Search Results (44)

The co-occurring relationships between ilmenite and gangue minerals in ilmenite deposits, as well as fine mineral embedding particle sizes, are complex. During the beneficiation process, grinding ilmenite finely is necessary to achieve sufficient individual mineral dissociation and the efficient recovery of ilmenite. During this process, a large number of fine-grained minerals can easily be generated, which adversely affects flotation separation. Micro–nanobubbles have been proven to effectively enhance the flotation separation efficiency of fine-grained minerals, as their cavitation characteristics are closely related to the flotation performance of the minerals. In order to fully understand the cavitation characteristics of micro–nanobubbles and their impact on the flotation recovery of fine-grained ilmenite, a series of experiments were conducted using methods such as the bubble cavitation property test, micro-flotation experiments, zeta potential analysis, the contact angle test, adsorption capacity detection, and PBM monitoring. The results indicate that during the process of slurry cavitation, appropriate concentrations of 2-octanol, cycle treatment times, and external inflation volume are conducive to the formation of micro–nanobubbles. Compared with deionized water without cavitation, cavitated micro–nanobubble water is more beneficial for the flotation separation of fine particulate ilmenite, titanaugite, and olivine. The presence of micro–nanobubbles can effectively promote the adsorption of combined collectors on mineral surfaces, significantly enhancing the hydrophobicity of the minerals, with an even stronger promoting effect observed under the treatment of 2-octanol. Micro–nanobubbles can adsorb a portion of the collectors originally attached to the mineral surfaces, thereby decreasing the absolute value of the surface potential of the minerals, which is beneficial for mineral aggregation. The introduction of micro–nanobubbles promotes the aggregation of fine ilmenite iron ore particles into flocculent bodies. 2-Octanol can reduce the size of the micro–nanobubbles generated during the cavitation process of the mineral slurry and, to a certain extent, weaken the phenomenon of bubble coalescence, so they demonstrate a greater advantage in facilitating the aggregation phenomenon. Full article

Combining carbon materials with oxides in a hybrid electrode is an effective way to control supercapacitor performance in terms of balancing energy and power density with cycling stability. However, it is still unclear how the mixing method of each component affects the supercapacitor performance. In this study, the influence of mixing reduced graphene oxide (rGO) with ilmenite-type nickel-manganese oxide (NiMnO₃) on the capacitive behaviour of the resulting composites is investigated. Two preparation methods are compared: mechanical mixing and ultrasonication. The capacitive characteristics were evaluated in hybrid supercapacitors using 6M KOH electrolyte. The bulk, surface, and morphological changes of the composites after long-term cycling were probed by EIS and ex situ XRD, XPS, and SEM analyses. It is established that the composites obtained by mechanical mixing exhibit better performance due to the stable contact between rGO and NiMnO₃ particles, favourable surface reactions with KOH and preserved morphology of rGO. These findings indicate that efficient hybrid electrodes can be achieved without relying on costly synthesis techniques such as hydrothermal or ultrasonic treatments. Full article

Ilmenite, the most widely distributed titanium ore resource globally, often coexists with titanaugite, one of its primary gangue minerals, which shares similar surface properties. This similarity significantly hampers the selective flotation separation efficiency of ilmenite. This study investigated the influence of grinding media shape—specifically steel balls, steel rods, and steel cylpebs—on the grinding characteristics of ilmenite and titanaugite through single-mineral micro-flotation experiments and related characterizations, and explored the potential of media shape to enhance the selective flotation separation of ilmenite. Experimental results demonstrate that in a weakly alkaline sodium oleate (NaOL) system at pH ≈ 8, the floatability of ilmenite milled with cylpebs is approximately 1.7% higher than that with balls and slightly lower than that with rods. In contrast, the floatability of titanaugite milled with cylpebs is similar to that with balls but almost 4% lower than that with rods. Compared to balls and rods, the difference in floatability between ilmenite and titanaugite increases from 29.96% and 29.04% to 32.71% with cylpeb milling. The primary reason is that cylpebs increase the exposure of the (104) face of ilmenite by approximately 2%, enhancing its interaction with NaOL, while minimizing the (−221) faces in titanaugite, thereby reducing its adverse impact on ilmenite flotation. Therefore, the use of cylpebs may facilitate the selective flotation separation of ilmenite. Full article

