Process for the recovery of gold and/or silver and possibly bismuth contained in sulfuretted ores and/or sulfoarsenides

Claim 1

In a process for recovering gold and/or silver and possibly bismuth contained in a sulfuretted ore and/or sulfoarsenide, said ore, from which is gangue has been removed according to known processes, is treated according to the following successive operations: a reducing roasting; an oxidising roasting; a possible crushing; a first lixiviation by a sulfuric acid solution containing about 20 to 120 g of acid per liter, at a temperature of about 20° to 85° C. and for a duration of 0.5 to 3 hrs.; after separation of the solid, a lixiviation of said solid effected with the aid of a sulfuric acid thiourea solution containing from 10 to 50 g/l of thiourea, at a pH of 0.7 to 1.5, at a temperature of 20° to 70° C., for a duration of 15 mins. to 15 hrs., this lixiviation being conducted so that the potential of oxidoreduction of the medium is maintained at a value of between about 100 and about 180 mV; and, after filtration of the solution, a cementation of said solution to recover the gold, silver and bismuth that it contains.