铝电解废槽衬工艺矿物学分析

Mineralogical Analysis of Aluminum Electrolytic Waste Cell Lining

铝电解废槽衬中含较多的有价资源(碳和电解质等),但因其成分复杂、有用矿物紧密共生,回收时存在有用矿物回收率不理想、纯度低、处理成本高等问题,限制了废槽衬的回收利用。采用XRF、XRD、SEM-EDS、MLA等检测手段,对某铝电解废槽衬样品进行完整、详细的工艺矿物学分析。结果表明:废槽衬样品中碳的含量约占67%,此外还含有碳化硅、冰晶石、β-氧化铝、霞石、氟化钠、水碱、树脂及少量非晶态物质。可回收矿物包括碳、氟化钠及冰晶石,其中碳含有较多杂质且内部存在β-氧化铝(NaAl_(7)O_(11))和大量微细粒包裹体,是造成碳回收困难的主要原因;氟化钠主要以颗粒状的形式与微细粒氟化钙紧密共生,使净化电解质的工艺变得复杂;冰晶石则以不规则粒状形式嵌布于碳内部,此外少数冰晶石与氟化钙或氟化钠紧密共生或连生。

Aluminum electrolytic waste cell lining contains many valuable resources(carbon and electrolyte,etc).However,due to its complex composition and close symbiosis between useful minerals,the recovery process of valuable components has the problems of unsatisfactory recovery rate,low purity and high disposal cost,which greatly limit the recycling of waste cell lining.XRF,XRD,SEM-EDS and MLA were used to analyze the complete and detailed process mineralogy of an aluminum electrolytic waste cell lining sample.The results show that carbon content in waste cell lining samples was about 67%,it also contains silicon carbide,cryolite,β-alumina,nepheline,sodium fluoride,alkali,resin and a little amorphous substance.The recyclable minerals include carbon,sodium fluoride and cryolite.The carbon contains more impurities and the presence ofβ-alumina(NaAl_(7)O_(11))and a large number of fine-grained inclusions,which is the main reason for the difficulty of carbon recovery.The purifying electrolytes process is complicated by the close symbiosis of sodium fluoride and fine calcium fluoride in the form of particles.Cryolite is embedded in carbon in irregular granular form,and a few cryolite closely symbiosis with calcium fluoride or sodium fluoride.