Mark I. Pownceby

The Commonwealth Scientific and Industrial Research Organisation | CSIRO · Mineral Resources

The high-temperature, carbothermal treatment of REE-bearing monazite concentrates to remove P in preparation for REE extraction was investigated. The study comprised a series of thermodynamic assessments followed by laboratory-scale experiments at 1400 °C and 1500 °C at 1 atm pressure. Two monazite concentrates with different compositions were used...

The use of controlled pulp potential (Eh) during froth flotation to separate two nickel sulfide minerals, millerite (NiS) and pentlandite (Fe4.5Ni4.5S8), and thereby produce separate millerite and pentlandite products was investigated. Batch single mineral flotation tests were performed on a high-quality nickel sulfide specimen from Canada, grading...

The Bangladesh Government is examining the feasibility of mining river sands in Bangladesh as potential sources of heavy minerals (HM) for export and/or domestic use. Since 2010 research at BCSIR and CSIRO has focussed on the HM potential of the northern Brahmaputra River and in 2022 a pilot plant was constructed at Joypurhat in Bangladesh to devel...

Carbon-rich sources, such as coal and carbon monoxide gas, have been extensively used in the metal industry as the reducing agent of metal oxides and as the energy source for metal production. Consequently, the extractive metal sector contributes to approximately 9.5% of global greenhouse gas emissions. Hydrogen gas offers a promising alternative t...

The steel industry is one of the main contributors to global greenhouse gas emissions, responsible for about 7 to 9% of the world’s total output. The steel sector is under pressure to move toward net-zero emissions by reducing its consumption of coke as the main method of reducing iron-rich feed materials to iron. Due to its well-developed synthesi...

Decarbonization in the iron and steelmaking industry is vital for achieving a net-zero economy as it contributes 7% to 10% of global CO2 emissions. Considering the technology readiness, hydrogen-based direct reduction is amongst the most promising route for producing green steel despite some technical issues in storing, distributing, and transporti...

CaO- and MgO-rich fly ash derived from low-grade coals is typically discarded due to its incompatibility with existing large-scale valorisation technologies. This study demonstrates the potential of such low-grade fly ash as a substitute for flux and MgO sources in the iron-ore sintering process, a critical step in producing feedstock to yield ~1 G...

Using the X-ray diffraction (XRD) patterns collected on the products of laboratory furnace experiments performed on a synthetic iron ore sinter mixture with composition 77.36 % Fe2O3. 14.08% CaO, 3.56% SiO2 and 5.00% Al2O3, it is demonstrated that the previously reported Fe-rich SFCA phase has the same crystal structure as triclinic SFCA-III. There...

Boron nitride nanotubes (BNNTs) have been extensively studied for hydrogen storage, sensing, and radiation shielding applications. The deformation behaviors of pristine, defective, and H 2-encapsulated closed-end armchair BNNTs and BNNT-carbon nanotube (CNT) heterostructures are investigated using molecular dynamics employing the ReaxFF interatomic...

The increasing demand for rare earth elements (REEs) has led to the exploration of mining tailings as a potential secondary source. This study offers novel insights into the recovery of REEs from Fe-rich mine tailings sourced from a weathered carbonatite deposit. The REEs were recovered by selectively removing Fe impurities after acid-leaching. The...

The global increase in electric vehicles (EVs) uptake accelerates the number of End-of-life (EOL) lithium-ion batteries (LIBs) to be managed and recycled. EOL LIBs contain valuable metals that may potentially be recovered for re-use. In this study, aluminum 7075 waste chips were used as a reductant to separate Li and Co from LiCoO2 (the most common...

Ternary master slags based on the CaO-Al2O3-SiO2 system with CaO/SiO2 (C/S) ratio 0.3-1.0 were doped with 5-20 wt pct of anhydrous borax (Na2B4O7) to study the phase equilibria of the quinary CaO-Al2O3-SiO2-Na2O-B2O3 slag system within the temperature range 1050-1350°C. This research uses the well-known method of high temperature equilibration of s...

Australia has large reserves of limonite and clay-based laterites that are currently underutilized. This review summarizes the latest nickel laterite upgrading studies reported in the literature which use physical beneficiation – only studies reported after the most recent review in 2015 included – as well as high-temperature methods involving oxid...