Ilmenite concentrate has emerged as the key titanium raw material for exploitation and utilization, playing a crucial role in the preparation of metallic titanium and titanium dioxide. However, the presence of impurities such as Fe, Ca, and Mg in ilmenite concentrate severely restricts its economic utilization and environmentally friendly applications. In our previous research, a novel process was proposed to prepare TiCl₄ from high-Ca- and Mg-containing ilmenite through carbothermal reduction and boiling chlorination. Nevertheless, the employment of graphite as a reducing agent and hydrochloric acid for metallic iron separation led to elevated production costs. The aim of this study was to explore an alternative and more cost-effective method. Petroleum-derived coke was used as the reducing agent to investigate the feasibility of producing titanium oxycarbide from ilmenite concentrate via carbothermal reduction and magnetic separation. The results showed that petroleum-derived coke is capable of reducing ilmenite concentrate to coral-shaped TiC_xO_y under high-temperature conditions. However, an approximate 100 °C increment in temperature is required to reach an equivalent reduction efficiency compared with graphite. The X-ray diffraction (XRD) analysis results of the reduced products reveal that complete reduction of ilmenite concentrate by petroleum-derived coke can only be achieved when the reduction process is conducted at 1600 °C for 3 h or at 1500 °C for 5 h. The reduced product obtained at 1600 °C, characterized by a substantial presence of dense Ti₂O₃, exhibits a significantly coarser particle size after 30 minutes of ball milling in contrast to the reduced product obtained at 1200 °C, which is rich in M₃O₅ anosovite. Magnetic separation results showed that the reduction product at 1200 °C could not have metallic iron removed by magnetic separation at 1.2 T, while the reduction product at 1600 °C could yield a non-magnetic charge rich in Ti₂O₃ and TiC_xO_y with an iron content as low as 2 ± 0.03 wt.%, which fully meets the requirements for producing TiCl₄ by boiling chlorination. Overall, these research results offer a new approach for the low-cost production of TiCl₄ from ilmenite concentrate with high levels of Ca and Mg impurities through boiling chlorination. Full article

Transverse-field high-gradient magnetic separators (HGMSs) are an important complement to longitudinal-field HGMSs in mineral processing due to their several advantages. However, the processing capacity of the transverse-field HGMS is smaller than that of the longitudinal-field HGMS. Consequently, research on the optimization of the matrix box for improving the processing capacity is essential. This work investigates the optimization of the matrix box for the SSS^® HGMS to enhance the ilmenite separation efficiency and processing capacity. The results show that the matrix’s influence on separation performance is primarily influenced by the diameter of the rod matrix, the filling ratio, the depth of the matrix in the direction of slurry flow, and the ore unloading efficiency. Ilmenite pre-concentration tests are carried out using a test sample ore from Panzhihua, China. Pilot-scale validation research is carried out. The test results indicate that the depth of the matrix box should not be considerably thick, as an excessive number of layers increases the capture zone, but simultaneously reduces the unloading efficiency. The depth of the matrix box should neither be considerably thick nor particularly thin, as this would result in low processing capacity. Meanwhile, the segmented multi-layer matrix box should be used to balance the capturing and unloading performance. Finally, an optimal double-layer matrix ring is applied to the industrial transverse-field HGMS, and its inner and outer rings are equipped with matrix boxes with ϕ3 mm and ϕ2 mm rods, respectively, which improves its pre-concentrate efficiency and processing capacity. The concentrate indexes of the transverse-field HGMS is achieved with a TiO₂ grade of 18.01% and a recovery of 87.28%, which is better than the separation indexes of the longitudinal-field HGMS. Full article

With the development of mineral resources, minerals are becoming increasingly difficult to process. In order to utilize these resources more effectively, in-depth research into process mineralogy has become increasingly important in the field of mineralogy, and particle size measurement under the microscope is one of the critical aspects of process mineralogy. At present, the use of scanning electron microscopes and other equipment for measurement is very expensive, and manual measurement has problems such as poor accuracy and low efficiency. In addition, there is a lack of reference materials for the segmentation algorithm of mineral light images. This article proposes a Gaussian pyramid based on bilateral filtering combined with directional maximum intercept to measure mineral particle size under the microscope. In the experiments, different segmentation algorithms were studied, including Gaussian pyramid segmentation based on bilateral filtering, segmentation based on Fuzzy C-Means, and the rapidly developing deep learning segmentation algorithms in recent years. By comparing the segmentation effects of these three algorithms on various mineral thin-section images, the Gaussian pyramid segmentation algorithm based on bilateral filtering was selected as the optimal one. This was then combined with the directional maximum intercept method to measure the particle size of ilmenite and pyrite images. The experimental results show that the segmentation method based on the bilateral filtering Gaussian pyramid technique has higher segmentation accuracy than the other two algorithms, and can accurately measure the particle size of minerals under the microscope. Compared with manual measurement, this method can effectively and accurately measure the microscopic particle size of target minerals, greatly reducing the workload of measurement personnel and reducing the time spent on measurement. Full article

