METHOD OF PRECIOUS METALS EXTRACTION FROM ORES Russian patent published in 1998 - IPC

FIELD: hydrometallurgy of precious metals. SUBSTANCE: quartz ore concentrate containing 14.4 g/t gold, 51 g/t silver is treated with solution containing 100 g/dm³ iron chloride, 100 g/dm³ sodium chloride, 0.8 mole/dm³ sulfuric acid and 0.5 cm³ sodium nitrite at concentration 5 mole/dm³. Leaching is carried out for 28 h at ratio solid : liquid = 1-4 at batch sodium nitrite addition. Residual gold content in cake is 4.25 g/t and silver - 3.33 g/t that corresponds the extraction degree 70.5 and 93.5%, respectively. Process is carried out at the room temperature without reagent change during leaching. Method can be used for secondary raw processing and provides simultaneous gold and silver extraction. EFFECT: simplified process, decreased reagent consumption. 1 tbl