Ore Processing Research Articles

Evolution law and transformation mechanism of force chains in the flow of photoelastic particles under a flexible barrier

The essence of large deformation flow in loose geological bodies lies in the breaking and rebuilding of force chains at the microscopic scale. Therefore, it is crucial to investigate force chains during particle flow processes. This study focuses on particle flow during the ore drawing process, develops a photoelastic experiment model, investigates the evolution law of force chains, reveals the transformation mechanism of strong and weak force chains, and provides insights for removing particle blockage in mining engineering. The results show that strong force chains are primarily located on both sides of the model, with fewer numbers, and extend toward the side boundaries in a direction close to 70°. Weak force chains are predominantly distributed in the middle section of the model, with numerous and uniformly developed directions. In addition, under the effects of self-organization and hetero-organization, the particles' sliding and rolling cause the buckling of force chains and the rearrangement of particles, resulting in the transformation between strong and weak force chains and accelerating the particles' flow. The research results deepen the understanding of the granular material large deformation flow-slip problem and provide a reference for similar engineering analyses.

Gamma Spectrometry Analysis of Natural and Man-Made Radioactivity and Assessment of Radiological Risk in Soils Around Steel Industry

"In this paper low background high-resolution gamma spectrometry was used for the determination of the activity concentrations of the natural and man-made radionuclides in topsoil samples collected in the vicinity of a large steel plant in Galati, Romania. Their values (mean ± standard deviation) for 238U, 226Ra, 232Th, 235U, 210Pb, 40K and 137Cs were: 38.1 ± 6.2; 35.9 ± 5.4; 35.5 ± 3.0; 1.8 ± 0.4; 47.3 ± 8.6; 504.5 ± 38.9 and 7.2 ± 4.7 Bq·kg–1, respectively. 60Co and 241Am had activities below the detection limit: 0.6–1.3 and 2.2–4.7 Bq·kg–1, respectively. The results indicate inputs of natural radionuclides in the sites close to the slag dump, raw materials transportation facility, ore and coal processing factories, blast furnaces, and iron scrap deposit. The evaluation of the associated radiological impact was performed based on selected hazard parameters: absorbed gamma dose rate, total external gamma dose rate, radium equivalent activity index, external hazard index, representative level index, annual effective dose, excess lifetime cancer risk, and annual gonadal dose."

Textural mapping and building a paragenetic interpretation of hydrothermal veins

Abstract Paragenetic interpretation, defined as the process of constraining the order in which the phases (minerals) comprising a rock formed, are fundamental in all disciplines requiring a detailed mapping of the genetic relationships between the investigated crystal(s) and their surrounding phases. Ore geology, geochronology, petrological and fluid inclusion studies are underpinned by a robust interpretation of the paragenesis. Without this understanding, the interpretation of the analytical data will be greatly restricted and potentially wrong. Textural mapping is particularly useful for studying phases precipitated into hydrothermal veins because the host many metallic ore deposits. Understanding the paragenesis and the association of ore minerals feeds directly into the approach taken towards exploration, mining operation and ore processing. Apart from ore deposits, precipitation of hydrothermal phases occurs in any setting where hot fluids interact with rock or sediment (e.g. CCS storage; geothermal facilities). This paper summarizes the principles for developing a robust paragenetic interpretation, including demonstrating the practical workflow via a case study from a sulfide-bearing vein near Loch Tay, Scotland. The principles and the workflow outlined in this paper are applicable to any discipline and route of investigation that necessitates a robust understanding of the relationships of the phases in a rock.

Phase transformation of Cr(VI) host-mineral driven by citric acid-aided mechanochemical approach for advanced remediation of chromium ore processing residue-contaminated soil

