Pyritic ores containing copper are treated by methods analogous to those of the copper smelter.
In Colorado the pyritic ores containing gold and silver in association with copper are smelted in reverberatory furnaces for regulus, which, when desilverized by Ziervogel's method, leaves a residue containing 20 or 30 oz.
Cornish ores are almost entirely pyritic; and indeed it is from such ores that by far the largest proportion of copper is extracted throughout the world.
The " American process " or " Pyritic smelting " consists in the direct smelting of raw ores to matte in blast furnaces.
Pyritic smelting is a development of the Russian engineer Semenikov's treatment (proposed in 1866) of copper matte in a Bessemer converter.