METODO PER ALLONTANARE PARTICELLE SOSPESE DA METALLI FUSI, IN PARTICOLARE ALLUMINIO O MAGNESIO

摘要

Molten metal such as the light metals aluminum and magnesium containing finely divided suspended particles is treated to remove such particles and beneficiate the metal. The particles are typically in the micron size range and may include solid material such as oxides or solid salt particles and may include buoyant liquid particles such as liquid salt particles. Solid particles may be attached to or encapsulated within liquid salt particles. The molten metal containing the suspended particles is moved through a medium of submerged contacting surfaces such as a packed bed. The contacting medium has a high void fraction and a high specific surface area. This results in coalescence or agglomeration of the particles which are thus rendered more responsive to gravity separation than the fine particles. The molten metal preferably is then passed through inclined channels or passages in contact with inclined surfaces such as parallel plates or tubes, the movement therethrough being substantially laminar. Buoyant particles and agglomerates collect on the underside of the inclined surfaces and typically move upwardly in counterflow relationship with metal where the metal moves laterally and downwardly through the inclined passages. A plurality of such inclined surfaces may be provided as tubes or parallel plates. A gas such as a nonreactive gas with or without a chlorinaceous or halogenaceous gas may be bubbled through the contacting medium for further treatment of the molten metal. Such gas can be used to provide a mild disturbance in the contacting medium to aid removal of agglomerated particles, especially buoyant particles, therefrom.