Synthesis of fine oxide particles by high temperature hydrolysis of aqueous metal ammine solution

High temperature hydrolysis of the mixed aqueous solution consisting of 5.0 x 10(-3)similar to 5.0 x 10(-2) kmol.m(-3) Cu(II), Zn(II), Co(II) or Ni(II ) sulfate, 0 similar to 0.5 kmol.m(-3) (NH4) 2SO4 and 0.1 similar to 1.2 km ol.m(-3) NH3 were studied at 373 K for 3.6 ks to examine the effects of sol ution composition on the shape, particle size and precipitation degree of t he hydrolyzed particles. Particles precipitated were identified as spherica l CuO, cylinder shape ZnO, spherical Ni(OH)(2) and spherical Co3O4 The increase in the concentration of metal ions, NH3 and (NH4)(2)SO4 in the high temperature hydrolyses of Cu(Il) and Zn(II) results in the increase o f particle size, while the precipitation degree decreases. In contrast, the increase in the concentration of Co(II) ions results in a slight increase in the particle size, but there was no significant effect on controlling pa rticle size expected from changing NH3 and (NH4) 2SO4 concentrations. As mentioned above, the particle shape as well as the particle size can be controlled by changing the composition of ammine solution in the case of Cu (II) and Zn(II), whereas it is difficult for Co(II). The control of particl e size of Cu(II) is far easier than that of Zn(II). The change in precipita tion degree by changing the solution composition was the smallest with Cu(I I). Controlling the particle size of Co3O4 was almost impossible by changin g solution composition.