In-situ resource utilization (ISRU), particularly the extraction and production of structural metals from Martian regolith, is crucial for supporting further exploration on Mars. This study proposes that carbothermal reduction is the most feasible technique to produce metals on Mars considering the accessibility of CO2 (96%) in the atmosphere as a...

The CSIRO ore classification scheme for Pilbara ores was used as a reference frame to target recognisable ore types/textures with potentially elevated phosphorus content for detailed analysis. Particles of each individual ore texture were separated from a Brockman high-P ore and each class was characterised using methods including XRF, XRD, EPMA an...

Sticking and breakage of iron ore pellets during high temperature reduction can result in several operational challenges during shaft furnace ironmaking. With the shift to H2-based DRI processes and decreasing iron ore quality, this issue becomes more prominent. It is therefore important to understand how the iron ore chemistry and mineralogy affec...

Naturally occurring goethite is typically associated with impurities such as SiO2, Al2O3 and P2O5. These may be found with goethite through mechanisms including direct substitution or coprecipitation of nanocrystalline phases. Understanding P incorporation in goethite has significant implications for Australia's iron ore industry as it lowers their...

The relative influences of sinter mineralogy, sintering temperature, solid and pore macro- and microstructure on iron ore sinter physical strength are not yet fully understood. Whilst a range of analysis techniques have been used by researchers to evaluate sinter physical properties and sinter mineralogy, none have been able to directly link sinter...

Steelmaking has a significant contribution in producing greenhouse gases and there is a worldwide push towards decarbonising the process. One of the approaches to reduce CO2 emissions is to use hydrogen in the blast furnace (BF) as the reductant gas. However, hydrogen reduction is an endothermic reaction, bringing changes to the temperature distrib...

The large investment into establishing human habitation on the moon, such as the Artemis program, is pushing development of methods for processing of lunar regolith to produce a range of useful materials, particularly ceramics and metals. There is wide recognition that the materials processes developed should rely as much as possible on the resourc...

Printed circuit boards (PCBs) from antiquated electronic goods were processed by a pyrometallurgical route to produce and separate alloy and slag phases. The process involved initial size reduction of PCBs, followed by pyrolysis at 500 C for 6 h and finally smelting of the solid materials in an electric furnace. A preliminary smelting test was perf...

Hydrogen is an alternative reductant to replace carbon for the production of metals. Reduction by hydrogen has advantages compared to carbothermic reduction, such as faster reaction rate and cleaner by-product (water vapor). This study investigated the application of hydrogen reduction for recycling and recovering cobalt and lithium from Li-ion bat...

Sulphide tailings are a major environmental concern due to acid mine drainage and heavy metal leaching, with costly treatments that lack economic benefits. Reprocessing these wastes for resource recovery can address pollution while creating economic opportunities. This study aimed to evaluate the potential for critical mineral recovery by character...

A characterization study of chromite ore from South Africa was conducted using bulk assays, X-ray diffraction, optical, scanning electron microscopy (SEM), automated electron probe microanalysis (EPMA) and quantitative evaluation of mineral by scanning electron microscopy (QEMSCAN) mineralogical techniques, and quantitative EPMA. The aim was to ide...

The current interest in space-based mineral and metal extraction technologies, and the increased likelihood of establishing research facilities on the lunar surface, provides a strong impetus for high vacuum metallurgical research. The current work examines the viability of a thermal dissociationThermal dissociation process for metal and metal oxid...

Rare-earth-elements (REE)Rare-earth-elements (REE) can be used as alloying agents to improve the properties of aluminumAluminum alloys. REE are often added in the metallic form to produce the alloys, but the high cost of REE metals makes the alloys expensive thus limiting their application. An alternative way to make REE-Al alloys is by reacting RE...

An understanding of the reaction phases formed during the high-temperature oxidationHigh-temperature oxidation of rare earthRare earth permanent magnets is vital for developing appropriate strategies for their pyrometallurgy-based recyclingRecycling processes aimed at the concentration and potential recovery of the rare earthRare earth elements. Th...

When considering the extraction of metals from lunar regolith for use in space, one reductive method of interest is vacuum thermal dissociation. Given the high vacuum environment on the Moon, the sub-liquidus operation of such a process, i.e., sublimation, warrants investigation. In the current work, the kinetics of the vacuum sublimation of the mo...

The use of electrical appliances and electronic gadgets has been increasing at a fast rate in Bangladesh mainly because of the increased economic growth in recent years. With this growing demand, the generation of waste electrical and electronic equipment (WEEE) is increasing since all items end up in the e-waste stream at the end of their life. Th...

