File:Transactions (1871) (14742812546).jpg

Identifier: transactionsmining56amer (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: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

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Meadt Mld» Mca4il«lli Nci d; Weadi Midi Tails Htoda Tiiilt Heod«Mid«Me«i >W« Pulleif a ■— ^1 i M ^=; h Ftille*Mldtfttu ^ it-40«l5Anacorfdo Rolts tfBttMs 4tllfcll«Mt Julii Hlfc Cumt> Shipping Bin Fig. 7. All these machines are used in the dry process. If fine grinding is necessary to separate the crystals of magnetitefrom the gangue, wet separation is indicated. In this case treatment bysintering, or other processes, to agglomerate the ore is also required.The sintering process solves another difficulty by removing sulphur. Lowiron and high sulphur content are handicaps which can now both be over-come by the combination of magnetic concentration and sintering. S. NORTON AND S. LE FEVRE 901 The accompanying flow sheets of mill No. 3 (Fig. 6), mill No. 4 (Fig,7), and mill No. 5 (Fig. 8), of Witherbee, Sherman & Co. at Mineville,N. Y., show arrangements for treating three different ores. The richnessof the ore determines at what size the first separation can be made.
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Fig. 8. Mill No. 4 has eight sets of rolls instead of six in the other mills, becausethe ore is leaner and requires finer grinding. Wet Magnetic Separation of Cornwall Ore^During the dry magnetic separating tests on Cornwall ore, it becameevident that this process of magnetic separation was not suitable for thisore, for the following reasons: *Test conducted at Colebrook Furnaces, Lackawanna Iron and Steel Co,Lebanon, Pa. Described by B. E. McKechnie. 902 THE MAGNETIC CONCENTRATION OF LOW-GRADE IRON ORES 1. Dust.—The ore must be very dry in order to secure freedom ofmotion between the particles, or poor separation will result. This con-dition allows the very fine particles to escape as dust. No system offans or other arrangements for eliminating or controlhng this dust hasbeen developed which can be successfully operated at a cost not prohibi-tive on this ore. 2. Low Grade of Concentrates.—Owing to the tendency of the fineparticles of talcy gangue to cling to the magnetic pieces,

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