Blast chloride extraction

The residue from the chloridised speiss, after extraction of soluble cobalt and nickel salts, is extracted with sodium thiosulphate, to dissolve out silver chloride, which is recovered as the sulphide and reduced to metal. The residue is dried, ground, and smelted with quartz to remove most of the iron as a slag. This slag is reworked with more ore in the blast-furnaces, as it contains silver and cobalt. The new speiss simultaneoiisly produced is treated as described above for recovering cobalt and nickel, copper, and silver. The final residue is dried, mixed with 20 per cent, of sodium nitrate and 10 per cent, of sodium carbonate, and roasted in reverberatory furnace to convert the arsenic into sodium arsenate, which is extracted with hot water. The dried residue has the following average composition ... 

The potassium chloride can be separated from the insoluble sodium felspar by lixiviation, and from the excess of sodium chloride by fractional crystallization. This process might afford a new method for the manufacture of potassium chloride. It has also been found possible to extract the salt from the dust of the blast-furnace.4... 

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