非离子型捕收剂作用下的铝电解渣浮选脱碳试验研究

Study on the Flotation Decarbonization of Aluminum Electrolysis Slag under the Action of Non-ionic Collectors

由于铝电解过程中的碳阳极表面发生选择性氧化和不等燃烧,碳颗粒会脱落并形成碳残留物,被称为阳极炭渣。炭渣中含有表面被氧化的石墨碳、有毒杂质、氟化钙(CaF2)、刚玉(α-)和冰晶石(Na)等。对采自贵州某铝业生产过程中产生的铝电解阳极炭渣作为原样进行处理分析,结果表明:经X射线衍射仪(XPS)分析,原样炭渣中碳颗表面存在的主要含氧基团为O1sC=O,含量为45.54%。经激光粒度分析,样品中含有大量的无机矿物质细泥,在浮选过程中这些细颗粒会覆盖在碳颗粒表面,从而进一步降低碳颗粒表面疏水性。据相关研究表明,添加传统捕收剂煤油很难取得理想的碳颗粒回收率,故本研究选择了非离子型表面活性剂油酸、亚油酸甲酯和蓖麻酸作为浮选捕收剂,并与用煤油作为捕收剂结果相比较。浮选结果表明,煤油和蓖麻酸浮选脱碳的最佳用量为1500 g/t,而油酸和亚油酸甲酯的最佳用量为500 g/t,同时,亚油酸甲酯的用量在500 g/t时,浮选效果最佳,精矿回收率和可燃体回收率最大分别为25.70%和73.12%。此外,结合PABI测试表明,亚油酸甲酯能更好地改善铝电解渣中碳颗粒表面疏水性,并与浮选结果相一致。

Due to selective oxidation and unequal combustion on the surface of the carbon anode during the aluminum electrolysis process,carbon particles will break off and form carbon residue,known as anode carbon slag.The carbon slag contains graphitized 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 particles 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,thereby 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 concentrate 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.