Lime Magnetite Pellets (LMP) have the potential to lower the carbon footprint of conventional iron ore feedstocks such as pellets and sinters. LMP are produced by directly indurating magnetite-limestone pellets under mildly reducing conditions at temperatures of about 300 °C lower than used in the existing magnetite pelletising process. The resulti...

The trends and efficacy of ultrasonic pre-treatment before desliming high phosphorus Australian iron ore fines was investigated in the presented fundamental study. The −1 mm iron ore fines (57.5 wt% Fe, 2.47 wt% Si, 2.15 wt% Al, 0.132 wt% P) were subjected to sonication while the ultrasonic power, duration and pumping direction were varied. Sonicat...

The presence of Ca-ferrite and silico-ferrite-of-calcium-and-aluminium (SFCA) bonding phases is thought to be crucial to maintain sinter quality due to their high reducibility and strength levels. However, new evidence suggests that porosity might be an equally important factor controlling reducibility, in addition to mineralogy. This work aims to...

The removal of chromium-containing impurities, such as chrome spinel (ZCr2O4 where Z = Fe, Mg, Mn) from ilmenite (FeTiO3) concentrates through selective sulphidation, has been investigated by the authors. Laboratory experimental studies using sulphur added to ilmenite concentrates under Becher-type reduction conditions showed it is possible to sele...

The target basicity of iron ore sinter is set by blast furnace slag composition requirements, and therefore varies with the proportion of acid burden such as lump iron ore and pellets. Increasing the lump proportion of the burden will increase the target sinter basicity. The mineralogy of sinter produced with a range of basicity between 1.0 and 3.0...

The phase equilibria in the CaO-Al2O3-SiO2 ternary system doped with around 5, 10, 15 and 20 wt% B2O3 was studied using a high-temperature equilibration followed by rapid quenching technique. Fifteen samples with CaO/SiO2 (C/S) ratios of 0.3, 0.6 and 1.0 containing 15.6-19.1 wt% Al2O3 were equilibrated at a range of temperatures close to predicted...

A Floatex density separator was used to reduce the silica and alumina contents of a low-grade iron ore plant reject sample from the Pilbara region in Western Australia to produce a high-quality iron ore concentrate suitable for use in sinter and pellet blends. From a −2.0 mm head sample containing 49.42 wt% Fe, 12.77 wt% SiO2 and 4.90 wt% Al2O3, a...

INTRODUCTION Electronic waste (e-waste) is one of the fastest growing waste streams across the world with a global generation of more than 50 Mt every year (Forti et al, 2020). Rapid technical advancement together with growing demand for modern electronic and electrical equipment (EEE) is contributing to shortages of key metals and minerals. It is...

Iron ore sinter quality has a strong influence on the blast furnace productivity. Conventional wisdom says that the presence of the Silico-Ferrite-of-Calcium-and-Aluminium (SFCA) phases is crucial to maintaining sinter quality due to its reducibility. However, some new evidence suggests that porosity might be the main factor controlling reducibilit...

The synthesis and characterisation of SFCA-I compounds has been performed. SFCA-I is one of the key bonding phases in iron ore sinter, influencing physical properties such as strength, reducibility, and strength degradation during reduction. The results reported herein extend the understanding of the solid solution limits of the SFCA-I phase, with...

The phase evolution during heating of two Al2O3-free mixtures designed to form the SFC iron ore sinter bonding phase was investigated using in-situ X-ray diffraction over the temperature range 293–1623 K. Results showed that during heating at an oxygen partial pressure of 5 × 10⁻³ atm, SFC formation was preceded by the formation of γ-Ca4Fe14O25 and...

The following review is Part III of a series concerned with the direct hydrometallurgical processing of nickel sulfide flotation concentrates. In the first part of this series, piloted leaching processes and commercial nickel sulfide operations that employed direct hydrometallurgical processing were comprehensively reviewed. In the second part of t...

The following review is the second part of a series concerned with the direct hydrometallurgical processing of nickel sulfide flotation concentrates. In the first part of this series, piloted leaching processes and commercial nickel sulfide operations which employed direct hydrometallurgical processing were comprehensively reviewed. In Part II of t...

