Manganese-bearing minerals

A review of the literature shows that there is a vast amount of crystal field spectral data for iron, the major transition metal in silicate and oxide minerals. The focus of this chapter, therefore, is mainly on ferromagnesian silicates. However, there is also a significant amount of information for chromium-, vanadium- and manganese-bearing minerals. The data are more sporadic for other cations. The optical spectra of the transition metal-bearing minerals enable semi-quantitative estimates to be made of the relative CFSE s of Fe2+, Cr3+, Mn3+, V3+, Ti3+, Ni2+ and Co2+ in many mineral structures. Note, however, that Mn2+ and Fe3+ in high-spin states acquire zero CFSE in oxides and silicates. The crystal field spectra of Mn(II) and Fe(III) minerals are described separately later in the chapter ( 5.10.6 and 5.10.7). 

Oxidation reaction in chemical weathering is important in the case of iron and manganese bearing minerals. 

Similarly to Mn(IV)- and Fe(III)-oxides, some primary minerals were shown to promote polymerization of hydroquinone (19). Olivines, pyroxenes, and amphiboles accelerated the polymerization reaction to a greater extent than micas and feldspars. Microcline and quartz were ineffective- The effect was greatest for tephroite, a manganese-bearing silicate with the ideal chemical formula M SiO. Fayalite, the corresponding Fe(II) analog (Fe2Si0 ), was effective, but to a lesser extent. 

Manning, P. G. (1969a) Absorption spectra of the manganese-bearing chain silicates pyroxmangite, rhodonite, bustamite and serandite. Canad. Mineral., 9,348-57. 

Smith, G., Halenius, U., Annersten, H. Ackermann, L. (1983) Optical and Mossbauer spectra of manganese-bearing phlogopites Fe3+rv-Mn2+VI pair absorption as the origin of reverse pleochroism. Amer. Mineral., 68,759-68. 

Other lithium-bearing minerals are spodumene, a double silicate of lithium and aluminium, containing about 3 8 per cent, of lithium triphyllite, a complex phosphate of lithium, iron, and manganese, with about 2 2 per cent, of lithium and amblygonite and montebrasite, fluo-phosphates of lithium and aluminium, with about 2 35 per cent, of lithium, both rare minerals. 

Kleyenstiiber A. S. E. (1986) The mineralogy of the manganese-bearing Hotazel Formation, of the proterozoic transvaal sequence in Griqualand West, South Africa. In Mineral Deposits of Southern Africa (eds. C. R. Anhaeusser and S. Maske). Geological Society of South Africa, Johannesburg, pp. 257 -272. 

A nickel laterite from Piaui, Brazil was used in this study. The top size of the ore was limited to 12.5 mm. The nickel laterite was composed mainly of quartz, silico-femiginous plasma, and clay minerals. The nickel content is 0.9%. The main nickel-bearing minerals are chlorite, smectite, vermiculite, manganese oxide and silico-ferruginous plasma [6]. Since moisture content, acid concentration, retention time and drum rotation speed are operating factors in drum agglomeration, they were investigated in this study. 

With a relative abundance in the Earth s crust of 122 mg/kg, chromium is the 21st most abundant element and the 6th most abundant transition metal after iron, titanium, manganese, zirconium, and vanadium it is more abundant than nickel, zinc, and copper. Though native chromium is extremely rare (e.g, Udachnaya Mine in Russia), most common chromium-bearing minerals are the spinel-type mineral chromite [FeCr O, cubic] and, to a lesser... 

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