Oxide Ore Research Articles

Prospects of Using Pseudobrookite as an Iron-Bearing Mineral for the Alkaline Electrolytic Production of Iron.

The alkaline electrolytic production of iron is gaining interest due to the absence of CO2 emissions and significantly lower electrical energy consumption when compared with traditional steelmaking. The possibility of using an iron-bearing pseudobrookite mineral, Fe2TiO5, is explored for the first time as an alternative feedstock for the electrochemical reduction process. To assess relevant impacts of the presence of titanium, similar electroreduction processes were also performed for Fe2TiO5·Fe2O3 and Fe2O3. The electroreduction was attempted using dense and porous ceramic cathodes. Potentiostatic studies at the cathodic potentials of −1.15–−1.30 V vs. an Hg|HgO|NaOH reference electrode and a galvanostatic approach at 1 A/cm2 were used together with electroreduction from ceramic suspensions, obtained by grinding the porous ceramics. The complete electroreduction to Fe0 was only possible at high cathodic polarizations (−1.30 V), compromising the current efficiencies of the electrochemical process due to the hydrogen evolution reaction impact. Microstructural evolution and phase composition studies are discussed, providing trends on the role of titanium and corresponding electrochemical mechanisms. Although the obtained results suggest that pseudobrookite is not a feasible material to be used alone as feedstock for the electrolytic iron production, it can be considered with other iron oxide materials and/or ores to promote electroreduction.

Genesis of magmatic ilmenite ores associated with the Mazua ultramafic intrusion, NE Mozambique

The Mazua ultramafic intrusion is among the most promising intrusions hosting Fe-Ti oxide ores in Mozambique. Fe-Ti oxide ores are mainly composed of ilmenite occurring as lenses, veins and layers, either massive or disseminated in hornblende pyroxenite. This study discusses the nature and origin of the intrusion and related ilmenite ore body on the basis of whole-rock and mineral chemistry. Textural and structural evidences support a cumulate origin for these rocks, including the occurrence of relict cumulate textures, layering of alternating oxides and silicate-rich rocks, and size-grading of silicate-rich layers. Primary magmatic features have, however, largely been overprinted by subsolidus processes. The occurrence of the cumulate assemblage (Fe-Ti oxides and clinopyroxene), without plagioclase and olivine, suggests that the magma underwent differentiation before its emplacement. The evolved magmatic nature of the intrusion is consistent with the calculated Mg-number of approximately 50 for the melt in equilibrium with clinopyroxene crystals. The high TiO2 concentrations (>4 wt%) of the evolved magma, by differentiation, are interpreted as the main factors controlling the crystallization of Fe-Ti oxides. We propose that the ores formed from crystallization and settling of Fe-Ti oxide minerals from an evolved basaltic magma. This model is consistent with (1) the occurrence of Fe-Ti oxides and clinopyroxene as cumulates in relation to the coexisting amphibole, (2) the layering structures of alternating oxides and silicate matrix, (3) the scarcity of apatite supported by the extremely low whole-rock P2O5 concentrations and (4) the restricted occurrence of ore veins, excluding the formation from immiscible oxide melts.

Enhanced microbial nitrate reduction using natural manganese oxide ore as an electron donor

Nitrate contamination of groundwater is a global problem. Enhanced biological nitrate reduction by liquid organics combined with low-cost natural materials (as electron donors) can cost-effectively remove nitrate from groundwater. Dissolved Mn(II) as an electron donor has been thoroughly investigated to support microbial nitrate reduction. However, most Mn in soil and sediments is in solid form, and the ability of solid-phase natural manganese oxide ore (NMO) as electron donor and for supporting microbial nitrate reduction is unknown. Therefore, a microcosm experiment was conducted to bridge this gap in knowledge. The results demonstrated that microbial nitrate reduction (mainly converted to nitrite) was enhanced by NMO (rich in cryptomelane). The electrochemical and X-ray photoelectron spectroscopy analyses suggested that NMO may be oxidized by microbial metabolism. Illumina Miseq sequencing results indicated that Acidovorax spp. played a crucial role in NMO-supported nitrate reduction. Further Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analyses indicated that bacterial extracellular electron transfer may be one of the mechanisms for the microbial NMO oxidation. The results of our study highlight the potential importance of NMO in nitrate reduction in the natural environment and may pave the way for NMO-assisted technology for nitrate removal from groundwater with less usage of organic electron donors.

