Enhanced Flotation Separation of Cassiterite from Calcite Using Metal-Inorganic Complex Depressant

At present, the research on flotation separation of cassiterite and gangue minerals is mainly focused on the development of new collectors or depressants, while the research on combined depressants is rare. In this study, the flotation separation of cassiterite and the typical gangue mineral, calcite, was investigated using the metal-inorganic complex depressant AlSS, composed of aluminum sulfate (Al2(SO4)3) and water glass (Na2SiO3·4H2O). The flotation results indicated that, with the assistance of Al3+, the inhibition effect of SS (water glass) on calcite is significantly enhanced, while the inhibition effect on cassiterite is almost unchanged. The zeta potential and adsorption measurements proved that the formation of the negatively charged colloidal particles composed of Alm(OH)n3m−n and SiOm(OH)n4−2m−n tended to adsorb on the positively charged calcite surface, inhibiting the adsorption of sodium oleate (NaOL), while the adsorption of the colloidal particles on the negatively charged cassiterite surface is relatively less. The contact angle measurements indicate that the contact angle of cassiterite in the NaOL + AlSS solution is obviously larger than that of calcite, which indicates that cassiterite has better floatability in this system. The X-ray photoelectron spectroscopy (XPS) analysis confirms the Al and Si species are adsorbed on the surface of calcite, but not on the cassiterite. In addition, the adsorption of AlSS on cassiterite and calcite changes the chemical environment on the calcite surface, indicating that the adsorption of AlSS on the mineral surface is more inclined to be through a chemical reaction.

Magmatic-Hydrothermal Mineralization Processes at the Yidong Tin Deposit, South China: Insights from In Situ Chemical and Boron Isotope Changes of Tourmaline

Owing to the superimposition of water-rock interaction and external fluids, magmatic source signatures of ore-forming fluids for vein-type tin deposits are commonly overprinted. Hence, there is uncertainty regarding the involvement of magmatic fluids in mineralization processes within these deposits. Tourmaline is a common gangue mineral in Sn deposits and can crystallize from both the magmas and the hydrothermal fluids. We have therefore undertaken an in situ major, trace element, and B isotope study of tourmaline from the Yidong Sn deposit in South China to study the transition from late magmatic to hydrothermal mineralization. Six tourmaline types were identified: (1) early tourmaline (Tur-OE) and (2) late tourmaline (Tur-OL) in tourmaline-quartz orbicules from the Pingying granite, (3) early tourmaline (Tur-DE) and (4) late tourmaline (Tur-DL) in tourmaline-quartz dikelets in the granite, and (5 and 6) core (Tur-OC) and rim (Tur-OR), respectively of hydrothermal tourmaline from the Sn ores. Most of the tourmaline types belong to the alkali group and the schorl-dravite solid-solution series, but the different generations of magmatic and hydrothermal tourmaline are geochemically distinct. Key differences include the hundredfold enrichment of Sn in hydrothermal tourmaline compared to magmatic tourmaline, which indicates that hydrothermal fluids exsolving from the magma were highly enriched in Sn. Tourmaline from the Sn ores is enriched in Fe3+ compared to the hydrothermal tourmaline from the granite and displays trends of decreasing Al and increasing Fe content from core to rim, relating to the exchange vector Fe3+Al–1. This reflects oxidation of fluids during the interaction between hydrothermal fluids and the mafic-ultramafic wall rocks, which led to precipitation of cassiterite. The hydrothermal tourmaline has slightly higher δ11B values than the magmatic tourmaline (which reflects the metasedimentary source for the granite), but overall, the tourmaline from the ores has δ11B values similar to those from the granite, implying a magmatic origin for the ore-forming fluids. We identify five stages in the magmatic-hydrothermal evolution of the system that led to formation of the Sn ores in the Yidong deposit based on chemical and boron isotope changes of tourmaline: (1) emplacement of a B-rich, S-type granitic magma, (2) separation of an immiscible B-rich melt, (3) exsolution of an Sn-rich, reduced hydrothermal fluid, (4) migration of fluid into the country rocks, and (5) acid-consuming reactions with the surrounding mafic-ultramafic rocks and oxidation of the fluid, leading to cassiterite precipitation.

Tungsten Ores of the Dzhida W-Mo Ore Field (Southwestern Transbaikalia, Russia): Mineral Composition and Physical-Chemical Conditions of Formation

