Patent GB-965574-A (GB)
Title: Process for the production of particulate or sponge-like metals and of shaped articles made therefrom
Inventor: GREBE JOHN JOSEF
IPC: B22F3/00
Filed: 1961-06-23
Abstract: A silicate glass is produced together with finely divided or sponge-like metal which melts above 450 DEG  C. (see Division C7) by heating a mixture of particulate reducible compounds of one or more of the metals, e.g. oxides or sulphides, with a solid reducing agent, preferably carbonaceous, but also including metals such as Na, Ca, K, Li, Mg, Si or metal salts or hydrides, and an inorganic base comprising mainly an oxide, hydroxide or carbonate of an alkali metal, in the presence of an inorganic silicon compound such as silica, with or without materials containing other elements desired in the glass, e.g. oxides of Al and/or Ca, at a temperature below the melting-point of the metal formed and above the softening or melting point of the resulting silicate glass.  The Si required for the glass may be obtained from siliceous ore material, such as haematite or taconite containing siliceous gangue, or Fe-containing slag or fly ash, which together with soft coal or lignite and flake NaOH produce, after heating at 900-1225 DEG  C. in a protective atmosphere, a soft glass-like mass containing dispersed particles of iron.  The hot mass may be worked by rolling or forging to compact the particles into a shaped metal article free from or containing fibres of glass which act as a die lubricant useful in extruding metal products, e.g. for forming glass-coated pipes.ALSO:Finely divided particulate or sponge-like metals, which melt above 450  DEG C. and have standard electrode or oxidation potentials between 1.2 and -0.85 volt, e.g. Fe, Mn, Cr, Te, Co, Ni, Cu, Ag or Sb, are produced together with a silicate glass (see Division C1) by heating a mixture of particulate reducible compounds such as oxides or sulphides of one or more of the above metals with a solid reducing agent, preferably carbonaceous but also including metals such as Na, Ca, K, Li, Mg, Si or metal salts or hydrides, and an inorganic base comprising mainly an oxide, hydroxide or carbonate of an alkali metal such as Li, Na or K, in the presence of an inorganic silicon compound such as silica, with or without materials containing other elements desired in the glass, e.g. oxides of Al and/or Ca, at a temperature below the melting point of the metal formed and above the softening or melting point of the resulting silicate glass. The Si required for the glass may be obtained from siliceous ore material.  For example, with haematite or taconite containing siliceous gangue, or Fe-containing slag or fly ash, the reaction mixture preferably contains 0.05-3 moles SiO2, 1-3 moles carbonaceous reducing agent such as soft coal or lignite and 0.3-4.0 moles alkali metal hydroxide, e.g. flake NaOH, per mole of Fe2O3 content.  After melting in a crucible, the mixture is heated at 900-1225  DEG C. for 1/2 -3 hours in a gas-fired or an electric furnace supplied with a protective atmosphere, e.g. of N2, He or A. The resulting soft glass-like mass containing dispersed particles of iron may be slowly cooled, or shock quenched to produce a fractured mass, and ground, prior to separating the iron particles by magnetic or electrostatic means.  Alternatively, the hot mass, either directly after forming or after reheating, may be worked by rolling or forging to compact the particles into a shaped metal article, either free from or containing fibres of glass which act as a die lubricant useful in extruding metal products, e.g. for forming glass coated pipes.  Other ores specified are chromite, cobaltite, stibnite, manganese ore and pentlandite.