Production of metallic copper powder by autocatalytic reaction in suspension

The production of metallic powder by precipitation from solution was studied in laboratory scale as an alternative to the conventionally adopted processes, based on the atomization of molten material, for producing metal powders with small particle size. The process is based on the precipitation of metals from aqueous solutions by reduction under controlled conditions. Results of laboratory scale experiments are presented for the production of copper particles from aqueous solutions of copper sulfate, using formaldehyde as reducing reactant, and EDTA as complexing agent. The effect of the presence of nuclei was studied. Metallic particles with average sizes in the range from about 0.3 µm to about 15 µm were obtained. In the process, large particles are formed mainly by aggregation of submicrometric particles, indicating that the particle size distribution of the product depends on the control of particle agglomeration rate.