Deposits of the Udokan-Chineysky ore-magmatic system of Eastern Siberia

The aggregate of ore deposits localized in the Udokan-Chineysky ore district is unique and is the result of multi–stage, polygenetic formation. The deposits of copper and other metals formed at various depths occur within a limited area. The oxide and sulfide ore are spatially associated in the sedimentary rocks pertaining to the Paleoproterozoic Udokan Supergroup and the intrusive mafic–ultramafic rocks of the Chineysky Complex. The granite rocks of the Kodar Complex and gabbro rocks of the Chineysky Complex also date back to Paleoproterozoic. The same age has been established for metasomatic Nb–Ta–Zr–REE–Y and U mineralization in the albitized terrigenous rocks of the Udokan Supergroup (Katugin deposit and Chitkanda prospect) and U–Pd prospects hosted in terrigenous rocks. The U–REE mineralization superposed on the titanomagnetite deposits in the Chineysky pluton has not analogues in the world’s practice. The occurrences of uranium mineralization have been noted in form of pitchblende and U–Th rims around chalcopyrite grains at the Unkur copper deposit hosted in sedimentary rocks. The enrichment in U and Pb has been documented in crosscutting quartz veinlets with bornite mineralization at the Udokan deposit.

Optimizing and Analyzing the Behavior of Impurities in the Leaching of a Low Carbonate Copper Oxide Ore

Optimizing and Analyzing the Behavior of Impurities in the Leaching of a Low Carbonate Copper Oxide Ore

Optimization of Flocculation and Sedimentation Parameters of Total Tailing Filling Material Based on Response Surface Method

Using sulfide ore and oxide ore tailings of a tin mine in Yunnan as raw materials, 17 groups of flocculation settling tests were designed by Box‐Behnken in Design‐Expert software, and the settling velocity and underflow concentration of mixed tailings with sulfur/oxygen ratio of 5 : 5 were studied. The effects of volume concentration, flocculant unit consumption, and flocculant concentration on settling velocity and underflow concentration were explored, and the optimal parameters of settling velocity and underflow concentration were obtained. Results. The best mixing parameters of mixed tailings are volume concentration of 17.66%, flocculant unit consumption of 39.589 g/t, and flocculant concentration of 0.195%. At this time, the settling speed is 2.231 mm/s and the underflow concentration is 65.289%. The flocculation settling velocity under this parameter condition was tested, and the experimental results were consistent with the predicted results of the model. This surface method can be used to design the flocculation and settlement test of mine tailings, which has certain guiding significance for the selection of parameters in actual production of mines.

Kinetic Study of the Acidic Leaching of a Domestic Copper Oxide Ore and Optimization of the Process Using Statistical Design of Experiments

Kinetic Study of the Acidic Leaching of a Domestic Copper Oxide Ore and Optimization of the Process Using Statistical Design of Experiments

Sulphuric Acid Bake-Leach Process for the Treatment of Mixed Copper-Cobalt Oxide Ores

A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-cobalt oxide ore was carried out by mixing the sample with sulphuric acid followed by baking of the mixture in a muffle furnace. Baking tests were conducted at different conditions such as temperature, time, and varying amounts of acid. The reacted samples were then subjected to water leaching at room temperature to determine the leachability of copper and cobalt from the baked material. The dissolutions of copper and cobalt were dependent on acid concentration with cobalt showing more sensitivity to the amount of acid. Both copper and cobalt were extracted from the baked material within short leaching times and without the addition of reducing agents. The outcome of this work has shown that the sulphuric acid bake-leach process is a possible alternative to the reductive leaching method for copper-cobalt oxide ores.

Enhanced performance and mechanisms of sulfamethoxazole removal in vertical subsurface flow constructed wetland by filling manganese ore as the substrate

