銅電解におけるチオ尿素の挙動について

抄録

Some experiments were carried out to examine some behavior of thiourea in electrolytic refining of copper.
Thiourea is stable in pure water but becomes unstable when cupric ions exist and temperature rises. The presence of metallic copper in electrolyte makes thiourea stable.
The amount of thiourea diminishes during electrolysis, and the rate of diminition is proportional to the amount of electric charge flowed.
When the electrolysis is carried out immediately after adding thiourea to the electrolyte, sulfur from thiourea is easily included in electrodeposited copper and the quantity of the included sulfer is proportional to the amount of initially added thiourea. On the other hand, if the electrolysis is started after keeping the electrolyte containing thiourea at 60°C for about 90 hours and making almost all thiourea decompose, very small amount of sulfur is included in the copper, and the property of thiourea to make cathode surfaces smooth is still effective.