Annual report of the State Mineralogist for the year ending ... . \^i\vWwW^^Aw\J^vkvviUm>UmJ r; i; i ; i; r-c* &e o A. Hearth bottom. B. Iron plate. C. Lead pot. D. Iron beams. E. Forestone. H. Gutter. in the charge has been reduced, the material is scraped out and the slagsseparated from the oxysulphides formed by the operation. The latterare charged once more, with the addition of some lime, fuel, and a fewshovelfuls of ore. The process is thus practically continuous. To betterdivide the blast and prevent a concentration of heat on one point, a brickof peat is placed in front
Annual report of the State Mineralogist for the year ending ... . \^i\vWwW^^Aw\J^vkvviUm>UmJ r; i; i ; i; r-c* &e o A. Hearth bottom. B. Iron plate. C. Lead pot. D. Iron beams. E. Forestone. H. Gutter. in the charge has been reduced, the material is scraped out and the slagsseparated from the oxysulphides formed by the operation. The latterare charged once more, with the addition of some lime, fuel, and a fewshovelfuls of ore. The process is thus practically continuous. To betterdivide the blast and prevent a concentration of heat on one point, a brickof peat is placed in front of the nozzle. The reduced metallic lead grad-ually fills the sump and flows into a lead pot outside, from which it maybe ladled into molds. At the beginning of the operation a thick blacksmoke arises, which soon gives place to a strong current of lead fumes,which is conducted through more or less extensive flues into a rainchamber for the purpose of condensing and recovering it. THE AMERICAN HEARTH This process differs from the one just described, in that a wood fireand hot blast are used, and that pure galena is smelted without previousroasting. LEAD SMELTING. 821 The iron forming the walls of the hearth exerts a desulphurizinginfluence upon the charge. The conduct of this process requires great attention, and the tem-perature must be well regulated, as a too high degree of heat causesvolatilization of lead. When properly conducted, this process gives a good yield of lead andcosts little for fuel and labor. After the hearth has been thoroughly heated by a wood or charcoalfire, the sump is filled with lead bullion. As soon as this is melted some wood is placed before the tuyere, andthe charge introduced, which floats on the lead bath in the sump. Thereduced lead flows out into a receptacle heated by a separate fireplaceto keep the lead fluid until it is poured into molds. The process is a continuous one, as the charge is renewed from timeto time, and a continuous fl
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Keywords: ., bookcentury1800, booksubjectgeology, booksubjectminesandmineralr
