GB719835A - Improvements in or relating to metal powders - Google Patents

Abstract

Alkali metal addition products of ethers of polyhydric alcohols are formed by mixing the ethers with alkali metal in a subdivided state, preferably dispersed in an inert medium such as liquid aromatic or aliphatic hydrocarbon. The alkali metal is fused and vigorously agitated with the inert medium while maintained at a temperature above the melting-point of the metal. The dispersion, which may contain 20-50 per cent of alkali metal, reacts with the ether at room temperature to give an addition product insoluble in the reaction medium. An ether to metal ratio of 4 : 1 to 10 : 1 is preferred. Suitable ethers are ethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, triethylene glycol methyl ethyl ether, ethylene glycol methyl ethyl ether and ethylene glycol diethyl ether.ALSO:Metal powders are prepared by reduction of metal compounds with an alkali metal addition product of an ether of a polyhydric alcohol such as ethylene glycol dimethyl ether. The preferred metal compounds used are the halides and the use of halides of Fe, Ni, Co, Cr, Mn, Mo, Zn, Cd, Sn and Ag is specifically referred to. Other compounds such as sulphates, nitrates, carbonates, acetates and formates may be reduced. Reference is also made to the production of alloy powders by reduction of mixed compounds e.g. the mixed chlorides of Fe and Ni, Fe and Co or Fe and Cr. The reaction may be carried out by initially forming the alkali metal-ether and then mixing it with the metal compound, preferably using an excess of the alkali metal. Alternatively the metal compound and ether may be mixed and the alkali metal then added as a dispersion in an inert medium such as liquid aromatic or straight chain hydrocarbons.