The slow release of Cr(VI) from chromium ore processing residue-contaminated soil (COPR-soil) poses a significant environmental and health risk, yet advanced remediation techniques are still insufficient. Here, the slow-release behavior of Cr(VI) in COPR-soil is observed and attributed to the embedded Cr(VI) in the lattice of vaterite due to the isomeric substitution of CrO42- for CO32-. A citric acid-aided mechanochemical approach with FeS2/ZVI as reductive material was developed and found to be highly effective in remediating COPR-soil. Almost all Cr(VI) in COPR-soil, including Cr(VI) embedded in the minerals, are reduced with a reduction efficiency of 99.94%. Cr(VI) reduction kinetics indicate that the Cr(VI) reduction rate constant in the presence of citric acid was 4.8 times higher compared to its absence. According to the Raman spectroscopy, X-ray diffraction (XRD), and Electron Probe X-ray Micro-Analyzer (EPMA) analysis, the reduction of Cr(VI) embedded in vaterite was mainly attributed to the citric acid-induced protonation effect. That is, under the protonation effect, the embedded Cr(VI) could be released from vaterite through its phase transformation to calcite, whose affinity to Cr(VI) is low. While the reduction of released Cr(VI) could be promoted due to the complexation of citric acid with disulfide groups on FeS2/ZVI. The results of long-term stability tests demonstrated that the remediated COPR-soil exhibited excellent long-term stability, which may also be associated with improved utilization of available carbon and electron donors by the Cr(VI) reducing bacteria (Proteobacteria)-dominated microbial community in the presence of citric acid, thereby promoting to establish a stable reducing microenvironment. Collectively, these findings will further our understanding of the reduction remediation of COPR-soil, especially in the case of Cr(VI) embedded in minerals.

Heat Transfer Conditions in Hydrogen-Fired Rotary Kilns for Iron Ore Processing

Heat Transfer Conditions in Hydrogen-Fired Rotary Kilns for Iron Ore Processing

Investigation of the beneficiation of refractory ferromanganese ores “Zhomart” deposits

In order to provide ferroalloy production with high-quality raw materials, the need to develop technologies for processing of low-grade manganese and ferromanganese ores is becoming increasingly important. In view of the change in the quality characteristics of ores, the decrease in manganese content and the ability to beneficiation by traditional methods, it is necessary to consider new approaches and technological solutions. The article presents data from a study on the beneficiation of refractory iron-manganese ore from the Zhomart deposit. The mineralogy, physical and mechanical properties, and granulometric composition of the ore were determined. The results of a study on gravitational beneficiation using a laboratory pulsator with a pneumatic drive and a laboratory 2-chamber diaphragm jigging machine and magnetic beneficiation of ore with a high-intensity magnetic field are presented. Iron-containing concentrate (Fe-45% and Mn-6.5% is mainly represented by hematite mixed with non-metallic minerals quartz and calcite) and iron-manganese concentrate (Mn-21.7% and Fe-21.1% in the form of hematite, Brownite and pyrolusite, also mixed with quartz and calcite). The concentrates are not suitable for smelting manganese-containing ferroalloys but can be used in the process of electrothermal beneficiation with selective carbothermal reduction of iron in an ore-thermal furnace. The smelting products can be manganese cast iron and iron-free, low-phosphorus limiting manganese slag with a high ratio of manganese to iron.

RELATIONSHIP «RARE-EARTH METALS – ENERGY TRANSITION IN THE CONTEXT OF FULL CYCLE PROJECTS

The article examines the development of the rare earth industry in Russia. Russia has a significant resource base of this type of mineral raw materials, but it does not fully use the existing potential. Russia exports semi-products of low processing, and imports goods containing rare earth elements with high added value. The key problem of the industry is the insignificant domestic demand for rare earth metals. The growing interest in the world in renewable energy sources makes new opportunities for the development of the Russian rare earth industry and gives a chance for the transition of the Russian economy to a new technological order. At the heart of the policy to create demand for rare earth products within the country, the authors propose to use a theoretic approach based on the consideration of full-cycle projects. Three main features characterize this approach. Firstly, our approach is an extension of the traditional project approach and takes into account not so much the local aspects of a separate project for the extraction and processing of ore, but its integration into the country's economy through a system of intersectoral interactions (multiplicative effects). Secondly, as the demand for products within the country grows and the scale of the use of products based on rare earth metals expands, the process of “learning” is launched - the costs of mining, processing and production of final products are reduced. Thirdly, the approach proposes to consider rare earth ores in dumps as pseudo-financial assets with the ability to manage them as traditional economic asset

Extraction of various valuable elements from oceanic manganese nodules using coal gasification slag via reduction roasting-acid leaching process

