With the fast development and popularization of electronic equipment and new energy industry, the consumption and demands for lithium are on a rapid rise. Spodumene is one of the important lithium resources, so it is of great significance to concentrate it. Beneficiation methods of spodumene include magnetic separation, gravity separation, and flotation. Since the major gangue minerals of spodumene are quartz and feldspar, flotation becomes the most important way to concentrate spodumene. In this paper, various researches related to spodumene flotation were reviewed. It can be seen that the surface properties of spodumene changed with the variation of size fraction, surface dissolution, isomorphous substitution, and grinding method, which means that different spodumene surfaces showed diverse properties. Metal ions such as Fe3+, Ca2+, and Mg2+ can improve and strengthen the flotation behavior of spodumene effectively, when NaOL or NaOL/DDA is used as a collector. The hydroxy complexes of these ions played an important role in the collector adsorption. In the aspect of spodumene collectors, most of the new spodumene collectors reported were mixed collectors; nevertheless, the number of the researches on spodumene collectors was still limited. This review provided a detailed, comprehensive, and valuable reference source for the current research status of spodumene flotation, and provided references for the future researches to improve and strengthen the flotation behavior of spodumene.
Abstract Recent research on Paleo-Tethys tectonics has identified a huge late Paleozoic to Mesozoic igneous belt that extends more than 2500 km in the northeast Tibetan Plateau. However, the magma genesis and evolution in this belt remains a subject of considerable debate. This paper presents a combination of zircon U-Pb ages, mineral compositions, major and trace element concentrations, and Sr-Nd-Hf isotopic data for the plutons across the Zhiduo arc belt that marks the site connecting different tectonic-magmatic units. The studied rocks from one quartz diorite, two granodiorite plutons, and their mafic enclaves define a continuous compositional evolution varying from high- to medium-K calc-alkaline gabbroic diorite to granodiorite. Laser ablation–inductively coupled plasma–mass spectroscopy U-Pb analyses of zircons from these three plutonic suites and one mafic enclave yield Late Triassic ages of 222–217 Ma, establishing that the mafic and felsic magmas were nearly coeval. All these rocks are featured by zoned hornblende and plagioclase with Mg- and Ca-rich mantles or oscillatory change in compositions. They exhibit high and variable MgO (up to 4.88–5.66 wt%), Cr, and Ni contents except that one granitoid pluton (Dangjiangrong) possesses high Co (up to 145.0 ppm). They are characterized by subduction-type trace element patterns, with prominent positive Rb, Th, Pb, and K anomalies and negative Ba, Nb, P, and Ti. Together with continuous and heterogeneous Sr-, Nd-, and zircon Hf-isotopic compositions, it suggests that these Late Triassic high-Mg diorites and associated granitoids were generated through magma mixing and fractional crystallization accompanied by chemical exchange. Taking into account the magmatic record from nearby regions, we suggest that double-sided subduction and rollback of the subducting Paleo-Tethys oceanic slab is the main mechanism to generate geochemically-varied magmatism in the northeast Tibetan Plateau, and eventually close the Paleo-Tethys Ocean during much of the Late Triassic.
Xiasai is the largest magmatic-hydrothermal Ag–Pb–Zn–Sn deposit in the central Yidun Terrane (SW China). Two generations of pyrite are associated with Ag–Pb–Zn mineralization. The coarse-grained pyrite (PyI) occurs together with arsenopyrite and pyrrhotite, and the fine-grained pyrite (PyII) is associated with sphalerite and chalcopyrite. This study documents LA-ICPMS mapping, trace element and LA-MC-ICPMS sulfur isotopic analyses of the two types of pyrite and pyrrhotite, to further constrain the formation of Ag–Pb–Zn veins. Micro-textures reveal that pyrite and pyrrhotite have a homogeneous distribution of trace elements at the individual grain scale, however, some micro-inclusions containing trace elements, including Co, Ni, Cu, Pb, Zn, Ag, Bi, and As, are identified. Pyrite and pyrrhotite are enriched in Co, Ni, Cu, Pb, Zn, Ag, Bi, As, Se, and Sb. However, PyII has higher Cu, Pb, Zn, Ag, and Bi, but lower Co, Ni, As, Sb, and Te concentrations than PyI. The variations of Co and Ni concentrations, as well as the Co/Ni ratios in pyrite and pyrrhotite demonstrate a link with the distance to ore-related granite. PyI has in-situ δ34S values of –6.8 to –3.4 ‰ (average of –5.9 ‰), and PyII exhibits values ranging from –6.7 to –5.4 ‰ (average of –6.0 ‰). Pyrrhotite has δ34S values ranging from –6.9 to –5.5 ‰. The in-situ sulfur isotopic compositions demonstrate a magmatic source for ore-forming materials, which were derived from the Early Cretaceous monzogranite. Trace elements and sulfur isotopic compositions of pyrite and pyrrhotite indicate that the formation of the Ag–Pb–Zn veins at Xiasai is due to a decrease of temperature, salinities, fS2 and fO2 of the hydrothermal fluids.
