OCR Text |
Show Cyanide Proposition. The most universally used means of precipitating gold tfrom cyanide solutions Is by means of threads of zinc. In-a fow words, tho gold solution 1 run through charcoal ill tors, which collect the gold, which when woll churged with the precious pre-cious metal is dried and Incinerated in a furnace of proper construction, says Ores and MetalP, Denver. It has been found In practice that a series of charcoal filters afford the most satisfactory results, a slnglo ono rarely recovering more than 25 per cent of tJie gold. Charcoal Is successfully success-fully employed to precipitate gold from chlorine solutions. Iron sulphate Is also used for this purpose. Sulphuretted hydrogen hy-drogen will precipitate gold from both bromtno and chlorine solutions containing it. Mercuric chloride will precipitate gold from gold solutions of cyanldo, and action Is facilitated by heating the solution, but It is limited in its usefulness, as In tho prosenco of free potassium cyanldo no precipitation of gold occurs. |