This article discusses the peculiarities of mineral composition and a fluid inclusions (FIs further in the text) study of the Kholtoson W and Inkur W deposits located within the Dzhida W-Mo ore field (Southwestern Transbaikalia, Russia). The Mo mineralization spatially coincides with the apical part of the Pervomaisky stock (Pervomaisky deposit), and the W mineralization forms numerous quartz veins in the western part of the ore field (Kholtoson vein deposit) and the stockwork in the central part (Inkur stockwork deposit). The ore mineral composition is similar at both deposits. Quartz is the main gangue mineral; there are also present muscovite, K-feldspar, and carbonates. The main ore mineral of both deposits is hubnerite. In addition to hubnerite, at both deposits, more than 20 mineral species were identified; they include sulfides (pyrite, chalcopyrite, galena, sphalerite, bornite, etc.), sulfosalts (tetrahedrite, aikinite, stannite, etc.), oxides (scheelite, cassiterite), and tellurides (hessite). The results of mineralogical and fluid inclusions studies allowed us to conclude that the Inkur W and the Kholtoson W deposits were formed by the same hydrothermal fluids, related to the same ore-forming system. For both deposits, the fluid inclusion homogenization temperatures varied within the range ~195–344 °C. The presence of cogenetic liquid- and vapor-dominated inclusions in the quartz from the ores of the Kholtoson deposit allowed us to estimate the true temperature range of mineral formation as 413–350 °C. Ore deposition occurred under similar physical-chemical conditions, differing only in pressures of mineral formation. The main factors of hubnerite deposition from hydrothermal fluids were decreases in temperature.

Talc Flotation—An Overview

Talc is a naturally hydrophobic gangue mineral in most sulfide ores. However, talc has vast applications in the cosmetics, paper, and paint industries due to its high chemical stability, and its demand continues to grow. Since flotation is the most effective beneficiation technique for upgrading sulfides, the high hydrophobicity of talc has made its selective separation challenging. This paper explored the different properties of talc and the different factors that affect its flotation separation performance as a proven versatile beneficiation technique. Surface properties, zeta potential measurements, contact angles, and other factors affecting the talc flotation efficiency were discussed in detail. It was observed that the surface face/edge ratio (particle size) has a direct relationship with the level of talc hydrophobicity. Talc surfaces are negatively charged in a wide pH range (pH 2–12). Different depressants have already been studied; however, most of them showed low selectivity. The addition of ions such as Ca2+ could enhance talc depression. Pretreatment methods such as ultrasonic and thermal treatments were reported to decrease the talc floatability. It was demonstrated that the development of new selective depressants or pretreatment options for talc flotation requires attention in future investigations to improve its selective separation.

Flotation Separation of Chalcopyrite and Talc Using Calcium Ions and Calcium Lignosulfonate as a Combined Depressant

As a major gangue mineral in sulfide ores, talc is difficult to separate from chalcopyrite in the flotation process due to its natural floatability, which affects the subsequent smelting process. In this study, the effects of calcium ions and calcium lignosulfonate (CLS) as a combination depressant for talc were systematically investigated along with the fundamental mechanisms. The results of our flotation tests showed the talc floating can be effectively depressed via the combination depressant effect of calcium ions and CLS over the pH range of 6–12. Measurements of the adsorption capacity, zeta potential, and Fourier transform infrared (FTIR) showed an enhancement of the adsorption capacity and adsorption strength of CLS on the talc surface after calcium ions were added. This result indicates that calcium ions adsorbed onto the talc, neutralized the negative charge on the surface of talc, generated the binding site with CLS, and formed the [talc-Ca2+/Ca(OH)+-CLS] system by strong adsorption. Further, the coverage rate of CLS on talc was significantly improved after the addition of calcium ions, as shown in the AFM imaging.

Preliminary investigation for beneficiation of Indonesian manganese ore

n this study, manganese ore sample collected from Palludda village, Barru Regency, South Sulawesi Province, Indonesia was investigated. Processing is required to make the ore viable and profitable. The focus of this study is determining the distribution of the assay values among various sizes of manganese ore. On the other hand, to obtain information about its optimum size, which contains the main mineral in a large portion with a small portion of the gangue which consisted in the manganese ore, which defined as the liberation of its main mineral from the gangue. Size assay analysis of manganese ore is of prime importance through which much information can be obtained. The fractioning and chemical analysis are conducted to measure the assay of various minerals and also their distribution in different size fractions. It indicated that manganese and hematite are valuable mineral present, whereas Pb and Zn are the trace element compositions and the gangue mineral that present in the ore is silica. Based on the assay value of each size fraction of manganese ore showed that the maximum liberation of manganese mineral could be obtained at the size range of -20 to +48 mesh. Therefore, further investigation studies on this manganese ore are needed.

Influence of Mineralogy on the Dry Magnetic Separation of Ferruginous Manganese Ore—A Comparative Study

Magnetic separation is often considered pertinent for manganese ore beneficiation when the ore is abundant with siliceous rich gangue mineral phases. However, the process is deemed to be inapposite for the ferruginous type of ore, and remains a grey area of research. In the present investigation, two different types of manganese ore were studied in detail to understand the influence of mineralogy on their magnetic separation performance. Detailed experiments were performed by varying the critical variables of the dry magnetic separator, and the separation features were studied. The ore samples were thoroughly characterized by various techniques, including an automated advanced mineralogical tool. The mineralogical results revealed that primary manganese bearing minerals in both the ores are rich in cryptomelene, pyrolusite, psilomelane, and bixybyite. Similarly, the major gangue minerals were alumina-bearing minerals and iron-bearing phases (hematite and goethite). The optimum grade that could be obtained from single-stage dry magnetic separation was 35.52% Mn, and with a Mn:Fe ratio of 1.77, and 44% Mn recovery in the case of sample 1; whereas, a 33.75% Mn grade, with a Mn:Fe ratio of 1.66 at Mn recovery of 44% was reported for Sample 2. It was observed that both samples had a similar input chemistry (~28% Mn, ~1 Mn: Fe ratio) however, they had distinctive mineralogical assemblages. Furthermore, it was observed that the liberation of manganese mineral was in a course size range, i.e., 300 to 450 µm, while the association of iron and manganese bearing phases was lower in sample 1 when compared to sample 2.

