Metalliferous products containing silver arise in many operations; the chief products which may yield silver economically are copper and lead mattes, burnt argentiferous pyrites and certain drosses and scums. Argentiferous ores consist of silver-bearing base-metal minerals and gangue.
With pyritic smelting a sulphuretted copper ore, fed into a cupola in the morning, can be passed directly to the converter, blown up to metal, and shipped as 99% bars by evening - an operation which formerly, with heap roasting of the ore and repeated roasting of the mattes in stalls, would have occupied not less than four months.
18 95, p. 945) has obtained metallic nickel from the Canadian mattes by first roasting them and then eliminating copper by the action of sulphuric acid, the product so obtained being then exposed to the reducing action of producer gas at about 350° C. The reduced metal is then passed into a "volatilizer" and exposed to the action of carbon monoxide at about 80° C., the nickel carbonyl so formed being received in a chamber heated to 180-200° C., where it decomposes, the nickel being deposited and the carbon monoxide returned to the volatilizer.
For an electrolytic method of treating mattes, see T.
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