High-arsenic copper flotation concentrates, in which the major arsenic-bearing mineral was tennantite, were leached with an alkaline sulphide system. At a pulp density of 5 wt% solids with 100–150 g/L Na2S and 50 g/L NaOH, over 91 wt% As was dissolved within 2 h at 100°C. From concentrates containing 3.4–4.9 wt% As, leach residues containing <0.5 w...

The extraction of nickel (Ni) from sulfide resources commences with flotation to produce a concentrate which is then smelted to produce a nickel-enriched phase called matte, and further refined to produce pure Ni products as well as by-products, such as cobalt (Co), copper (Cu) and precious metals. However, the traditional concentrate smelting-matt...

This work is part of a larger project that investigates the relationship between the sinter mineralogy and porosity on important sinter properties, notably strength and reducibility, by developing a fundamental understanding of how porosity is created in simple sinter systems. The aims of this work are: • To create simple sinter system analogues us...

The present study describes results obtained from the chemistry of detrital heavy minerals i.e. pyroxene, amphibole, biotite, garnet, epidote and Fe-Ti oxides in fluvial sediments of the northern Brahmaputra River (Bangladesh) with an aim to determine conditions of their petrogenesis and provenance. The primary and secondary genera of ferromagnesia...

The relative effects of dolomite and serpentine/olivine as MgO flux sources on the formation of SFCA and SFCA-I iron ore sinter bonding phases during heating was investigated using in situ synchrotron X-ray diffraction. Results showed that a sinter mix containing serpentine/olivine as the primary source of MgO is more likely to form high quality si...

A study into the possible separation of feldspar from quartz in a Bangladesh river sand sample was undertaken with the aim of producing a high-grade quartz product for potential use in glassmaking. Flotation was used to upgrade two river sand concentrates, with sizings of +250 µm and −250 µm, from the Brahmaputra River. Feldspar was floated from qu...

This article analyses Bangladesh export–import data to quantify historically generated e-waste from four types of discarded electronic devices (mobile phones, TVs, tablets, and computers/laptops) and uses the trends to predict the generation of e-waste from these devices up to 2030. From this data, together with estimated redundancy rates, printed...

Heavy mineral (HM) concentrations in sand bar deposits of the Meghna River were evaluated using optical microscopy, X-Ray Diffraction (XRD), X-Ray Fluorescence spectrometry (XRF), Scanning Electron Microscopy (SEM) and Electron Probe Microanalysis (EPMA) to determine the mineralogy, geochemistry and likely source rocks of the sands, and to examine...

The effect of low-pressure environments on metal compound stability is a well-known but rarely utilised phenomenon, even though reduction processes operating at subatmospheric pressures offer significant benefits in terms of the energy requirements for metal compound reduction. At industrial scales, some vacuum metallurgical processes such as silic...

As higher-grade ores become depleted, there will be a greater focus on developing suitable beneficiation strategies to treat low-grade hematite-goethite ores containing higher levels of impurities such as silica and alumina. The processes selected to reduce impurity levels of these lower-grade iron ores will depend on the ore mineralogy and a thoro...

The kinetics and mechanisms of carbothermic reduction of a complex Kalimantan weathered ilmenite (FeTiO3) using palm kernel biomass were investigated in the temperature range 1273–1473 K. The study included a combined thermodynamic assessment together with reduction experiments. Results were contrasted with data from similar experiments conducted u...

The current practice of magnetite ore agglomeration involves high temperature oxidation roasting (typically at 1200-1350°C) of magnetite to hematite phase in order to improve the strength and reducibility of pellets. The requirement to pre-oxidise the magnetite before introduction to an ironmaking plant increases the CO2 emissions generated during...

The use of concentrated solar flux for high temperature metallurgical applications is a well-researched area with several reported literatures on solar calcination and metal oxide reduction. This paper presents two such processes with potential to reduce the carbon footprint from ironmaking through using concentrated solar flux. The first process i...

Global demand for iron and steel has increased substantially over the past 20 years and there has been a greater focus on developing suitable processing options to treat low-grade hematite-goethite ores containing higher levels of silica and alumina impurities. The processing applicable to reduce the impurity levels in these lower-grade iron ores d...

Characterisation of SFCA in IRON ORE SINTER.

Charcoal produced from Syzygium Zeylanicum (local name: Yakada Maran = iron killer) trees were widely used in ancient Sri Lankan iron smelting practices. In this study, relict charcoal from Syzygium Zeylanicum tree trunks, branches and leaves were analysed for the first time. Unusually high concentrations of calcium oxalate (CaC2O4.H2O-CaOX) crysta...