In line with the concept of coal gasification slag treatment and marine mineral exploitation, this research proposed a residual carbon roasting-acid leaching process to extract various valuable metals from oceanic manganese nodules. The residual carbon obtained from coal gasification coarse slag was enriched via gravity separation without chemical treatment, and this carbon-high product served as an inexpensive reducing agent. The feasibility of carbon-high reduction of oceanic manganese nodules was explored using a thermogravimetric-mass spectrometric coupling system and thermodynamic analysis. The influence of mass ratio, roasting time, and roasting temperature on the reduction effect of oceanic manganese nodules was examined, and optimal conditions were determined through orthogonal tests. The results demonstrated that under the optimized conditions, the leaching rate of Mn exceeded 98%, and that of Cu, Co, and Ni exceeded 96%. The reduction and leaching processes were elucidated at the crystal scale through various ways. Finally, a comprehensive process flow diagram was summarized for the extraction of various valuable metals from oceanic manganese nodules using the residual carbon roasting-acid leaching process. This research will pave the way for the design of cost-effective and sustainable roasting reductants and reduction roasting processes for manganese oxide ores, contributing to economic and environmental benefits.

Raising of Embankment of an Ore Tailings Pond and an Analysis of its Stability

Abstract The article presents a method for the intensification of a tailings pond. A tailings pond serves for the hydraulic storage of silt-sand waste arising during a flotation treatment and the processing of polymetallic ores. The intensification of the tailings pond consisted of raising its dam system to increase its accumulation space. The total proposed height of the tailings pond dam system after its elevation will be 60 m. The structural and shape arrangement of the dam in the dam system of the tailings pond was the result of a stability analysis of the state of the tailings pond before and after the dam system was raised. The article presents the results of experimental verifications of the geomaterial properties that form quasi-homogeneous units of the tailings pond (subsoil, dam system, and sediment) that serve as the inputs for stability analyses. New limiting and critical water levels are modelled based on the stability analysis for the intensified dam system of the tailings pond, taking into account the standard requirements for its overall stability.

Accumulation of Heavy Metals in the Needles of Scots Pine of the Semipalatinsk Pre-Irtysh Region and Burabay National Park

Relict bogs in the northeastern area of the Republic of Kazakhstan are located in close proximity to sources of heavy metal pollution – non-ferrous metal ore mining and processing facilities, and highways. Monitoring of heavy metal transport in the air by means of a bioindicator such as Scots pine (Pinus sylvestris L.) is relevant for preventing the damaging effects of heavy metals on the population living in this region. The purpose of this article is to study pine needles (Pinus sylvestris L.) on the territory of the Semipalatinsk Irtysh region and the Burabay National Park to identify the features of the accumulation of heavy metals carried by atmospheric air flows, depending on the age of its formation. To determine the content of chemical elements in needles of the first, second and third year of formation from six experimental plots mass spectrometry method ISO 17294-2׃2003 was used. Its results made it possible to conduct a primary analysis of the accumulation of heavy metals in the needles of Scots pine (Pinus sylvestris L.) depending on the year of its formation. General scientific methods were also used in the analytical selection of the scientific literature to formulate the objectives of the experiments and to compare the results obtained with those of other authors. Experimental studies revealed a direct correlation between the increase in concentrations of individual metals and the age of the needles. Furthermore, an increase in concentrations of individual chemical elements has been detected in the conifers of the second year of formation. The findings can be used for further scientific research on the use of pine needles (Pinus sylvestris L.) as a bioindicator, the impact of the heavy metal composition of the north-east of Kazakhstan on plant organisms, but also used in practice to monitor the state of the environment and the management of forests.

CFD-DEM simulation of raceway size and mechanical characteristics of industrial scale blast furnace

Abstract The raceway plays a crucial role in ensuring the stable functioning of the ironmaking blast furnace. It is the key site where the chemical reaction of coke combustion takes place, providing the necessary heat and reducing gas for the upper iron ore reduction process. Consequently, the size of the raceway serves as an essential indicator of the blast furnace’s operational condition. In this study, a mathematical model for the raceway of an industrial-scale blast furnace was established. Extensive innovation investigations were conducted to explore the characteristics pertaining to the raceway’s size. The simulation outcomes demonstrate that both the particle size and the inlet velocity exert significant influences on the raceway dimensions. Specifically, the height of the raceway is predominantly affected by the particle size, whereas the inlet velocity predominantly influences the depth of the raceway.