The article theoretically justified and experimentally confirmed the possibility of implementing the process of the electric melting of Satbayevskiy ilmenite concentrates with new fluxing additives based on oxides and nitrides of aluminium, calcium, and boron. They also include boron carbonitride CNV that will expand the raw material base of Kazakhstan titanium production by involving local substandard material in the process, as well as the technical and economic performance of electric melting. In order to conduct experiments in the area of extremum, the ilmenite concentrate from the Satbayev deposit was taken. Furthermore, the optimum conditions of the electric melting of Satbayevski ilmenite concentrates (such as the process temperature of 1550–1600 °C, the reducing agent consumption of 8–10% of the concentrate mass, and the duration of 90 min), using new fluxing additives, were selected. As a result of the experiment (performed at a temperature of 1600 °C), it has been found that the introduction of 3 to 6% of fluxes in the charge of electric melting promotes the reduction of iron oxides from 45 to 80% and achievement of the extraction of titanium oxide in slag of up to 83.5–90.1%. The addition of 6% boron oxide and carbonitride in the charge of electric melting reduces the melting temperature of the charge to ~1400–1450 °C and the melting time to 90 min. It also creates conditions for a quieter electric melting mode. Full article

This work presents the results of thermodynamic and technological studies of the reducing electric smelting of low-quality and difficult-to-recover Satpaevsk ilmenite concentrates in the presence of sodium carbonate (Na₂CO₃) as a flux. In the course of thermodynamic studies, according to literature data and using the HSC Chemistry 8 program, the state diagrams of the FeO-TiO₂, FeO-Fe₂O₃-TiO₂, Na₂O-TiO₂, Na₂O-SiO₂, Ti-C-O and Fe-C-O systems and the possibility of reactions in the temperature range of 500–1600 °C (without smelting of titanium, 1678 °C), taking into account phase transitions, were studied. The article also presents the results of technological studies of the above process. In general, the research results showed the possibility of using sodium carbonate (Na₂CO₃) as a flux in the charge of the electric smelting of low-quality Satpaevsk ilmenite concentrates. It has been established that the addition of 4.5–5% of Na₂CO₃ allows for reducing the temperature and the duration of electric smelting, the viscosity of the melt, and the complete separation of the smelting products (cast iron from slag). Full article

In addition to bubble–particle interaction, particle–particle interaction also has a significant influence on mineral flotation. Fine particles that coat the mineral surface prevent direct contact with collectors and/or air bubbles, thereby lowering flotation recovery. Calculating the particle interaction energy can help in evaluating the interaction behavior of particles. In this study, the floatability of coarse ilmenite (−151 + 74 μm) and different particle sizes (−45 + 25, −25 + 19, −19 μm) of forsterite with NaOL as a collector was investigated. The results showed that forsterite sizes of −45 + 25 and −25 + 19 μm had no effect on the ilmenite floatability, whereas −19 μm forsterite significantly reduced ilmenite floatability. A particle size analysis of artificially mixed minerals and a scanning electron microscopy (SEM) analysis of the flotation products showed that heterogeneous aggregation occurred between ilmenite and −19 μm forsterite particles. The extended DLVO (Derjaguin–Landau–Verwey–Overbeek) theory was applied to calculate the interaction energy between mineral particles using data from zeta potential and contact angle measurements. The results showed that the interaction barriers between ilmenite (−151 + 74 μm) and forsterite (−45 + 25, −25 + 19, and −19 μm) were 11.94 × 10³ kT, 8.23 × 10³ kT and 4.09 × 10³ kT, respectively. Additionally, the interaction barrier between forsterite particles smaller than 19 μm was 0.51 × 10³ kT. The strength of the barrier decreased as the size of the forsterite decreased. Therefore, fine forsterite particles and aggregated forsterite can easily overcome the energy barrier, coating the ilmenite particle surface. This explains the effect of different forsterite sizes on the floatability of ilmenite and the underlying mechanism of particle interaction. Full article

