Separation and recovery of iron from a low-grade carbonate-bearing iron ore using magnetizing roasting followed by magnetic separation

Review on the chemical reduction modelling of hematite iron ore to magnetite in fluidized bed reactor

Steel production is considered as one of the major backbones of many economies. Though blast furnace is the primary route of steel production, the industries are willing to alternatives technologies such as the high temperature-controlled conversion of hematite to magnetite. The geological and mineralogical characteristics of the low-grade iron ores possess difficulties in their conventional enrichment. The literature concludes the advantages of high-temperature conversion in terms of easiness in downstream operations caused by decreased hardness and increased magnetic susceptibility of magnetite. The modelling work has been primarily focused on the direct reduction of iron ore to metallic iron. The present compilation discusses the scientific and engineering developments on the reduction-roasting of iron-ore followed by the CFD–DEM modelling and simulation work performed to reduce iron ore to magnetite. It provides a comprehensive review of the experimental and industrial progress done in the area.

Bioelectrochemical systems-based metal recovery: Resource, conservation and recycling of metallic industrial effluents

Metals represent a large proportion of industrial effluents, which due to their high hazardous nature and toxicity are responsible to create environmental pollution that can pose significant threat to the global flora and fauna. Strict ecological rules compromise sustainable recovery of metals from industrial effluents by replacing unsustainable and energy-consuming physical and chemical techniques. Innovative technologies based on the bioelectrochemical systems (BES) are a rapidly developing research field with proven encouraging outcomes for many industrial commodities, considering the worthy options for recovering metals from industrial effluents. BES technology platform has redox capabilities with small energy-intensive processes. The positive stigma of BES in metals recovery is addressed in this review by demonstrating the significance of BES over the current physical and chemical techniques. The mechanisms of action of BES towards metal recovery have been postulated with the schematic representation. Operational limitations in BES-based metal recovery such as biocathode and metal toxicity are deeply discussed based on the available literature results. Eventually, a progressive inspection towards a BES-based metal recovery platform with possibilities of integration with other modern technologies is foreseen to meet the real-time challenges of viable industrial commercialization.

Efficient iron recovery from iron tailings using advanced suspension reduction technology: A study of reaction kinetics, phase transformation, and structure evolution

Recycling iron tailings is significant for environmental security and resource recovery, as they contain iron-rich minerals. Given the complex composition of iron minerals and the low grade of iron present in the tailings, innovative suspension roasting-magnetic separation (SRMS) technology was proposed to treat iron tailings that would separate out the iron minerals for recovery. In this study, the reduction kinetics, phase transformation, and structure evolution of the iron tailings were investigated to explain the mechanism behind magnetite production from iron tailings. These studies were conducted using chemical analyses, X-ray diffraction, Brunauer-Emmett-Teller specific surface area, and scanning electron microscopy. The results showed that high temperatures during the suspension reduction process were conducive to improving the reduction rate of the iron tailings. The best kinetics model for this reduction reaction of iron tailings is the P1 model, which demonstrated a linear increase in the conversion degree with the extension of the reaction time. The corresponding mechanism function was f(α) = 1, the apparent activation energy (E_α) was 51.56 kJ/mol, and the kinetics equation was k = 3.14exp(- 51.56/RT). Using the SRMS technology, magnetite gradually formed from hematite, starting at the outer particle layers and moving inward toward the core. The microcracks and pores in the surface of the particles increased, which promoted CO penetration into the particles where it reacted with the hematite. Our results provide important insight into the efficient and clean recycling of iron tailings.

Recovery of γ-Fe2O3 from copper ore tailings by magnetization roasting and magnetic separation

To comprehensively reuse copper ore tailings, the recovery of γ-Fe2O3 from magnetic roasted slag after sulfur release from copper ore tailings followed by magnetic separation is performed. In this work, after analysis of chemical composition and mineralogical phase composition, the effects of parameters in both magnetization roasting and magnetic separation process with respect to roasting temperature, residence time, airflow, particle size distribution, magnetic field intensity, and the ratio of sodium dodecyl sulfonate to roasted slag were investigated. Under optimum parameters, a great number of γ-Fe2O3 is recycled with a grade of 66.86% and a yield rate of 67.21%. Meanwhile, the microstructure, phase transformation and magnetic property of copper ore tailings, roasted slag, and magnetic concentrate are carried out.

Advances in mineral processing technologies related to iron, magnesium, and lithium

Exploitation and utilization of mineral resources have played a vital role in China’s rapid economic developments. Although the history of mineral processing is quite long, technologies in this field have varied with the changes of market demands. This is particularly the case for minerals whose high-grade deposits are depleting. The aim of this review is to present our recent efforts on developing new routes for the utilization of low-grade minerals, such as iron ores and brine-containing lithium. The emphasis on the two minerals lies in the fact that iron plays a vital role in modern-day civilization and lithium is a key component in electric vehicles for transportation. Furthermore, the utilization of magnesium chloride reserves, one of the largest wastes in western China, as raw materials for fabrication of functional materials is also included in this review.