Minerals ferromagnetic

Another physical separation process makes use of the magnetic properties of certain minerals. Ferromagnetic metals are strongly attracted to magnets. The mineral... 

The mixed valent oxide Mn.O occurs in nature as the mineral hasumannite. The stmcture of this ferromagnetic material has been the subject of much dispute. Mn.O is the most stable of the manganese oxides, and is formed when any of the other oxides or hydroxides are heated in air above 940—1000°C. The oxidation of aqueous solutions of Mn (OH)2 can also lead to the formation of Mn O. ... 

Magnetic Pulleys. Magnetic puUeys of special design are used in the concentration of magnetite and other ferromagnetic minerals. For best results, the feed should be screened into various-sized fractions and each fraction treated on a separate puUey separator unit. Typical feed size is 100 X 50 mm, 50 x 25 mm, and 25 x 6 mm. When treating material of —10 mm, an axial pole magnetic puUey should be utilized, as this provides uniformity of field across its width. 

Six sulphide species were observed in the non-ferromagnetic heavy mineral concentrates (NFM-HMCs) of bedrock samples arsenopyrite pyrite > chalcopyrite > bismuthinite = molybdenite = cobaltite. Chalcopyrite, pyrite and bismuthinite do survive in near-surface till but only in minor amounts (<8 grains/sample). Although the Co-rich composition of arsenopyrite is possibly the strongest vector to Au-rich polymetallic mineralization in the study area, sandsized arsenopyrite is absent in C-horizon tills, suggesting that arsenopyrite more readily oxidizes than chalcopyrite and pyrite in till, and therefore is an impractical indicator mineral to detect mineralization using surficial sediments at NICO. 

Nickel is a silver-white, lustrous, hard, malleable, ductile, ferromagnetic metal that is relatively resistant to corrosion and is a fair conductor of heat and electricity. Nickel is a ubiquitous trace metal that occurs in soil, water, air, and in the biosphere. The average content in the earth s crust is about 0.008%. Nickel ore deposits are accumulations of nickel sulfide minerals (mostly pentlandite) and laterites. Nickel exists in five major forms elemental nickel and its alloys inorganic, water-soluble compounds (e.g., nickel chloride, nickel sulfate, and nickel nitrate) inorganic, water-insoluble compounds (e.g., nickel carbonate, nickel sulfide, and nickel oxide) organic, water-insoluble compounds and nickel carbonyl Ni(CO). ... 

Discussion and Conclusion The chemical composition of iron oxides is useful to discriminate a range of mineral deposit types. Discriminant diagrams can be used to identify potential for specific mineral deposit types to occur in an area that has been glacially eroded using till. In this study, a small subset of the ferromagnetic fraction (50 grains, 0.5-1.0 mm size fraction) of a till has been shown to adequately display the compositional... 

The present authors proposed ferromagnetic supports, which can withstand liquefaction environment and conditions by their inherent nature or by protection with a carbon coating (141). Carbon has been recognized as an excellent support for FeS and Ni-MoS as described in the previous section (50). Very fine particles of ferrite are available. Coating with carbon can be performed through precipitation of polymers or pitches by the aid of suspension agents followed by carbonization (Ml). Catalyst deactivation by mineral and carbon deposition should be avoided for this approach to be feasible. 

Figure 11. Proposed mechanism to account for ferromagnetic coupling in mixed-valent nontronite Exchanged electrons are indicated by enclosure in either a circle or rectangle (Reproduced with permission from Ref 33. Copyright 1987 The Clay Minerals Society).

---