INNOVATIVE ENVIRONMENTALLY SAFE PROCESSES FOR RECOVERY OF RARE AND RARE-EARTH ELEMENTS FROM COMPLEX ORES OF COMPLEX MATERIAL COMPOSITION

Domestic and world tendencies of involvement in the processing of ores of rare and rare earth metals (REM) are shown. It is shown that the main direction of innovative activity is the development and application of modern breakthrough technologies for the complex processing of mineral raw materials with the production of high-quality products while minimizing environmental damage. The main deposits of rare and rare-earth metals are systematized from the standpoint of the content of the main components, concentrator minerals and the main enrichment methods. The main principal technological schemes of processing of some deposits of RM and REM in Russia (Lovozerskoe, Tomtorskoe, Afrikandskoe deposits) are given. The options for involving technogenic and off-balance raw materials in the processing in order to extract strategic metals are considered. It is substantiated that innovative environmentally friendly processes for the extraction of rare and rare earth metals from complex ores of complex material composition are being actively developed in Russia at present

Biohydrometallurgy: Paving the Way for a Greener Future of Mineral Processing in Indonesia

Biohydrometallurgy has been around since the 1960s, and it uses microorganisms to facilitate the extraction of metals. As environmental rules get stricter and the quality and complexity of ore available for processing decrease, this technology presents an alternate option for mineral processing. Several countries, including South Africa, Russia, Chile, Australia, the United States, China, Burma, New Zealand, Peru, Uzbekistan, and Ghana, have used this method commercially in copper processing plants and gold and silver processing plants. In Indonesia, this approach has neither been developed nor implemented on an industrial basis. In Indonesia, biohydrometallurgical processing is worth proposing as a solution to future mineral processing issues, particularly the problem of limited capital and low-grade ore processing. Globally, a significant amount of focus is placed on the investigation of biohydrometallurgy. However, only the Bandung Institute of Technology (ITB) does biohydrometallurgy-related research in Indonesia. This investigation began in 2009 for the extraction of nickel from laterite ores. Additional research has also been conducted on the extraction of metals such as copper and gold. The research findings thus far have generated an intriguing and highly potential outlook that can be scaled up through a pilot plant and industrialized in Indonesia.

An Integrated Analytics of PEM Electrolyzer and Steel Making

It is widely accepted that the hydrogen-water couple can elevate the green economy circuit if powered by renewable sources of energy. Proton-exchange membrane water electrolyzer (PEMWE) being a clean electrochemical device is expected to provide an amenable solution to the hydrogen-water nexus and act as an enabler to achieving decarbonization of the steel-making industry. In this work, we throw light on the performance of a PEMWE that feeds target hydrogen volumes to a direct iron ore reduction process. The response of the electrolyzer under the presence of a host of operational stressors and variable electricity input is delineated through a macroscale modeling framework. The techno-economics associated with specific energy consumption of the downstream steel-making pathways will be further discussed based on insights from a process cost model.

Plasma synthesis of various polymorphs of tungsten trioxide nanoparticles using gliding electric discharge in humid air: characterization and photocatalytic properties

A gliding electric arc (glidarc) discharge generates a low-temperature plasma at atmospheric pressure. When the discharge occurs in humid air as the feed gas, the chemistry of a glidarc plasma consists of in situ formation of HO° and NO° as the primary chemical species. Tungsten trioxide (WO3) nanoparticles were successfully prepared by exposure of a liquid precursor to glidarc plasma. The WO3 samples were calcined at three different temperatures (300 °C, 500 °C and 800 °C), resulting in different pure polymorphs: γ-WO3 (at 300 °C), β-WO3 (at 500 °C) and α-WO3 (at 800 °C) according to x-ray diffraction analysis. The identification of WO3 compounds was also confirmed by attenuated total reflection Fourier transform infrared spectroscopy analysis. Increase in the calcination temperature of WO3 induced a decrease in its specific surface area according to Brunauer–Emmett–Teller nitrogen physisorption analysis. The UV-visible results showed that the absorption bands of plasma-WO3 samples were more intense than those of WO3 samples obtained by a precipitation route, a classical method used for comparison. Consequently, this parameter can improve the photocatalytic properties of WO3 under visible light. The photodegradation (in sunlight conditions) of gentian violet, chosen as a model pollutant, confirmed the photocatalytic properties of plasma-WO3 samples. This novel synthesis method has great potential to improve the efficiency of advanced tungsten trioxide-based functional material preparation, as well as in pollution-reducing and energy-saving tungsten extractive metallurgy.