Sulfamethoxazole (SMX), a typical sulfonamide antibiotic, is ubiquitous in secondary effluent and may pose undesirable effects on the aquatic ecosystem and human health. Constructed wetland (CW) is more and more applied in advanced sewage treatment, and the substrate plays an important role in removing pollutants. Manganese (Mn) ore has been widely concerned as a new type of substrate to remove pollutants in CW due to its high adsorption and redox properties. However, the removal mechanism of antibiotics by Mn ore CW is still unclear. In this study, Mn ore was selected as the substrate of a vertical flow constructed wetland (VFCW) while gravel substrate was selected as a control group, and the removal efficiencies of SMX in two VFCWs were investigated and compared. Experimental devices were layered as different regions, including anaerobic (0–32 cm), anoxic (32–64 cm) and aerobic (64–80 cm) zones, to examine the removal characteristics of SMX in different regions. And the removal mechanism of SMX was also explored by examining the adsorption and oxidation of Mn ore and the microbial degradation performance. The results showed that the final removal efficiency of SMX in CW filled with Mn ore substrate (M-CW) (48.4%) increased by 39.6%, compared with CW filled with gravel substrate (G-CW) (8.8%). According to the calculation of mass balance, the total loss of SMX caused by the oxidation of Mn ore and biodegradation accounted for 33.0% of the total SMX input in M-CW, the SMX loss caused by the biodegradation in G-CW accounted for 13.0%, and the substrate adsorption in M-CW and G-CW occupied 15.0% and 7.0% of the total SMX input, respectively. Mn(II) was formed during the oxidation of SMX by Mn(III, IV) and dissimilated Mn(III, IV) reduction by microorganisms in anaerobic environment (0–32 cm). Whereafter, the produced Mn(II) entered into the aerobic zone (64–80 cm) with the water flow and was re-oxidized into biogenic Mn oxides (BioMnOx) which had high adsorption and oxidation performance for SMX. Therefore, Mn ore could enhance SMX removal efficiency in anaerobic and aerobic zones by Mn redox process.

Geometallurgical Characterisation with Portable FTIR: Application to Sediment-Hosted Cu-Co Ores

Cobalt (Co) mine production primarily originates from the sediment-hosted copper (Cu) deposits of the Democratic Republic of Congo (DRC). These deposits usually consist of three ore zones with a supergene oxide ore blanket overlying a transition zone which grades into a sulphide zone at depth. Each of these zones display a mineral assemblage with varying gangue mineralogy and, most importantly, a distinct state of oxidation of the mineralisation. This has direct implications for Cu and Co extraction during mineral processing as it dictates which processing method is to be used (i.e., leaching vs. flotation) and affects the performance of these. To optimise resource efficiency, reduce technical risks and environmental impacts, comprehensive understanding of variation of ore mineralogy and texture in the deposit is essential. By defining geometallurgical ore types according to their inferred metallurgical behaviour, this information can serve to classify the resources and improve resource management. To obtain insight into the spatial distribution of mineral grades, it is necessary to develop techniques that have the potential to measure rapidly and, preferably, within the mine at relatively low-cost. In this study, the application of portable Fourier transformed infrared (FTIR) spectroscopy is investigated to measure the mineralogy of drill core samples. A set of samples from a sediment-hosted Cu-Co deposit in DRC was selected to test this approach. Results were validated using automated mineralogy (QEMSCAN). Prediction of gangue and target mineral grades from the FTIR spectra was achieved through partial least squares regression (PLS-R) combined with competitive adaptive reweighted sampling (CARS). It is shown that the modal mineralogy obtained from FTIR can be used to classify the ore according to type of mineralisation and gangue mineralogy into geometallurgical ore types. This classification supports selection of a suitable processing route and is likely to affect the overall process performance.

Influence of polysorbate 80 on flotation of zinc oxide ores with amine collector

Influence of polysorbate 80 on flotation of zinc oxide ores with amine collector

THE EFFECT OF PH VARIATIONS ON THE STRUCTURE OF THE MnFe2O4/PS NANOCOMPOSITE LAYER AS SELF CLEANING

Manganese is a metal element found in group VII, has an atomic weight of 54.93u, with a boiling point of 20320˚C, while the melting point is 12470˚C, and has a reddish-gray color. Iron (III) oxide (Fe2O3) or also known as hematite or maghemite iron ore, iron hematite (α – Fe2O3) is a simple oxide which has a hexagonal (rhombohedral) structure and has the R3c space group. Manganese was used as reinforcement in this research, while the matrix used was polystyrene. In this study, 5 variations of pH MnFe2O4/PS, namely 5,6,7,8 and 9 nanocomposites were synthesized using the spin coating method with manganese oxide (MnO2) and iron ore (Fe2O3) precursors. The composite gel is dropped on the glass substrate then the drying process is carried out in an oven. MnFe2O4/PS nanocomposites were characterized using X-Ray Diffraction (XRD). giving acid and alkaline solutions affects the size of the crystals, when adding a base (25% Na4OH) the crystal size becomes small while when the acid is added (100% CO3COOH) the crystal size is larger. : pH 8: pH 9 an increase in crystal size and grain size occurs.

