Abstract: A transport duct for carrying abrasive materials, such as ceramic powders. The duct comprises an outer casing and an axially extending array of alternating ceramic and polymer segments each having an interior wall defining a passageway. The transport duct is useful for transporting streams of alumina powder to an aluminum electrolysis cell and for other uses where abrasion resistance and avoidance of internal material buildup are important.

Abstract: An apparatus and method for splitting a mass of fluidizable powder into a plurality of powder streams and conveying the powder streams through a plurality of ducts. The apparatus comprises a powder splitter defining a chamber, a plurality of hollow ducts each having an entrance communicating with the chamber, and a gas source including a plurality of gas nozzles within the ducts and directed outwardly of the chamber. The gas nozzles propel gas jets into the ducts so that portions of the fluidizable powder are conveyed through the ducts. A particularly preferred apparatus is utilized for conveying a plurality of alumina powder streams to an aluminum electrolysis cell.

Abstract: A method for bonding aluminum and aluminum alloys to refractory materials. A body of metal is heated to an elevated temperature at a total pressure above the vapor pressure of aluminum but less than atmospheric pressure. Oxygen partial pressure is maintained sufficiently low to prevent substantial oxidation of the metal. The heated body is contacted with a mass of refractory material and cooled, thereby forming a composite.