Abstract The Huaixi copper-gold polymetallic deposit of SE Zhejiang Province, China, is a typical hydrothermal-vein ore body. The Caomen K-feldspar granite porphyry, the dominant intrusion in the mining district, has been dated by laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) analyses of zircon, which yielded a weighted mean 206Pb/238U age of 101.6 ± 0.9 Ma (MSDW = 1.3). Rb-Sr dating of fluid inclusions in auriferous quartz from ore bodies yielded an isochron age of 101 ± 2 Ma. These results indicate that intrusion of the Caomen pluton and Cu-Au mineralization was contemporaneous and corresponds to the third episode of Mesozoic magmatism and metallogenesis in South China. Calculated δ18O values of fluid inclusions from ore-bearing quartz range from −0.89 to −1.98‰ and δD from −42.60 to −60.20‰, suggesting that the ore-forming fluids are derived from a mixed source of magmatic and meteoric waters. δ18S values of 8 pyrites range from −2.14 to +4.14‰ with a mean of +1.67‰, similar to magmatic sulphur. These isotope data support a genetic relationship between the Huaixi copper-gold deposit and the Caomen alkaline granite and probably indicate a common deep source. Petrography and chemical compositions show that the Caomen alkaline granite crystallized from shoshonitic magmas characterized by high SiO2 (75.64–78.00%) and alkali (K2O + Na2O = 7.96–8.82%) but low FeOT (1.34–3.31%), P2O5 (0.05–0.13%) and TiO2 (0.12–0.18%). The granitic rocks are enriched in Ga, Rb, Th, U, and Pb but depleted in Ba, Nb, Sr, P, and Ti. REEs are characterized by marked negative Eu anomalies (Eu/Eu* = 0.06–0.13) and exhibit right-dipping ‘V’ patterns with LREE enrichment. These are similar to the Late Cretaceous alkaline granites in the coastal areas of Zhejiang and Fujian provinces, implying that the Caomen granite formed in a post-collisional extensional tectonic setting. Combined with previous studies, we interpret the Huaixi copper-gold deposit and the associated Caomen alkaline granite as related to back-arc extension due to high-angle subduction of the palaeo-Pacific plate, caused by northward movement of the Indian plate. Keywords: LA–ICP–MS zircon U-Pb datingRb-Sr datingalkaline graniteback-arc extensionHuaixi copper-gold vein depositSE China Acknowledgements This study was financially supported by the Programme for Innovative Research Team in University (IRT0755), the Programmes of Superseding Resources Prospecting in Crisis Mines in China (No. 2006020035 and 2007020047) and the Key Laboratory of Geological Progress and Mineral Resources (GPMR), China University of Geosciences (CUG). We acknowledge the kind help of Mr Roger Mason and Mr Jianwei Li, CUG, for reading through the paper and providing numerous corrections in the usage of English that led to great improvement in the presentation of the paper. Ms Yafei Ge from CUG and Dr Jiajia Zheng from the University of Queensland are acknowledged for their constructive suggestions. We also thank Ms Haihong Chen and Mr Shu Zheng, GPMR, for their analytical support and No. 11 Geological Team of Zhejiang Bureau of Geology and Mineral Resource for their help in the field work.
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