Annual report of the State Mineralogist for the year ending ... . Fj£ Fig $7 The furnaces used for roasting measure about forty feet in length byfifteen feet through their widest part. Their exterior shell is made oflava or stone, the interior of firebrick. The ore is dropped from ahopper at the end farthest from the fireplace onto the drying bed, whereit is left for about six hours, being frequently stirred; it is next pushedahead to the desulphurizing bed, somewhat nearer the fireplace, and isallowed to oxidize for six hours more. Lastly, the charge is raked ontothe fluxing bed, being q
Annual report of the State Mineralogist for the year ending ... . Fj£ Fig $7 The furnaces used for roasting measure about forty feet in length byfifteen feet through their widest part. Their exterior shell is made oflava or stone, the interior of firebrick. The ore is dropped from ahopper at the end farthest from the fireplace onto the drying bed, whereit is left for about six hours, being frequently stirred; it is next pushedahead to the desulphurizing bed, somewhat nearer the fireplace, and isallowed to oxidize for six hours more. Lastly, the charge is raked ontothe fluxing bed, being quite near the fireplace and a few inches below thelevel of the other two beds. After the lapse of still another period ofsix hours, the mixture has become thoroughly fused, and is a charge is moved ahead a step, another one is dropped onthe drying bed. Working thus continuously, eight tons of charge areroasted and fluxed in the course of twenty-four hours, requiring the con-sumption of about two tons of coal. For fluxing, 6 per cent of lime and7 per c
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Keywords: ., bookcentury1800, booksubjectgeology, booksubjectminesandmineralr
