| 摘要 |
<p>PURPOSE:To prepare a purified soln. for easily and surely producing ultrahigh purity copper by keeping a soln. for electrolytically refining copper contg. ions of nobler metals than copper as impurity ions at a prescribed pH, adding a reducing agent, lowering the electric potential of the soln., depositing and removing the impurity ions. CONSTITUTION:A soln. for electrolytically winning or refining copper contg. ions of nobler metals than copper as impurity ions is adjusted to about pH1-3, a reducing agent such as gaseous hydrogen, hydrazine or formaldehyde is added and the electric potential of the soln. is lowered to about <=40mV. The soln. is then kept at about 25+ or -0.5 deg.C and aged in an atmosphere of a gaseous mixture of Ar with about 3% H2 and the electric potential of the soln. is lowered to the extremely low range of about 310-320mV in which Ag cannot exist as ions. The low electric potential is maintained for a prescribed time and solid matter contg. deposited impurity ions is removed by solid-liq. separation. Ultrahigh purity copper of >=7N grade is obtd. by electrolysis with the resulting purified soln. as an electrolytic soln.</p> |
