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Minerals
Published in W.S. MacKenzie, A.E. Adams, K.H. Brodie, Rocks and Minerals in Thin Section, 2017
W.S. MacKenzie, A.E. Adams, K.H. Brodie
The feldspars are the commonest of the rock forming minerals in the earth’s crust, and comprise two series: the alkali feldspars have compositions between KAlSi3O8 (orthoclase) and NaAlSi3O8 (albite) and the plagioclase feldspars lie between NaAlSi3O8 (albite) and CaAl2Si2O8 (anorthite). Because albite is an end-member of both series the compositions of the feldspars can be represented in a triangle whose corners are these three end members denoted by the abbreviations: Or, Ab and An (Figure 57).
The Zr/Hf ratio as an indicator of granite magma evolution of rare metal deposits related to post-orogenic granites
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
G.P. Zaraisky, A.M. Aksyuk, A.V. Fedkin, R. Seltmann
The rare metal granites described in this paper belong to the intrusive post-orogenic granite-leucogranite series. The main features of the rare-metal granite series are the absence of more basic original varieties than biotite granites (granodiorites and adamellites are rare) and the content and enrichment of rocks by fluorine, rare alkalis (Rb, Cs, Li) and rare metals. The more acidic leucogranites and alaskites with related Sn, W, Mo, Be, Bi mineralization are the latest differentiates of this series in Central Kazakhstan, Middle Asia, Yakutia, North-East of Russia, Eastern Australia, Tasmania and other regions. Differentiation increased in Li-F granites in Eastern Transbaikalia, Primorie (Russia), Erzgebirge-Krusne Hory (Germany-Czech Republic), Cornwall (SW England), Portugal, Central France, Mongolia, Southeastern China, Malaysia and others. Greisen deposits of W, Mo, Sn occur in such regions, but Ta - Nb mineralization related to Li-F albite-amazonite granites and albitites also occurs.
Thermal treatment of K-feldspar for potassium recovery using NaCl–CaCl2 mixture and its mechanism study
Published in Chemical Engineering Communications, 2023
Sandeep Kumar Jena, Sabita Mohapatra, Baijayantimala Mohanty, Ambika Prasad Nayak, Suprabha Palatasingh
Even though the use of CaCl2 extracts nearly 92% potassium, the additive cost and its hygroscopic nature make the process expensive (Haseli et al. 2020). In another attempt, to reduce the process cost, a binary salt mixture of NaCl [melting temperature 801 °C] and CaCl2 [melting temperature 772 °C] has been employed, considering the lower eutectic melting point (∼499–506 °C) of the salt mixture [at 51–68 wt% CaCl2 and 49–32% NaCl] (Myers and Goswami 2016; Xie et al. 2019). Experiments were performed varying the roasting temperature within 480–600 °C and time from 1 to 4 h. The results are provided in Figure 5, showing a maximum of 13% potassium could be extracted at 600 °C after 4 h roasting. This indicates though the melting temperature of the salt mixture was low compared with the individual salts, the K-feldspar structure remains intact. Reports regarding the existence of complete alkali feldspar solid–solution (microcline and albite) above the temperature 600 °C also support the experimental results (Nelson 2011). To evidence the results, XRD pattern of the roast-leached feldspar sample at different temperature ranges (550–750 °C) are provided in Figure 6. For all three cases, it is noticed about the appearance of the same mineral phases as in the feed (Figure 2b), indicating the intactness of the feldspar crystal structure. Thus, further studies, raising the roasting temperature to a higher side, were carried out to disintegrate the feldspar crystal structure for maximum potassium recovery.
Upgrading a Brahmaputra River sand from northern Bangladesh by flotation to produce a high-grade silica glass sand concentrate
Published in Mineral Processing and Extractive Metallurgy, 2022
Md. Aminur Rahman, Kevin J. Davey, Graeme W. Heyes, Warren J. Bruckard, Graham J. Sparrow, Mark I. Pownceby, James Tardio, Md. Nazim Zaman
Quantitative XRD results for the QF−250 µm sample identified quartz (69.4 wt%) as the major mineral followed by feldspar group minerals (29.5 wt%) with a minor amount of mica (1 wt%). The feldspar group minerals identified were albite, orthoclase and microcline. The QF+250 µm sample had a similar mineralogical composition comprising quartz, feldspar and micaceous minerals. Subsequent QXRD results for flotation test products from Tests #1 and #2 with QF−250 µm, where various minerals were concentrated in comparison to their levels in the feed material, resulted in identification of the presence of other minor minerals consistent with the chemical analyses such as apatite (or fluorapatite), hematite, rutile and kaolinite. These were all determined to be present at levels of <0.5–1.0 wt% in the head samples.
Experimental evaluation of sustainable geopolymer mortars developed from loam natural soil
Published in Journal of Asian Architecture and Building Engineering, 2020
Muhammad Ramzan Abdul Karim, Ehsan Ul Haq, Muhammad Asif Hussain, Khurram Imran Khan, Muhammad Nadeem, Muhammad Atif, Arsalan Ul Haq, Muhammad Naveed, Muhammad Mubasher Alam
Albite and anorthite are already present in the natural soil. The peak with increased intensity, in mortars, is due to the formation of new albite/anorthite via geopolymerization reaction and due to increase in the relative amounts of the soil. Haq et al. (Ul Haq, Padmanabhan, and Licciulli 2014) described the presence of albite/anorthite in aluminosilicate source and also in the product after geopolymerization reaction. Albite and anorthite are plagioclase feldspar members which were actually present in the soil due to the hydrothermal history of the soil (Hunt, Mineralogical Society of America, and Kleppa 1994). These are zeolitic phases found in nature hence in natural soils (Itskos et al. 2014). Quartz is the indication of sand, which is present in the soil naturally. Besides these phases, XRD pattern of soil and its respective geopolymers also indicate calcite phase (JCPDS 86–2334) (Ul Haq, Padmanabhan, and Licciulli 2014).