Staged Heap Leaching-direct Electrowinning.
Eisele JA; Elges CH; Wroblewski MD; McClelland GE
1st Int'l Symp Recovery of Precious Metals Freeman Publ San Francisco California 1984 :9 pages
The federal Bureau of Mines, Reno Research Center, is conducting research to develop a staged agglomeration-heap leaching system and to electrowin the dissolved precious metals from the pregnant leaching solution. For direct electrowinning to be successful, the pregnant solutions generated during the initial stages of leaching must be higher grade than obtained by conventional heap leaching. The precious metal concentration of the pregnant solution can be increased by agglomeration pretreatment with cyanide solution that starts the leaching process during the curing period, by leaching with small volumes of solution, and by cycling the leaching solution through more than one heap in a staged manner. The resulting pregnant solution is passed directly through an electrowinning circuit. The barren solution from electrowinning is recycled to the leaching circuit. Bench-scale research on the development of the staged leaching system and on the development of an efficient electrowinning cell is described.
1st Int'l Symp. Recovery of Precious Metals. Freeman Publ., San Francisco, California, 1984, PP.21-29