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Show NEW PROCESS FOR EXTRACTING EXTRAC-TING SILVER. The chemistry of Kroncke's method of amalgamating silver ore has been investigated by Louis Eich, says tbe Mining Journal. On treating the liuely-ground red ore with a hot solution solu-tion of chloride of copper and salt, the powder becomes black. Mr. Kieh finds that this arises from the formation forma-tion of sulphide of copper and sulphide of the ore of silver, the antimony being be-ing converted into the chloride and entering en-tering the solution The addition of a second portion of chloride of copper and salt to the precipitated sulphide of silver, in the presence of zinc, reduces re-duces the silver almost immediately to the metallic state. Iu this case the copper again forms a sulphide with the sulphur, in combination with the , silver, thus forming chloride ol' silver, which in its turn parts with its chloride to tho zino. In working this process it is necessary to take care that the so-1 1 lutions of copper and salt are very concentrated, and tho finely-ground ores must bo used dry, as otherwise they could not bo rapidly saturated with tho solutions, and tho basic salts would also be formed. Auotber ditH-cuity ditH-cuity sometimes arises from the precipitation pre-cipitation of copper by the zinc amalgam amal-gam if it bo in excess; when this happens hap-pens Kroucke redissolves it from the pressed amalgam with hot chloride of copper. This process is the ono most commonly employed for treatment ot South American silver ores of tho West Coast. |