Weighting materials such as barite and ilmenite are crucial for controlling fluid density during deep or ultra-deep drilling operations. However, sagging poses significant challenges, especially in highly deviated high-pressure and high-temperature (HP/HT) wells. This leads to inadequate well control, wellbore instability, and variations in hydrostatic pressure in extended-reach wells. Given the challenges of experimental research, reliable prediction models are imperative for evaluating the interaction between the ratio of anti-sagging additives, temperature, and wellbore inclination on sag factor (SF). This research presents statistical-based empirical models for predicting the SF at various wellbore inclinations (0°, 30°, 45°, 60°, 70°, 80°, and 90°) and assessing the influence of fly ash on the SF. The regression equations, developed using the Response Surface Methodology in Minitab 18 software, show high reliability, with R² values approaching unity. Contour and surface response plots provide a clear understanding of the variable interactions. The analysis reveals that sagging is most severe at 60° to 65° inclination. At 400 °F and 60° inclination, adding 4 lb/bbl of fly ash reduces sagging in barite and ilmenite-densified fluid by 63.9% and 63.1%, respectively. Model validation shows high accuracy, with percentage errors below 3%. This study offers valuable insights for optimizing drilling fluid formulations in HP/HT well environments. Full article

Global population growth requires the use of various natural resources to satisfy the basic needs of humanity. Fossil fuels are mainly used to produce electricity, transportation and the artificial air conditioning of habitats. Nevertheless, countries around the world are looking for alternative energy sources due to the decrease in the availability of these fuels and their high environmental impact. The mixture of hydrogen and carbon monoxide (H₂ + CO), commonly called syngas, is a high-value feedstock for various industrial applications. By varying the composition of syngas, especially the H₂/CO molar ratio, it can be used to produce methanol, fuels or synthetic natural gas. However, when this ratio is very low, the separation of this gas usually represents a great problem when making the energy balance, which is why it is proposed to adapt a combustion process in chemical cycles, taking advantage of the energy of this gas, reducing the energy impact of the process. During the present project, mass and energy balances were developed for combustion in chemical cycles, using ilmenite as a carrier, integrating heat exchangers to take advantage of the residual energy at the output of the process, to preheat the inlet current in the regenerator. Here, a comparative was made at different temperatures of the air stream and evaluating the mechanism of the ilmenite when a syngas stream is used as fuel. Full article

Plasma technology has emerged as a very helpful tool in a variety of sectors, notably metallurgy. Innovators and scientists are focused on the problem of finding a more ecologically friendly way of extracting titanium and iron metal from natural ilmenite concentrate for industrial applications. A direct current (DC) plasma torch operating at atmospheric pressure is used in this study to describe a decarbonization process for reducing an ilmenite concentrate. The plasma gases employed in this torch are CO₂ and CH₄. The molar ratio of the gases may be crucial for achieving a satisfactory reduction of the ilmenite concentrate. As a result, two molar ratios for CO₂/CH₄ have been chosen: 1:1 and 2:1. During torch operation, a thin layer of graphite is formed on the cathode to establish a protective barrier, prolonging the cathode’s life. The material was analyzed using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The output gases were analyzed using mass spectrometry (MS). In addition, a thermodynamic analysis was performed to predict the development of thermodynamically stable phases. An economic assessment (including capital expenditures (CAPEX) and operating expenditures (OPEX)) and a carbon balance were developed with the feasibility of the piloting in mind. Full article

