Gaz., 1907-1909); Matte, Recherches sur l'appareil libero-ligneux des Cycadacees (Caen, 1904).
The roasted ore is then smelted to a mixture of copper and iron sulphides, known as copper " matte " or " coarse-metal," which contains little or no arsenic, antimony or silica.
The matte is treated either in reverberatory furnaces (English process), in blast furnaces (German process), or in converters (Bessemer process).
The " American process " or " Pyritic smelting " consists in the direct smelting of raw ores to matte in blast furnaces.
The " Welsh process " closely resembles the English method; the main difference consists in the enrichment of the matte by smelting with the rich copper-bearing slags obtained in subsequent operations.