Effect of ferric ion on cuprite surface properties and sulfidization flotation

The pulp from the sulfidization flotation of copper oxide ores contains several metal ions, among which ferric ion (Fe3+) depresses the flotation of copper oxide minerals. Thus, it is necessary to investigate the effect of Fe3+ on the sulfidization and xanthate adsorption of copper oxide minerals to provide theoretical support for mitigating the negative effects of Fe3+. In this work, the effect of Fe3+ on cuprite flotation was determined via micro-flotation tests. The mechanism of the depression of cuprite sulfidization by Fe3+ was revealed through zeta potential measurements, scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDS) analysis, and X-ray photoelectron spectroscopy analysis. The impact of Fe3+ on xanthate adsorption onto cuprite surfaces was investigated via surface-adsorption measurements and infrared spectroscopy. The micro-flotation test results indicated that the cuprite floatability was significantly weakened by Fe3+. The results of zeta potential, SEM-EDS, and X-ray photoelectron spectroscopy showed that Fe3+ could generate hydrophilic species and reduce the number of active sites on cuprite surfaces, thus hindering the formation of copper sulfide species on cuprite surfaces. The results of surface-adsorption measurements and infrared spectroscopy showed that xanthate hardly interacted with the Fe3+-treated cuprite surfaces. Given the above, Fe3+ could weaken the cuprite surface hydrophobicity by reducing the number of active sites on cuprite surfaces, thereby depressing the cuprite flotation.

Intensification of Nickel Bioleaching with Neutrophilic Bacteria Guyparkeria halophila as an Approach to Limitation of Sulfuric Acid Pollution.

Hydrometallurgical production of valuable and non-ferrous metals is traditionally accompanied with acid waste effluents/acid mine drainage leading to acidification of the mining areas. The traditional cause of this pollution is the well-known technology based on the recovery of metals with acid solutions and the application of strong acidophilic leaching bacteria for the oxidation of sulfide ores. In our experiments, we used neutrophilic autotrophic bacteria (NAB) stimulated with formic acid or coupled with acidophilic bacteria. The first approach was based on using formic acid as an energetic substrate by autotrophic bacteria. In the second case, the NAB provided initial biogenic acidification for the following growth of the inoculated acidophilic bacteria. Our experiments resulted in increased nickel recovery from the low-grade sulfide ores, which was provided by the NAB in a medium supplemented with formic acid. Bioleaching resulted in 1116 mg Ni/L (69.75%) in the medium with formate and only 35.4 mg Ni/L without formate in 43 days. As a whole, our bench scale experiments showed that the stimulated NAB can be effective at pH 7–5. Partially replacing sulfuric acid with formic acid could also give benefits via the following natural degradation of acid wastes. As a whole, this approach is more environmentally friendly than conventional bioleaching techniques.

Buried Fe-Mn nodules on the World ocean floor

Ocean floor Fe-Mn nodule sequence is a product of Mesozoic-Cenozoic global epoch of Fe-Mn oxide ore accumulation. Buried nodules formed in Late Paleocene-Eocene, Late Cretaceous, Cenomanian.

Innovative flotation for the utilisation of carbonate-bearing (siderite) iron ore using MS-2 as a dispersant

MS-2, a novel dispersant, was employed to improve the innovative dispersion flotation of carbonate-bearing refractory iron ore. High quality iron concentrates (TFe grade of 67.04% and recovery of 75.57%) were achieved by the locked-cycle flotation tests and analyzed by X-ray diffraction and scanning electron microscopy to investigate the surface morphology, which show the siderite slime coatings on hematite and quartz surfaces were effectively dispersed by MS-2. The dispersal mechanism was investigated via Zeta potential measurements and Fourier-transform infrared (FTIR) spectroscopy, which confirmed that MS-2 chemically adsorbed onto hematite surfaces, while physically adsorbed on quartz surfaces. Molecular dynamics simulations revealed the adsorption configurations of MS-2 onto both mineral surfaces, further confirming that the functional groups –COO‐ in MS-2 molecules interacted strongly with the Fe atoms on the hematite surface. Derjaguin-Landau-Verwey-Overbeek (DLVO) theory calculations indicated that the repulsive force between siderite and quartz or hematite became stronger after MS-2 was added, which weakened the siderite slime coatings on quartz and hematite. Therefore, MS-2 effectively dispersed the siderite or carbonate slime coatings from hematite and quartz surfaces and then restored the regular reverse anionic flotation for carbonate-bearing refractory iron oxide ores.

