Study on the Flotation Decarbonization of Aluminum Electrolysis Slag under the Action of Non-ionic Collectors
Due to selective oxidation and unequal combustion on the surface of the carbon anode during the aluminum electrol-ysis process,carbon particles will break off and form carbon residue,known as anode carbon slag.The carbon slag contains graphi-tized carbon with an oxidized surface and toxic impurities such as calcium fluoride(CaF2),corundum(α-Al2O3),and cryolite(NaAl11O17).The XPS analysis results indicate that the main oxygen-containing groups present on the surface of the carbon parti-cles in the raw carbon slag are O1s C=O,with a content of 45.54%.Laser particle size analysis shows that the sample contains a large amount of fine inorganic mineral clay,which can cover the surface of the carbon particles during the flotation process,there-by further reducing the hydrophobicity of the carbon particle surface.Therefore,to recover the carbon particles in the aluminum electrolysis slag through flotation,it is necessary to grind the solid slag into finer particles and add a higher amount of kerosene.To achieve an ideal recovery rate of carbon particles by adding traditional collectors such as kerosene,this study selected non-ionic surfactants oleic acid,methyl linoleate,and ricinoleic acid as flotation collectors.The flotation results show that the optimal dosage of kerosene and ricinoleic acid for decarburization is 1500g/t,while the optimal dosage of oleic acid and methyl linoleate is 500g/t.Moreover,when the dosage of methyl linoleate is 500g/t,the flotation effect is the best,with the maximum recovery rates of concen-trate and combustible matter being 25.70%and 73.12%,respectively.In addition,combined with PABI testing,it is shown that methyl linoleate can better improve the hydrophobicity of the carbon particle surface in the aluminum electrolysis slag,which is consistent with the flotation results.
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