Nickel pyrites

Cobalt-nickel pyrites, (Fe, Co, Ni)Sa, has been found in Westphalia as small cubic crystals, steel-grey in colour, giving a greyish-black streak.3 Density 4 7, hardness 5 to 5 5. Iron nickel pyrites, (Fe,Ni)S2, occurs in Norway 4 and in the Sudbury district, Ontario.5... 

Roasting of sulfide and sulfate ores (ZnS, pyrites, CU2S, CuCoS, nickel sulfides)... 

The principal direct raw materials used to make sulfuric acid are elemental sulfur, spent (contaminated and diluted) sulfuric acid, and hydrogen sulfide. Elemental sulfur is by far the most widely used. In the past, iron pyrites or related compounds were often used but as of the mid-1990s this type of raw material is not common except in southern Africa, China, Ka2akhstan, Spain, Russia, and Ukraine (96). A large amount of sulfuric acid is also produced as a by-product of nonferrous metal smelting, ie, roasting sulfide ores of copper, lead, molybdenum, nickel, 2inc, or others. 

A U.S. Bureau of Mines survey covering 202 froth flotation plants in the United States showed that 198 million tons of material were treated by flotation in 1960 to recover 20 million tons of concentrates which contained approximately 1 billion in recoverable products. Most of the worlds copper, lead, zinc, molybdenum, and nickel are produced from ores that are concentrated first by flotation. In addition, flotation is commonly used for the recoveiy of fine coal and for the concentration of a wide range of mineral commodities including fluorspar, barite, glass sand, iron oxide, pyrite, manganese ore, clay, feldspar, mica, sponumene, bastnaesite, calcite, garnet, kyanite, and talc. 

Nickel sulfides are very similar to those of cobalt, consisting of NiS2 (pyrites structure, p. 680), Ni3S4 (spinel structure, p. 247), and the black, nickel-deficient Nii-j S (NiAs structure, p. 555), which is precipitated from aqueous... 

Fig. 2.55. Nickel contents of pyrite from the deposits of the Fujimi and Fudotaki groups of the Hitachi mine. Symbols as defined in Fig. 2.54 (Kase and Yamamoto, 1985).

Occurrence. Iron is highly abundant (about 5.5% of the earth s crust) it is believed that the core of earth is mostly molten iron together with nickel. The most common ore is haematite (Fe203). Iron is found in other minerals such as magnetite, limonite, siderite, pyrite. Iron is found native in meteorites known as siderites. 

Nakazawa and Iwasaki (1985) and Pozzo, Malicsi and Iwasaki (1988) investigated a pyrite-pyrrhotite contact and a pyrite-pyrrhotite-grinding media contact on flotation, respectively. They found that the floatability of pyrrhotite increased in the presence of pyrite, whereas it decreased in the presence of both pyrite and grinding media (mild steel). Similarly, a galvanic contact between nickel arsenide and pyrrhotite decreased the floatability of pyrrhotite (Nakazawa and Iwasaki, 1986). 

Nakazawa, H. and Iwasaki, I., 1986. Galvanic contact between nickel arsenide and pyrrlotite and its effects on flotation. Inter. J. Miner. Process, 18 203 - 215 Nakazawa, H. and Iwasaki, 1., 1985. Effect of pyrite-pryyhotite contact on their floatabilities. 

Meyer, F.M., Robb, L.J., OberthOr, T., Saager, R. Stupp, H.D., 1990. Cobalt, nickel, and gold in pyrite from primary gold deposits and Witwatersrand reefs. South African Journal of Geology, 93, 70-82. 

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