Process for the Extraction of Gold and Silver Remaining in Iron Ores which have already been Treated for the Removal of Sulphur, Copper, or other Metals.

摘要

22,909. Leslie, H. M. Oct. 8. Cyaniding; lixiviating &c.-In a cyanide process for the extraction of gold &c. from the residues of iron ores that have already been treated for the removal of sulphur and copper, the tanks used in the process are provided with covers to prevent the escape into the atmosphere of any hydrocyanic acid liberated, and alkali is supplied to the tanks to combine with the acid. Any volatile cyanogen compounds that may escape are recovered by passing the gases through caustic alkali, as described in Specification 28,235/11. The material is contained in a tank A provided with a filter bottom a, and is washed with liquor from a reservoir B to remove as far as possible all acids or salts that would decompose the cyanide solution. The washing- liquor may be collected in a tank K and returned to the reservoir. The mass is then leached with the solution run from a tank C, protective alkali being supplied from a tank D. Precipitation is effected in a tank G, and the liquor is run to a storage sump H, from whence it may be pumped back into the tank C.