Estimation of Energy Consumption for Concentrate Process of Tungsten Ore towards the Integration of Renewable Energy Sources in Mongolia

It is important to estimate the energy required in ore processing to select the most affordable and efficient energy system for the integration of renewable resources into the mining industry. In the present work, the energy consumption for the concentrate of tungsten ore in Mongolia was theoretically predicted based on operational variations (particle size and the hardness of the tungsten ore) and different equipment. The energy was in the range from 0.48 to 1.32 kWh/t for the crushing stage, and a cone crusher was more suitable than a jaw crusher due to the particle size of feed material and product. The required energy in the grinding stage was from 6.22 to 11.88 kWh/t using a SAG mill or from 3.04 to 7.39 kWh/t using a ball mill. The further separation by a flotation consumed 4.83 kWh/t or by a shaking table consumed 1.29 kWh/t. The maximum energy consumption per hour for the whole process was estimated to be 2–3 MW, which was better to integrate with a hybrid renewable energy system. The sizing method Power Pinch Analysis was used to estimate the electric supply based on the combination of wind, biomass and solar resources, which was sufficient for the demand from the predicted range of energy.

New insights into double roll crushing

Double roll crushing is a comminution principle that has already been deployed for more than 100 years. It is known for high throughputs of sometimes sticky materials such as overburden. However, its applicability for ore and hard rock processing has been underestimated in recent decades. The presented research results are suitable for drawing attention again for these applications to a robust and reliable group of comminution machines – the double roll crushers (DRC).The paper presents results of extensive investigations exploring the influences of compressive strength, roll peripheral speed, feed particle size distribution, and single large oversized lumps on throughput of a toothed double roll crusher. A pilot-scale crushing plant in a quarry was deployed to test the crusher with limestone, andesite, and diabase. It can be shown that, contrary to other crusher types, within the physical limits of the machine, the throughput of DRC is barely influenced by the feed material’s compressive strength, while the feed particle size distribution or even single oversize lumps in the feed may have a substantial impact.

Metal/metalloid bioconcentration dynamics in fish and the risk to human health due to water contamination with atmospheric particulate matter from a metallurgical industrial area

Settleable atmospheric particulate matter (SeAPM) containing a mixture of metals, including metallic nanoparticles, has increased throughout the world, and caused environmental and biota contamination. The metal bioconcentration pattern in Nile tilapia (Oreochromis niloticus) was evaluated during a 30-day exposure to 1 g L−1 SeAPM and assessed the human health risk from consuming fish fillets (muscle) based on the estimated daily intake (EDI). SeAPM was collected surrounding an iron ore processing and steel industrial complex in Vitória city (Espírito Santo, Brazil) area. Water samples were collected daily for physicochemical analyses, and every 3 days for multi-elemental analyses. Metal bioconcentrations were determined in the viscera and fillet of fish every 3 days. The elements B, Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Ag, Cd, Pb, Hg, Ba, Bi, W, Ti, Zr, Y, La, Nb, and Ce were analyzed in SeAPM, water, and fish using inductively coupled plasma mass spectrometry. The metal concentration in SeAPM-contaminated water was higher than in control water. Most metals bioconcentrated preferentially in the fish viscera, except for the Hg and Rb, which bioconcentrated mostly in the fillet. The bioconcentration pattern was Fe > Al > Mn > Pb > V > La > Ce > Y > Ni > Se > As > W > Bi in the viscera; it was higher than the controls throughout the 30-day exposure. Ti, Zr, Nb, Rb, Cd, Hg, B, and Cr showed different bioconcentration patterns. The Zn, Cu, Sr, Sn, Ag, and Ta did not differ from controls. The differences in metal bioconcentration were attributed to diverse metal bioavailability in water and the dissimilar ways fish can cope with each metal, including inefficient excretion mechanisms. The EDI calculation indicated that the consumption of the studied fish is not safe for children, because the concentrations of As, La, Zr, and Hg exceed the World Health Organization's acceptable daily intake for these elements.

