Electrolytic separation of metals

Claim 1

A PROCESS FOR SEPARATING A FIRST METAL SELECTED FROM THE GROUP CONSISTING OF GOLD, SILVER AND ALLOYS OF GOLD AND SILVER FROM A COMPOSITE METAL BODY IN WHICH SAID FIRST METAL IS ADHERED AS AN EXTERNAL LAYER OVER A SUBSTRATE CONSITUTED BY A SECOND METAL, THE PROCESS COMPRISING THE STEPS OF: IMMERSING THE BODY IN AN ELECTROLYTIC SOLUTION OF AN ALKALI METAL CYANIDE IN WHICH THE TWO METALS ARE SUBJECT TO DIFFERENTIAL ANODIC DISSOLUTION AT A PREEDETERMIND ANODE VOLTAGE MEASURED BY REFERENCE TO A STANDARD ELECTRODE WITH THE DEGREE OF DISSOLUTION OF THE SECOND METAL IN THE HALF-CELL COMPRISING SAID SECOND METAL AND SAID SOLUTION BEING SUBSTANTIALLY LESS THAN THE DEGREE OF DISSOLUTION OF THE FIRST METAL IN THE HALF-CELL COMPRISING SAID FIRST METAL AND SAID SOLUTION AT SAID VOLTAGE, SUPPLYING DIRECT CURRENT TO SAID BODY FROM THE POSITIVE TERMINAL OF A DIRECT CURRENT POWER SOURCE WHOSE NEGATIVE TERMINAL IS CONNECTED TO A SECOND ELECTRODE IMMERSED IN SAID SOLUTION THEREBY ESTABLISHING AN ELECTROLYTIC CIRUCIT IN WHICH SAID BODY IS THE ANODE AND SAID SECOND ELECTRODE IS THE CATHODE, AND CONTINUOUSLY CONTROLLING THE VOLTAGE OF SAID ANODE RELATIVE TO SAID STANDARD ELECTRODE AT A LEVEL AT WHICH THE DEGREE OF DISSOLUTION OF THE SECOND METAL IN THE HALF-CELL COMPRISING SAID SECOND METAL AND SOLUTION IS SUBSTANTIALLY LESS THAN THE DEGREE OF DISSOLUTION OF THE FIRST METAL IN THE HALF-CELL COMPRISING SAID FIRST METAL AND THE SOLUTION THEREBY CAUSING SELECTIVE REMOVAL OF SAID FIRST METAL FROM SAID BODY.