High-temperature carbothermal reduction experiments with graphite powder were conducted to assess the dephosphorization behaviour of Malaysian monazite concentrate. Thermodynamic analysis of the possible dephosphorization reactions was conducted to evaluate the feasibility of the carbothermal reduction of the monazite phases. The effects of tempera...

The lunar surface is extremely harsh and current mineral processing and metal extraction technologies are not adequately equipped to address this environment. In this paper we review the metals available for extraction and conditions at the lunar surface, and analyse the challenges associated with comminution, beneficiation, and metal extraction op...

The lunar surface is extremely harsh and current mineral processing and metal extraction technologies are not adequately equipped to address this environment. In this paper, we review the metals available for extraction and conditions at the lunar surface, and analyze the challenges associated with comminution, beneficiation, and metal extraction o...

In-Situ Resource Utilization (ISRU) of water assets from the lunar surface, especially from the volatile-rich polar regions, is a topic of significant current research. However, the term ISRU can encompass a much wider variety of potential resources and relevant extraction technologies. In a novel approach, rather than treating an extra-terrestrial...

Abstract:Bangladesh’s heavy minerals deposits in river systems remain largely unexplored withpast research restricted to beach placer deposits along the south-eastern coastline of the country.In this study, 64 samples were collected from stable sand bars from the northern BrahmaputraRiver. The average total heavy minerals (THM) from all sample site...

The iron and steelmaking industry is actively seeking to reduce its overall carbon footprint with major research and investment directed towards fossil fuel-free steelmaking. In this paper, we present a novel iron ore agglomeration process that produces a Lime Magnetite Pellet (LMP) feed using concentrated solar flux as the energy source that signi...

Microwave-assisted reduction roasting of a goethite-rich, reject iron ore waste stream (−2 mm) was used to produce a high-grade concentrate. Reduction roast experiments were conducted at 370 °C, 450 °C, 600 °C and 1000 °C under gas atmospheres of 30:70 and 40:60 CO/CO2, with a soak time of 20 min. Goethite was converted to hematite above 370 °C und...

This study presents a theoretical pathway to the production of sodium and potassium metal from lunar regolith at ambient lunar conditions via the selective thermal decomposition of oxides in the regolith using concentrated solar energy. The proposed process for the recovery of the products is systematically evaluated via thermodynamic modelling bas...

Sinter quality is a key element for stable blast furnace operation. Sinter strength and reducibility depend considerably on the mineral composition and associated textural features. During sinter optical image analysis (OIA), it is important to distinguish different morphologies of the same mineral such as primary/secondary hematite, and types of s...

The oxidation behaviour of rare earth permanent magnets contributes significantly to the understanding and efficiency of their high temperature recycling processes. The current paper evaluated the high temperature oxidation kinetics of end-of-life Ni/Cu/Ni coated NdFeB rare earth permanent magnets at 973-1473 K under ambient air conditions. The gen...

Phase equilibria of CaO-Al2O3-SiO2-Na2O slags were studied by thermal equilibration and quenching. The primary phases of the quenched slags were identified, and their equilibrium compositions determined by electron probe microanalysis. Liquidus temperatures of the slags were bracketed within an uncertainty of ± 10–20°C. Anorthite (CaO·Al2O3·2SiO2),...

The behaviour of rare earth permanent magnets during oxidation profoundly determines the high temperature recycling processes. This current study analysed the microstructure evolution of end-of-life, coated NdFeB rare earth permanent magnets after oxidization at 973-1473 K under ambient air conditions. Four distinct categories of microstructure evo...

The recovery of valuable and critical metals from electronic wastes (ewaste) via the pyrometallurgical route has some challenges including high processing temperatures. Designing appropriate slag systems based on the major elemental components in e-waste could bring operational advantages by lowering the liquidus temperature. In this study, the qua...

We explore the role of various solution environments – chloride brines, acid mine drainage (sulfate) and groundwater (carbonate), as well as pore pressure in producing secular disequilibrium among the various radionuclides (RN) in the U-decay series upon leaching of uraninite – the most abundant U-ore and a widespread accessory mineral in U-rich ro...

Space Resource Utilisation (SRU) is an emerging field of research that is rapidly expanding in scope. Solar thermal processing technology poses multiple significant advantages for SRU activities on the lunar surface. There are also some significant challenges related to the use of solar power that need to be addressed. Space missions currently lau...