to enable carbon in the aluminium scum to fully burn; sodium chloride has an accelerating and catalytic action on decomposition of ammonium nitrate category substances; and the metallurgical-grade aluminium oxide can effectively adsorb melted sub cryolite and fluoride salt. With adoption of the harmless treatment process, in burnt aluminium scum residual ash, the carbon content is 3%, and regeneration electrolyte is obtained through molecular ratio adjustment; in burnt exhaust gas, content of fluoride salt is less than 3mg/m3, content of dust particle is less than 20mg/m3, and the burnt aluminium scum residual ash can be directly discharged to the atmosphere after being connected into an aluminium electrolysis exhaust gas purifying system through purification, so that the harmless treatment purpose of electrolytic aluminium scum is realized.

Description

technical field [0001] The invention belongs to the technical field of solid waste recycling in the aluminum electrolysis industry, in particular to a harmless treatment process for electrolytic aluminum dross. technical background [0002] At present, the prebaked anode carbon blocks used in aluminum electrolytic cells are all made of carbon materials kneaded and roasted. During the aluminum electrolysis reaction, due to the inhomogeneity of the carbon material in the anode carbon block, the generation of carbon slag in the liquid aluminum electrolyte is inevitable. The carbon slag floating in the aluminum electrolyte, that is, aluminum dross, will lead to the anode effect of aluminum electrolysis, and at the same time will increase the voltage of the aluminum electrolyte, reduce the current efficiency of aluminum electrolysis, and increase the power consumption per ton of aluminum. [0003] After analysis and research, the main components of aluminum dross are carbon powd...

Claims

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Application Information

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IPC IPC(8): B09B3/00F23G5/00F23G5/033
CPCF23G5/006F23G5/033B09B3/00B09B3/40
Inventor 李振中高峰赵建辉段中波
Owner GANSU DONGXING ALUMINUM
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