The Xiangzhong district is the largest low-temperature W-Au-Sb metallogenic area in the world. The Darongxi skarn W deposit in the north of the Xiangzhong district is closely related to biotite monzonite granite, muscovite monzonite granite, and felsophyre, but the nature of granitic magma and its relationship with mineralization is relatively weak. In this paper, U-Pb dating, Lu-Hf isotope, the in situ composition of zircon, and the apatite of biotite monzonite granite, muscovite monzonite granite, and felsophyre in the Darongxi mining area are systematically studied, and the formation age, magma property and source, and their relationship with mineralization are discussed. The values of zircon U-Pb age and the ε_Hf(t) of biotite monzonite granite are 222.2 ± 0.54 Ma and −2.9~−6.4, respectively. The values of zircon U-Pb age and the ε_Hf(t) of muscovite monzonite granite are 220.8 ± 0.58 Ma and −2.7 to −8.1, respectively. The values of zircon U-Pb age and the ε_Hf(t) of felsophyre are 222.3 ± 2.20 Ma and −2.2~−5.4, respectively. Magmatic apatite grains from biotite monzonite granite and muscovite monzonite granite show distinctive core–rim and oscillatory zoning textures in CL images, and demonstrate a bright yellow in colorful CL images. The magmatic apatite has a total rare earth concentration (3766~4627 ppm), exhibiting right-inclined nomorlized rare earth element patterns and obvious negative Eu anomalies. The geochemical data of magmatic zircon and apatite indicate that magma sources are responsible for these intrusions in the Darongxi mining area, mainly derived from the partial melting of the Mesoproterozoic crust, which is rich in W; the magma is rich in F and poor in Cl (F = 2.4~3.3 wt%, Cl = 0.0024~0.0502 wt%). The oxygen fugacity of magmatic zircon (ΔFMQ_AVG = −4.02~−0.26), the high negative Eu anomaly (δEu = 0.06~0.12) and the low positive Ce anomaly (δCe = 1.09~1.13) of magmatic apatite, and the occurrence of ilmenite all indicate that the redox condition of magma from the Darongxi mining area is reduced. The reduced F-rich crust-source granitic rock and W-rich source provide favorable conditions for the mineralization of the Darongxi reduced skarn W deposit. Full article

TiO₂ production is a key part of Ti metallurgy and Ti recycling, and the process itself has turned out to be energy-consuming and material-consuming. New technologies are needed to utilize complex Ti ores, such as ilmenite, and reduce the carbon footprint of TiO₂ extraction. Ammonium sulfate roasting has been revealed as an efficient way to carry out phase transformations of complex minerals. A low-temperature sulfation roasting approach was studied to chemically breaking down the crystal structure of ilmenite and generate metal soluble sulfates simultaneously. These roasted products were introduced to water leaching, then the residue of the water leaching was leached by diluted HCl acid, and the TiO₂ product was enriched in the leaching residue. The effects of roasting temperature, roasting time, ilmenite-to-ammonium sulfate mass ratio, ilmenite particle size, and second-stage roasting on iron removal and titanium loss leaching efficiency were systematically studied. The results show that the optimum roasting conditions were a roasting temperature of 500 °C, a roasting time of 210 min, an ilmenite-to-(NH₄)₂SO₄ mass ratio of 1:7, and an ilmenite particle size of below 43 µm. Under optimized conditions, the TiO₂ grade in the obtained synthetic rutile reached 75.83 wt.%. Furthermore, the phase transformation and reaction mechanism during roasting are discussed and interpreted. Full article

Fabrication of chitosan and ilmenite sand-based novel photocatalysts through the catalytic graphitization of chitosan is reported. Nanocomposites consisted of TiO₂, Fe₂O₃ and Fe nanoparticles dispersed on a nitrogen-doped graphitic carbon framework. The surface area, pore volume and macropore structure of the carbon matrix is disturbed by the heterogeneously distributed nanoparticles. The extent of graphitization expanded with increasing metal loading as indicated by variation in the I_D/I_G ratio. The nanomaterial’s surface consists of Fe³⁺ and Ti⁴⁺, and graphitic, pyridinic and pyrrolic nitrogen were found in the carbon matrix. The band gap values of the composites varied in the 2.06–2.26 eV range. The photocatalytic activity of the synthesized nanomaterials was determined, and the highest rate constant for the photodegradation of methylene blue under sunlight was 4.4 × 10⁻³ min⁻¹, which resulted with 10 mg/L MB and 25 mg of the best-performing catalyst. The rate constant rose with increasing concentrations of persulfate added to the medium. The rate constant greatly diminished with the addition of isopropyl alcohol as it scavenged hydroxyl radicals. The presence of co-pollutants including Pb²⁺, rhodamine B, PO₄³⁻ and Cl⁻ curtailed the rate of reaction. The activity reduced with an increasing number of uses of the catalyst. Full article