Effect of chemical environment on copper tailings reinforced by microbially induced carbonate precipitation

The accumulation of large amounts of tailings produced in the beneficiation process of ores is one of the main challenges for mining industry related to their retention in tailings ponds and the potential hazard of tailings dams’ failure. To enhance stability of tailings dams, microbially induced carbonate precipitation (MICP) has emerged as a novel technique for tailings treatment. However, the intricate chemical environment within tailings ponds affects the growth of microorganisms and can adversely impact the efficiency and effectiveness of MICP. This study investigates for the first time the factors that influence the growth of Sporosarcina pasteurii in a copper tailings pond characterized by weak acidity and the presence of copper ions. The adverse effects of the chemical environment in copper tailings ponds on MICP are investigated through mechanical tests and microscopic analyses on four groups of MICP-reinforced copper tailings. The results revealed that copper ions inhibited the growth of bacteria, while pH had an insignificant effect on bacteria. Hence, copper ions are identified as the main factor that weakens the reinforcing effect of MICP on copper tailings. Even though the weakly acidic environment has been shown to have a minor impact on the performance of MICP-reinforced copper tailings, maintaining the acid resistance of the reinforced tailings is crucial for ensuring long-term reinforcement effectiveness. It was also found that increasing the concentration of the bacterial solution and applying it in multiple injections, while controlling the pH of the cementation solution, could enhance the survival rate and activity of bacteria and improve the carbonate sedimentation environment. This would strengthen the reinforcing effect of MICP. The results demonstrated that MICP has promising potential for tailings treatment, but it is essential to address the adverse effects of the chemical environment in tailings ponds. The findings from this study provide valuable reference data for subsequent field experiments and engineering practices and facilitate the application of biomineralization in tailings ponds.

Study on the treatment of cyanide gold extraction wastewater by persulfate-electrochemical oxidation

The cyanide gold extraction wastewater from a gold smelter was treated using a persulfate-electrochemical oxidation (PS-EO) coupling process. The optimal process conditions and significance level of each factor were determined using orthogonal experiments, and the precipitates and cathodic precipitates in the system were analyzed and characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), and the oxidation removal reaction mechanism of cyanide was further explored. The results showed that voltage, time and PS concentration were the main influencing factors of the cyanide removal extent. When the voltage was 5 V, PS concentration 0.5 g L–1, pH 7, plate spacing 2.5 cm and reaction time 240 min, the removal extents of total cyanide (CNT), free cyanide (CN–), Cu and Zn ions in wastewater reached 98.33 %, 100 %, 99.53 % and 98.86 %, respectively. The removal of cyanide was mainly attributed to the indirect oxidation by SO4•–, •OH and O2•– active radicals produced by activated PS and the direct oxidation of S2O82–. The contribution rate of S2O82– direct oxidation was 42.38 %. The oxidation contribution rates of SO4•–, •OH and O2•– active free radicals were 15.75 %, 29.33 % and 12.54 %, respectively. Compared with simple PS and EO treatment processes, the PS-EO combined process reduced the amount of oxidants and helped to improve the current density of the system, as well as the generation of active free radicals such as SO4•–, •OH and O2•–. Additionally, after PS-EO treatment, there were almost no precipitates such as Zn(CN)2, CuCN, Zn(OH)2 and Cu(OH)2 produced in the wastewater. The cyanide ions in complex ions such as Cu(CN)32– and Zn(CN)42– were completely oxidized to N2 and CO2, and then under the influence of an electric field, the released Cu2+ and Zn2+ ions were directed to migrate to the cathode and precipitate.Finally, the treated wastewater could be directly returned to the grinding or leaching the ore process, thus achieving the goals of being harmless and utilizing cyanide wastewater resources.