On the development of an efficient charcoal for the precipitation of gold and silver from their cyanide solution

Online access for this thesis was created in part with support from the Institute of Museum and Library Services (IMLS) administered by the Nevada State Library, Archives and Public Records through the Library Services and Technology Act (LSTA). To obtain a high quality image or document please contact the DeLaMare Library at https://unr.libanswers.com/ or call: 775-784-6945.That charcoal has the property of precipitating certain metals from their solutions is no new discovery. John Percy (1)* mentions the work done in this connection as early as 1848 by Lasowski and he also gives some results of his own experiments made in 1859, when he precipitated silver from a silver nitrate solution. 3. K. Hose (2) gives Percy the credit of being the first to obtain gold from a gold chloride solution since Percy succeeded in obtaining metallic gold on charcoal from gold chloride in 1869. The first commercial use of the precipitating power of charcoal was in 1880 when W. II. Davis used charcoal to precipitate gold in connection with the chlorination process in a chlorination plant in Carolina. The use of charcoal in chlorination did not become very widespread though it was successfully used at the Mount Morgan Mine, Queensland, Australia. As the cyanide process began to replace the chlorination process it was only natural that charcoal should be given a trial as the precipitant of the precious metals from the cyanide solution, especially since the success of the cyanide process itself depended largely upon the finding of a suitable precipitant. Consequently, in duly, 1894, Dr. W, D. Johnston of San Francisco, California, was granted U. S. Patent number 522,260 for the precipitation of gold and silver from their cyanide solutions by charcoal. Except in special instances charcoal precipitation was not accepted. Shortly after Johnston obtained his patent it was, however, installed at the South German Mine, Maiden, Victoria, Australia, and was successfully operated for several years. Donald Clark (3) has written a more or lose detailed account of operations there. While these operations at Victoria showed that charcoal would do the work, it was not an efficient competitor of zinc because of its bulkiness and consequently practically all cyanide plants favored the zinc