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Minerals of base metals
Published in Francis P. Gudyanga, Minerals in Africa, 2020
Nickel (Ni) is sufficiently reactive with oxygen which means that elemental nickel rarely exists in nature except in combination with iron thought to be the product of supernova nucleosynthesis [556] such as alloys kamacite and taenite. Limonite ((Fe,Ni)O(OH)), garnierite ((Ni,Mg)3Si2O5(OH)4) which are laterites and pentlandite ((Ni,Fe)9S8), a magnetic sulphide deposit, are the most important commercial sources of nickel. Other minerals in which nickel is found are millerite, nickeline, nickel galena. Like iron, cobalt and gadolinium, nickel is ferromagnetic around room temperature [557] but non-magnetic above its Currie temperature of 355° C [558].
PGM Recovery from Mine Waste
Published in Hossain Md Anawar, Vladimir Strezov, Abhilash, Sustainable and Economic Waste Management, 2019
The UG2 chromite forms part of a series of chromitite layers, traditionally divided into the Lower Group (LG), Middle Group (MG) and Upper Group (UG) chromitites, (Vermaak, 1995). The composition of the UG2 Reef, is relatively consistent throughout the BIC and is rich in chromite, but lacks the Merensky's gold, copper and nickel by-products. However, its reserves may be almost twice those of the Merensky Reef. The principal constituents of UG2 ore are chromitite (60–90%), orthopyroxene, and plagioclase, together with minor amounts of talc, chlorite, and phlogopite, as well as smaller amounts of base-metal and other sulphides and platinum-group minerals (Jones, 1999). The base-metal sulphides are predominantly pentlandite, chalcopyrite, pyrrhotite, pyrite, and to a lesser extent millerite. The sulphide grains of the UG2 Reef ore also generally much finer than those of the Merensky Reef. The PGM content of the Merensky Reef ranges between 4 and 10g/t, whilst that of the UG2 4.4 and 10.6g/t (Jones, 1999). The Platreef is a wider reef with lower PGM values, but higher base metal content.
Advanced Review on Extraction of Nickel from Primary and Secondary Sources
Published in Mineral Processing and Extractive Metallurgy Review, 2019
Pratima Meshram, Banshi Dhar Pandey
Yüce et al. (2007) observed widespread chromite mineralization in the nickel sulfide ore of the Marmara district of Turkey. Some amounts of magnetite and chromite exist in the ore together with sulfide and oxide type nickel minerals. The ore sample contains 1.32% Ni, 10.79% SiO2, 78.39% Fe2O3, 1.3 g/t Ag, and 1.0 g/t Au. The ore sample is constituted of about 70% magnetite, 15% sulfide minerals, and 5% chromite and iron oxides, as well as 10% gangue minerals. Nickel mineralization in the ore such as pentlandite, violarite, millerite awaruite and asbolane was determined. Due to the complex structure of mineralization, a combination of gravity separation and flotation methods was applied for the concentration of nickel sulfide and oxide ores. A nickel concentrate containing 12.32% Ni was produced with 89.7% recovery and final tailings with 0.088% Ni can be disposed with 4.9% of metal loss.
