METAL POWDER PRODUCTION BY THE GEL-PRECIPITATION PROCESS

A novel process, termed gel precipitation, has been developed for producing gels of insoluble metallic compounds from aqueous solution. Controlled additions of a solution of the metal, which also contains the dissolved gelling agent, are mixed with a solution of the precipitating reagent, e.g. ammonium hydroxide. The gel is formed by the association of the gelling agent, usually a polymeric organic material, with the phase normally precipitated and in its truest form probably consists of a molecular complex between the organic constituent and the metal compound. The gel forms rapidly on bringing the two solutions into contact and there is no tendency for the discrete particles to adhere or coalesce; all the metal ion is normally confined to the gel phase.The outstanding characteristics of the process are its simplicity and versatility; it operates at normal temperature and requires only conventional chemical plant. It is particularly applicable to precipitating conditions that yield gelatinous pre...