Proposal for an Environmentally Sustainable Beneficiation Route for the Amphibolitic Itabirite from the Quadrilátero Ferrífero-Brazil

The high world demand for iron ores opposed to the rapid exhaustion of high-grade deposits from the main producing regions around the world has motivated the search and/or improvement of beneficiation routes, which enable the economic use of iron formations previously considered marginal ores, which have the potential to considerably increase mineable reserves due to their large volume. In this study, a sample of amphibolitic itabirite from the eastern region of the Quadrilátero Ferrífero, Minas Gerais, Brazil was characterized, aiming at its use in the industrial pelletizing circuit. The main physical characteristics of this ore are moisture = 10% and specific weight = 3710 kg/m3. The ore has a high grade of loss on ignition—LOI (6.7%) and P (0.14%). Through X-ray diffractometry (XRD), optical microscopy and scanning electron microscope—SEM, the ore was found to consist of 64.5% goethite (amphibolitic, alveolar, massive and earthy); 6.8% hematite (martitic, granular and lamellar) and 0.9% magnetite. The main gangue mineral is quartz (25.5%). Based on the results of concentration tests (magnetic and flotation) performed with the studied sample, the magnetic concentration route of deslimed sample followed by the addition of slimes in magnetic concentrate can be incorporated into the pelletizing process.

Tourmaline as a Recorder of Ore-Forming Processes in the Xuebaoding W-Sn-Be Deposit, Sichuan Province, China: Evidence from the Chemical Composition of Tourmaline

The Xuebaoding W-Sn-Be deposit located in the Songpan-Ganze Orogenic Belt (Sichuan Province, China) is a hydrothermal deposit with less developed pegmatite stage. The deposit is famous for the coarse-grained crystals of beryl, scheelite, cassiterite, apatite, fluorite, muscovite, and others. The orebody is spatially associated with the Pankou and Pukouling granites hosted in Triassic marbles and schists. The highly fractionated granites are peraluminous, Li-Rb-Cs-rich, and related to W-Sn-Be mineralization. The mineralization can chiefly be classified based on the wallrock and mineral assemblages as muscovite and beryl in granite (Zone I), then beryl, cassiterite and muscovite at the transition from granite to triassic strata (Zone II), and the main mineralized veins composed of an assemblage of beryl, cassiterite, scheelite, fluorite, and apatite hosted in metasedimentary rock units of marble and schist (Zone III). Due to the stability of tourmaline over a wide range of temperature and pressure conditions, its compositional variability can reflect the evolution of the ore-forming fluids. Tourmaline is an important gangue mineral in the Xuebaoding deposit and occurs in the late-magmatic to early-hydrothermal stage, and can thus be used as a proxy for the fluid evolution. Three types of tourmalines can be distinguished: tourmaline disseminations within the granite (type I), tourmaline clusters at the margin of the granite (type II), and tourmalines occurring in the mineralized veins (type III). Based on their chemical composition, both type I and II tourmalines belong to the alkali group and to the dravite-schorl solid solution. Type III tourmaline which is higher in X-site vacancy corresponds to foitite and schorl. It is proposed that the weakly zoned type I tourmalines result from an immiscible boron-rich aqueous fluid in the latest stage of granite crystallization, that the type II tourmalines showing skeletal texture directly formed from the undercooled melts, and that type III tourmalines occurring in the mineralized veins formed directly from the magmatic hydrothermal fluids. Both type I and type II tourmalines show similar compositional variations reflecting the highly fractionated Pankou and Pukouling granites. The higher Ca, Mg, and Fe contents of type III tourmaline are buffered by the composition of the metasedimentary host rocks. The decreasing Na content (<0.8 atoms per formula unit (apfu)) and increasing Fe3+/Fe2+ ratios of all tourmaline samples suggest that they precipitated from oxidized, low-salinity fluids. The decreasing trend of Al content from type I (5.60–6.36 apfu) and type II (6.01–6.43 apfu) to type III (5.58–5.87 apfu) tourmalines, and associated decrease in Na, may be caused by the crystallization of albite and muscovite. The combined petrographic, mineralogical, and chemical characteristics of the three types of tourmalines thus reflect the late-magmatic to early-hydrothermal evolution of the ore-forming fluids, and could be used as a geochemical fingerprint for prospecting W-Sn-Be mineralization in the Xuebaoding district.