Separation of ferromanganese ore components by non-contact and contact carbothermic reduction

The possibility of joint selective solid-phase reduction of iron and phosphorus in ferromanganese ore has been experimentally confirmed. The experiments were carried out in a Tamman laboratory furnace at a temperature of 1000 °C and holding for two and five hours. The article presents results of the study of phase composition and phases' quantitative ratio of the reduction products, as well as chemical composition of the phases. It was established that reduction roasting in CO atmosphere provides a transition from oxide phase to metal phase only of iron and phosphorus. At the same time, the concentration of manganese oxide MnO increases in the ore oxide phase. The use of solid carbon as a reducing agent under the same conditions leads to transition to the metallic phase together with iron and phosphorus of a part of manganese. Based on the obtained data, it is proposed to selectively reduce iron and phosphorus at a temperature of 1000 °C with a reducing gas. Gas reduction will make it possible to use existing gas furnaces, in particular, multi-pod furnaces, for metallization of iron and phosphorus in ferromanganese ore, and natural gas, including hydrogen -enriched gas, and even pure hydrogen, as a reducing agent and energy carrier. Due to this, at the stage of ore metallization in production of manganese alloys, greenhouse gas CO2 emissions can be reduced. The results of the work can be used in the development of theoretical and technological bases for processing ferromanganese ores with a high content of phosphorus, which are not processed by existing technologies.

Mineralogical Characterization of Manganese Oxide Minerals of the Devonian Xialei Manganese Deposit

The Guangxi Zhuang Autonomous Region is an important manganese ore district in Southwest China, with manganese ore resource reserves accounting for 23% of the total manganese ore resource reserves in China. The Xialei manganese deposit (Daxin County, Guangxi) is the first super-large manganese deposit discovered in China. The Mn oxide in the supergene oxidation zone of the Xialei deposit was characterized using scanning electron microscopy (SEM), energy spectrometer (EDS), transmission electron microscopy (TEM, HRTEM), and X-ray diffraction analysis (XRD). The Mn oxides have a gray-black/steel-gray color, a semi-metallic-earthy luster, and appear as oolitic, pisolitic, banded, massive, and cellular textures. Scanning electron microscopy images show that the manganese oxide minerals are present as fine-spherical particles with an earthy surface. TEM and HRTEM indicate the presence of oriented bundled and staggered nanorods, and nanopores between the crystals. The Mn oxide ore can be classified into two textural types: (1) oolitic and pisolitic (often with annuli) Mn oxide, and (2) massive Mn oxide. Pyrolusite, cryptomelane, and hollandite are the main Mn oxide minerals. The potassium contents of cryptomelane and pyrolusite are discussed. The unit cell parameters of pyrolusite are refined.

Characterisation of Parameters Influencing the Phase Separation in Copper Solvent Extraction Systems Using Oxime-Type Extractants for the Field Operation

Solvent extraction (SX) is one of the most widely applied hydrometallurgical processes in copper production from oxide ore. As the high-grade ore deposits have been developed and depleted, now only low-grade ore deposits are being developed and are therefore facing obstacles of extreme processing conditions. This results in leaching gangue minerals and requires a more complicated solvent extraction system. Recently, synergistic solvent extraction has been introduced to separate copper from the leached solution with high impurities. However, operational obstacles arise due to the complicated solvent extraction process, including multi-stages of extraction, and using more than one extractant in a single solvent extraction system. The phase separation in solvent extraction is one of the major issues in field operation. A poor phase separation could affect the entire process and eventually cause production loss. Therefore, in this study, the phase separation behaviours were studied in consideration of the field operation. Major parameters considered in the study were the type of diluent, temperature, mixing speed, solution pH and Oxidation Reduction Potential (ORP), and addition of impurities (flocculant and colloidal silica). The phase separation behaviours in the continuous counter-current SX system using a pilot-scale mixer-settler in the above conditions was investigated.

The extraction of tin (Sn) from primary tin ore deposits using wet chlorination

More than half of the world’s tin production is from secondary ore deposits. However, along with its depletion, PT Timah Tbk has explored and mined the primary deposits in Belitung, one that is expected to become tin’s new source. Tin was found liberated as cassiterite in the secondary deposits, while in the primary, it was associated with other minerals requiring more complex processing. Therefore, a suitable technology is needed to extract the tin from the primary ore deposits. This research aims to observe the extraction of tin from primary deposits (oxide and skarn ores) using HCl wet chlorination, observed at different temperature (60 – 90°C), HCl concentrations (10 – 50 % excess of stoichiometric amount), leaching time (60 – 300 minutes), and with or without the addition of oxidant (hydrogen peroxide, H2O2). The research found that the highest percentage of tin extraction from oxide and skarn ores was 92.32% and 97.28%, respectively. Both results were achieved at the same optimum condition: temperature of 60°C, 50% excess of HCl, 240 minutes of leaching time, and at two-fold excess of the stoichiometric amount of H2O2. It was concluded that oxidative wet chlorination could be used to recover tin from its primary ore deposits.