Merrill Crowe

Refining Gold: Remove Zinc by Distillation

It seems desirable to remove zinc more completely than can be done by acid-treatment, and also to obtain it in a form at once available for precipitation again. I feel safe in saying that from 40 to 50 per cent, of the zinc originally used for precipitation could be thus recovered. Philip Argall says, in … Read more

Refining Zinc Precipitates: Cyanide Leaching of Gold & Silver Extraction

Attempts to discover, for the cyanide process, a better precipitant than zinc have been unsuccessful. Hydrogen sulphide, sulphurous acid, ferrous sulphate, etc., precipitate gold and silver from cyanide solutions either not all or incompletely. Aluminum has been tried, but it costs too much, and cannot be used in solutions containing lime. Charcoal has been used … Read more

Assaying Zinc Box Residues in Cyanide Leach Process

Several methods, both wet and dry, for the assay of zinc-box residues from the cyanide process, have been described in recent years, and each of them has been claimed to be superior to all others. A paper, entitled “Assay of Zinc Precipitates,” was published in the School of Mines Quarterly to the purport that the … Read more