The Direct Leaching of Nickel Sulfide Flotation Concentrates – A Historic and State-of-the-Art Review Part I: Piloted Processes and Commercial Operations
Published in Mineral Processing and Extractive Metallurgy Review, 2023
Nebeal Faris, Mark I. Pownceby, Warren J. Bruckard, Miao Chen
A list of economically important nickel sulfide and arsenide minerals, as well as common sulfidic gangue in nickel sulfide deposits is presented in Table 3. Pentlandite is the most important nickel sulfide mineral and commonly occurs with pyrrhotite and chalcopyrite. Other nickel sulfides listed in Table 3 can be important where alteration has taken place. Violarite is a supergene alteration product of pentlandite and typically occurs in pyrite-violarite and transition zones above the primary zone (massive pentlandite-pyrrhotite ore) (Marston et al. 1981; Nickel, Ross, and Thornber 1974) and can be economically important during the mining of some massive nickel sulfide ores. Millerite forms as an alteration product of pentlandite (Bide, Hetherington, and Gunn 2008; Holwell et al. 2017) and is an important nickel sulfide mineral in some deposits such as Mt Keith, Black Swan and the Otter Shoot, Kambalda (Dowling et al. 2004; Grguric et al. 2007; Keele and Nickel 1974). Niccolite and gersdorffite can occur in nickel sulfide deposits as a result of hydrothermal alteration; their presence in nickel concentrates is undesirable due to the deleterious effects of As during smelting and typically requires dilution to an acceptable level by blending with low As concentrates (Grguric et al. 2007). Pyrrhotite, an iron sulfide, is the primary gangue sulfide that occurs in nickel sulfide deposits though it typically contains Ni, either in solid solution or as fine pentlandite intergrowths (Rezaei et al. 2017; Toguri 1975). Typically, the Ni concentration in solid solution in pyrrhotite is 0.4–0.6% and the presence of micron-size inclusions of pentlandite can raise the nickel content even higher (Rezaei et al. 2017; Toguri 1975). Hence during beneficiation of nickel sulfide deposits, nickel loss due to pyrrhotite rejection is inevitable.
Mineralogical Control on Ash Fusion Temperatures of some High Sulfur Indian coals by oxides generated during combustion
Published in International Journal of Coal Preparation and Utilization, 2023
B. Mahanta, A. Saikia, P. Saikia, J. Jayaramudu, S. Periyar Selvam, A. Varada Rajulu, E. Rotimi Sadiku
Early research has summarized the occurrence and distribution of trace elements in coals (Liu et al. 2013). In this investigation, some of the major (Fe, Ca and Na) trace and heavy elements of environmental concern (As, Cd, Cr, Cu, Pb, Mn, Ni and Mg) present in the raw coals have been estimated through AAS technique (Table 4). Fe is the most dominant element found in all the raw samples. The abundance of Fe in coal is basically related to the Fe-based minerals, such as Pyrite, Hematite and Siderite (Dyk and Waanders 2007). This is supported by the result of the XRD (Fig. 1). Some researchers (Dyk and Waanders 2007; Finkelman 1980, 1995; Goodarzi 2002; Mitchell and Gluskoter 1976) have suggested that Cu may be either shielded by the organic matrix, or may be present as insoluble minerals or as organometallic complexes. Hence, it is found in low quantity in almost all the samples studied. Calcium can be present in multiple modes of occurrence, such as Calcite, Gypsum, Aragonite, Ankertite and so on (Finkelman 1980). So, the presence of Ca in the samples is also supported by the minerals such as Calcite and Gypsum (Table 2 and Fig. 1). Goodarzi (2002) and Swaine (1990) also suggested that Mn can be present in coal as carbonates and is supported by the XRD study. Magnesium in coal mainly occurs in association with Montmorillonite and Ankerite (Goodarzi 2002). The presence of these minerals (Table 2) suggests the availability of Mg in coal. Arsenic (As) in coals mainly occurs with iron disulfides and a minor part is bonded directly in organic matter (Sulovsky 2002). In this study, As is found maximum in Meghalaya samples (B, C). This may be due to high-sulfur content (Table 1). Sodium is also present in the form of sodium chloride in coals (Mitchell and Gluskoter 1976). Hence, a significant concentration of sodium is found in almost all the coal samples. A significant quantity of Ni is also found in Assam coal (A). Ni may be associated with both the organic and inorganic components of coal (Finkelman 1980). It has also been reported that there are some minerals like Millerite (NiS), Linnaeite [(Co, Ni)3S4], etc., which show inorganic association of Ni (Finkelman 1980). However, these minerals are not found in our study which shows the organic association of Ni in our coals. Low quantity of Pb and Cr are also found which have been reported to be found in association with galena and chromite, (Co,Ni)3S4, respectively (Finkelman 1980).