青化石灰液中の石灰化合物等不純物の金・銀板の溶解におよぼす影響
1961 年 77 巻 873 号 p. 183-186
詳細
1961 年 77 巻 873 号 p. 183-186
In cyaniding gold ores, Ca-cyanide is used instead of Na-cyanide, because the former is cheaper thanthe latter. But this reagent contains such impurities as sulfer compounds, Ca-compounds, and Na-chloride. Concerning the effects of these impurities, a fundamental reserach was performed by using gold plate and silver one respectively. The silver plate dissolved easily, and the gold one became gradually insoluble with the progress of time in the desulfurized Ca-cyanide solution. Then, using Na-carbonate, we tried to remove the Ca-compounds from the Ca-cyanide solution. These reactions are as follows:
Ca (CN) 2+Na2CO3→CaCO3+2NaCN Ca (OH) 2+Na2CO3→CaCO3+ 2NaOH CaS+ Na2CO3→CaCO3+ Na2S
The cyanide solution composed by the above treatment contains Na-cyanide and Na-chloride. For example, the concentration of Na-chloride in the 0.1% composed cyanide solution was about 0.08%. This composed cyanide solution dissolved much more gold than the ordinary Ca-cyanide solution. The decomposition pct. of cyanide in both of them was almost the same. The Na-chloride added to the ordinary Na-cyanide solution accelerated a little the dissolution of gold plate, while it decreased fairly that of silver plate.
