Having refractory ore under treatment, it is generally the case that copper is also found in it. While roasting, the presence of copper is favorable for the chlorination of the silver, but copper ores require some more salt, especially if it is intended to save the copper also. The more chloride of copper formed, the more will be found in the solution while leaching it with hot water. In order to convert all the copper into a chloride, it would take at least one and a half pounds of salt to each pound of copper; and considering other base metals, lime, etc., all of which absorb chlorine, while a considerable part escapes useless, the above quantity has to be doubled. For this reason no special attention can be paid to the copper ; only that part of it can be extracted which is converted into a chloride during roasting under the usual circumstances. The chloride of copper transfers a part of its chlorine to the silver and other metals (23), and is reduced thereby to a sub-chloride ; if there is sufficient salt in the furnace it is raised again to a chloride. This sub-chloride (Cu2 Cl) is not soluble … Continue reading Precipitation of Copper contained Silver leached out with Copper