| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1985: ¥700,000 (Direct Cost: ¥700,000)
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| Research Abstract |
The dissolution rates and the solubilities of the following materials in the solution of <NH_4> SCN were examined at various conditions, and the chemical reactions of dissolution of them were deduced. The tested materials were Ag, ZnO, Mn <O_2> , NiO and Co oxide. The main informations from these examinations are follows.
1. Ag is soluble in the concentrated NH SCN solution as Ag thiocyanate complex. Ag dissolves considerable fast, when <Fe^(3+)> or <Cu^(2+)> is added to the solution at pH 2-3 or 8-10, respectively, and oxygen is blowed in to the solution.
2. ZnO dissolves very fast and in high concentration. Dissolved Zn becomes <Zn^(2+)> and Zn thiocyanate complex in the acidic solution, and Zn ammine complex in the alkaline solution.
3. <MnO_2> is soluble in the acidic solution, and dissolves considerably fast at pH 4. <Mn^(4+)> of Mn <O_2> is reduced to <Mn^(2+)> by <SCN^-> and dissolved by acid.
4. CuO is soluble in the concentrated <NH_4> SCN solution and its dissolution is fairly fast. Dissolved Cu becomes Cu thiocyanate complex in the acidic solution, and Cu ammine complex in the alkaline solution.
5. NiO dissolves very slowly. Dissolved Ni becomes Ni thiocyanate complex in the acidic solution and Ni ammine complex in the alkaline solution.
6. <Co_3> <O_4> is soluble only in the acidic solution and its dissolution is very slow. CoO resulted from thermal decomposition of <Co_3> <O_4> dissolves fairly fast.
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