Spherical Copper Fine Powder and Process for Producing the Same

Abstract

Provided is spherical copper fine powder in which the average grain size of copper fine powder is 0.05 μm or more and 0.25 μm or less. Additionally provided is a method of producing spherical copper fine powder including the steps of preparing a slurry by adding cuprous oxide to an aqueous medium containing an additive of natural resin, polysaccharide or a derivative thereof, adding 5 to 50% of an acid aqueous solution to the slurry at a time within 15 minutes, and thereby performing disproportionation. The process enables speedy, efficient and stable production of metallic copper particles controlled in particle shape or particle size, particularly copper fine powder having small particles in size.

1 - 2 . (canceled) 
     
     
         3 . A method of producing spherical copper fine powder, including the steps of preparing a slurry by adding cuprous oxide to an aqueous medium containing an additive of natural resin, polysaccharide or a derivative thereof, adding 5 to 50% of an acid aqueous solution to the slurry at a time within 15 minutes, and thereby performing disproportionation. 
     
     
         4 . The method of producing spherical copper fine powder according to  claim 3 , further including the steps of performing solid-liquid separation and water cleaning to the copper fine powder slurry obtained after the disproportionation, additionally performing alkali solution-based reduction treatment thereto, and repeating the solid-liquid separation and water cleaning of the obtained fine powder slurry to obtain copper powder. 
     
     
         5 . The method of producing spherical copper fine powder according to  claim 4 , wherein acid-based acidification treatment is performed during the course of repeating the solid-liquid separation and water cleaning of the fine powder slurry. 
     
     
         6 . The method of producing spherical copper fine powder according to  claim 5 , further including the steps of filtering the copper powder after the final water cleaning treatment, and additionally performing vacuum drying thereto in order to obtain the copper powder. 
     
     
         7 . The method of producing spherical copper fine powder according to  claim 6 , wherein the average grain size of the copper fine powder is 0.05 μm or more and 0.25 μm or less. 
     
     
         8 . The method of producing spherical copper fine powder according to  claim 7 , wherein the specific surface area (BET) of the copper fine powder is 2.5 m 2 /g or more and 15.0 m 2 /g or less. 
     
     
         9 . The method of producing spherical copper fine powder according to  claim 8 , wherein the average grain size of the copper fine powder is 0.05 μm or more and 0.21 μm or less. 
     
     
         10 . The method of producing spherical copper fine powder according to  claim 4 , further including the steps of filtering the copper powder after the final water cleaning treatment, and additionally performing vacuum drying thereto in order to obtain the copper powder. 
     
     
         11 . The method of producing spherical copper fine powder according to  claim 4 , wherein the average grain size of the copper fine powder is 0.05 μm or more and 0.25 μm or less. 
     
     
         12 . The method of producing spherical copper fine powder according to  claim 4 , wherein the specific surface area (BET) of the copper fine powder is 2.5 m 2 /g or more and 15.0 m 2 /g or less. 
     
     
         13 . The method of producing spherical copper fine powder according to  claim 4 , wherein the average grain size of the copper fine powder is 0.05 μm or more and 0.21 μm or less.