Al4C3 particles form during the primary production of aluminum via molten salt electrolysis due to the carbon solubility and direct contact between bath, metal, and carbon anodes. Additional Al4C3 may form during melt processing through direct contact between the melt and carbonaceous materials. As a result of their small size and similar density to aluminum, removal of aluminum carbide particles can be challenging. If not removed, carbides can produce inclusion defects or poor surface condition in aluminum products. The current work studies the removal and behavior of Al4C3 particles during flotation with different gas mixtures, as well as sedimentation. The interaction between carbide particles and Al2O3 films during the melt treatment processes was also studied and reported. Factsage thermochemical software was used to model the interactions at the interface of inclusions and bubbles covered by films. The highest degree of carbide removal was obtained after flotation with an H2O-containing argon gas mixture, where the carbide concentration dropped below the measured solubility limit of carbon at the corresponding temperature. Strong interaction between Al4C3 particles and Al2O3 films was observed during sedimentation which worked as an efficient removal method for the particles. Oxidation of carbides and formation of oxycarbides were suggested as the mechanisms promoting the attachment of carbides on oxide films.

中文翻译：

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Al4C3 颗粒在铝熔体中浮选和沉淀过程中的行为

由于碳的溶解性以及电解液、金属和碳阳极之间的直接接触，在通过熔盐电解生产铝的初级生产过程中会形成 Al4C3 颗粒。在熔体加工过程中，通过熔体和含碳材料之间的直接接触，可能会形成额外的 Al4C3。由于它们的尺寸小且密度与铝相似，因此去除碳化铝颗粒可能具有挑战性。如果不去除，碳化物会在铝制品中产生夹杂物缺陷或不良的表面状况。目前的工作研究了在不同气体混合物的浮选以及沉淀过程中 Al4C3 颗粒的去除和行为。还研究和报告了熔体处理过程中碳化物颗粒和 Al2O3 薄膜之间的相互作用。Factsage 热化学软件用于模拟薄膜覆盖的夹杂物和气泡界面处的相互作用。用含 H2O 的氩气混合物浮选后获得最高程度的碳化物去除，其中碳化物浓度下降到相应温度下测量的碳溶解度极限以下。在沉淀过程中观察到 Al4C3 颗粒和 Al2O3 薄膜之间的强烈相互作用，这是一种有效的颗粒去除方法。碳化物的氧化和碳氧化物的形成被认为是促进碳化物附着在氧化膜上的机制。其中碳化物浓度下降到相应温度下碳的测量溶解度极限以下。在沉淀过程中观察到 Al4C3 颗粒和 Al2O3 薄膜之间的强烈相互作用，这是一种有效的颗粒去除方法。碳化物的氧化和碳氧化物的形成被认为是促进碳化物附着在氧化膜上的机制。其中碳化物浓度下降到相应温度下碳的测量溶解度极限以下。在沉淀过程中观察到 Al4C3 颗粒和 Al2O3 薄膜之间的强烈相互作用，这是一种有效的颗粒去除方法。碳化物的氧化和碳氧化物的形成被认为是促进碳化物附着在氧化膜上的机制。