高温加水分解によるCu(II)アンミン水溶液からの球形酸化第二銅微粒子の作製

Abstract

The applicability of high temperature hydrolysis method to the precipitation of spherical fine particulates of CuO from aqueous Cu(II) ammine solution was investigated by examining various conditions.Although Cu(II) ammine complexes are stable at ambient room temperature, they are decomposed to CuO by aeration at elvated temperatures, loosing ammonia gas outside the solution system. However, it is impossible to presipitate spherical fine CuO particulates by high-temperature hydrolysis of Cu(II) ammine solution. To obtain spherical fine particles of CuO, it is necessary to remove excess ammonia in the solution by aeration at room temperature, followed by the high temperature hydrolysis without agitation of the solution. The presence of ammonium salts in the solution system is indispensable to obtain sperical particles. The CO2 gas contained in air is useful to form ammonium salt necessary for spherical CuO precipitation. The increases in aging time, ammonia concentration and ammonium salt concentration play an importantrole to increase the resultant CuO particle size. Also, those factors affect undesirably the size distribution of CuO and lower precipitates yield.Anions, such as sulfate and carbonate, do not show distinct effect on spherical CuO precipitation, however carbonate ions show the increasing effect of particle size. On the other hand, chloride ions disturb the formation of spheritical CuO.This method was found to be applicable to leach solution of copper metal with Cu(II) ammine solution to produce spherical fine CuO particulates.