File:Transactions (1871) (14577481949).jpg

Identifier: transmining12amer (find matches)
Title: Transactions
Year: 1871 (1870s)
Authors: American Institute of Mining, Metallurgical, and Petroleum Engineers
Subjects: Mineral industries
Publisher: New York (etc.)
Contributing Library: Robarts - University of Toronto
Digitizing Sponsor: University of Toronto

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same quantity ofsmall coal. At some French iron-works from 300 to 400 cwt. of ore isroasted in 24 hours, consuming from 4; to 5J pounds of coal percwt. A Styrian roaster to operate with wood is illustrated in OsbornsMetallurgy^ which consists of a series of circular iron plates or rings,surrounding a central draught-chamber, the latter perforated toadmit air to the mass. The horizontal spaces between the platesfurnish additional air-openings at the periphery, and give access forworking the ore with bars. This is rather an ore-cage than a roast-ing-kiln. A st€am-pipe is also shown as surrounding the base foruse with sulphuret ores. The kiln which seems to meet with most general favor is knownas the Gjers calcining furnace, in the Cleveland district, England.These have a bosh and shell of sheet-iron supported from a mantelresting on columns or brackets and are lined with brick. A cone ofmasonry covered with iron plates is placed at the bottom, and the ROASTING IRON-ORES. 371 Plate I.
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0RE-R0A5TER AT NORWAY FURNACE, BECHTELSVILLE, PA. 372 ROASTING IRON-ORES. furnaces are often provided with iron hoods and chimneys. Amer-ican modifications of these are shown by Plates I, II, III, IV, V. In the larger kilns in the Cleveland districts, the consumption offuel is given at 4 per cent, of the weight of ore. The Gjers kilns are used to a considerable extent in the UnitedStates, probably more so near the Cornwall ore-hills in Pennsyl-vania than in any other single locality, over 90 of these structuresbeing connected with the furnaces which receive all or a part oftheir ore-supplies from the Cornwall ore-hills, the size varying from10 to 22 feet diameter at bosh, and the height from 12 to 20 feet.They are lined with red or fire-brick, and a number are providedwith hoods and chimneys for withdrawing the vapors. In somecases, when a number of roasters are in a nest, a bustle-pipe sur-rounding each kiln is connected with a draught-stack common to all. The kilns roast each from 1

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