Process Flowsheet Research Articles

Characterization and Processing of Low-Grade Middle Group 2 Chromite Ore by Gravity Shaking Table and a Comparative SLon Magnetic Separation: A Case Study

Chromite is considered a strategic mineral in the global economy. It is mainly used as an essential raw material in the production of stainless steel and other metal alloys due to its corrosion and heat resistance properties. High-grade chromite resources are gradually depleting; with the increasing chromite demand in metallurgical applications, studies have focused on exploring low-grade and alternative chromite sources. This study proposes a cost-effective processing flowsheet for the low-grade middle group 2 (MG2) chromite layer, a poorly explored chromatite seam within the South African bushveld igneous complex (BIC). The study involved mineralogical characterization followed by gravity and magnetic separation of the low-grade MG2 ore at 18.18% Cr2O3. Characterization by XRD and Auto-SEM revealed that the ore mainly consists of pyroxene, chromite, and feldspar, with other minerals in trace quantities. The gravity separation test by shaking table upgraded the chromite (Cr2O3) to 42.0% at high chromite recoveries, whereas the laboratory Slon wet high-intensity magnetic separation method (SLon WHIMS) upgraded the chromite in the feed to 42.95% grade at lower chromite recoveries. Desliming the sample before the gravity and magnetic separation tests significantly improved the separation. The magnetic separation tests further demonstrated that chromite within the MG2 layer is sensitive to magnetic separation due to its high iron content. The adapted flowsheet is proposed as a cost-effective flowsheet for processing the low-grade MG2 layer. The flow sheet can be optimized by conducting the SLon WHIMS tests at high intensities followed by fine gravity tests by spiral circuits to maximize the chromite recovery while achieving commercial chromite grades and a Cr:Fe ratio greater than 1.5.

Process Synthesis, Design and Techno-Economic Assessment of Malonic Acid Production

This work focuses on the design and techno-economic evaluation of an industrial facility for the production of malonic acid. The raw material utilized is commercial glucose syrup with a concentration of 95%. Based on a patent of Lygos, Inc., an innovative biotechnology research company, this study presents a comprehensive synthesis, design, and simulation framework for the production of malonic acid through oligosaccharide fermentation. An integrated process flowsheet is proposed and simulated using SuperPro Designer™. The analysis indicates that for an installation capacity of about 8000 MT/yr of the final product with a purity of 99.5%, the production cost is estimated at USD 7.92/kg. A comprehensive study of the capacity’s impact on economics reveals that this cost could decrease to as low as USD 6.05/kg. A parametric analysis and optimization conducted at the flowsheet level identifies opportunities for further reducing production costs, laying the groundwork for a potential decrease in the product’s selling price.

Design and optimization of reaction-separation-recycle systems using a pseudo-transient continuation model

The reaction-separation-recycle (RSR) systems are an important part of chemical processes. Due to the interaction between reaction and separation sections, the behavior of RSR processes becomes highly complex and non-linear, posing different challenges for their design and optimization. The purpose of this study is to design and optimize RSR processes for irreversible liquid phase reaction systems using the pseudo-transient continuation (PTC) approach within an equation-oriented programing environment. This approach was applied to investigate one binary system and four ternary systems. The differential-algebraic models of the proposed process flowsheets were solved until the steady-state conditions were reached. The tray bypass efficiency method was incorporated into the PTC to circumvent the need for discrete optimization. The results demonstrated that in those cases where the product was heavier than the reactants, employing a stripping column was more economical than using a conventional distillation column for both the binary and ternary systems. In the ternary systems with two recycle streams, when the product was the intermediate component in terms of boiling point, the utilization of a divided-wall distillation column (DWC) resulted in a total annual cost saving of 35 % and 41 % compared to direct and indirect separation methods, respectively.

Aspects of Spodumene Lithium Extraction Techniques

Lithium (Li), a leading cathode material in rechargeable Li-ion batteries, is vital to modern energy storage technology, establishing it as one of the most impactful and strategical elements. Given the surge in the electric car market, it is crucial to improve lithium recovery from its rich mineral deposits using the most effective extraction technique. In recent years, both industry and academia have shown significant interest in Li recovery from various Li-bearing minerals. Of these, only extraction from spodumene has established a reliable industrial production of Li salts. The current approaches for cracking of the naturally occurring, stable α-spodumene structure into a more open structure—β-spodumene—involve the so-called decrepitation process that takes place at extreme temperatures of ~1100 °C. This conversion is necessary, as β-spodumene is more susceptible to chemical attacks facilitating Li extraction. In the last several decades, many techniques have been demonstrated and patented to process hard-rock mineral spodumene. The objective of this review is to present a thorough analysis of significant findings and the enhancement of process flowsheets over time that can be useful for both research endeavors and industrial process improvements. The review focuses on the following techniques: acid methods, alkali methods, carbonate roasting/autoclaving methods, sulfuric acid roasting/autoclaving methods, chlorinating methods, and mechanochemical activation. Recently, microwaves (MWs), as an energy source, have been employed to transform α-spodumene into β-spodumene. Considering its energy-efficient and short-duration aspects, the review discusses the interaction mechanism of MWs with solids, MW-assisted decrepitation, and Li extraction efficiencies. Finally, the merits and/or disadvantages, challenges, and prospects of the processes are summarized.

Performance analysis of refuse‐derived fuel gasification plant with carbon capture and storage for power, heating, and hydrogen production

AbstractAmong various waste‐to‐energy technologies, gasification is one of the most promising, because of high efficiency, feedstock flexibility, and carbon capture potential. This case study is focused on comprehensive analysis of integrated gasification combined cycle‐based plant with refuse‐derived fuel (RDF) as feedstock and carbon capture. As there are hardly any studies focused on simulation of waste gasification with carbon capture, most of which are lacking important process specifics, this study addresses existing research gap. Process flowsheets are developed in detail according to literature data for various process configurations and simulated in AspenPlus software, while obtained results on material and energy balance were used for estimation of plant efficiency and performance indicators. Waste generation data in Novi Sad, Serbia, were used for determination of RDF flowrate. Configurations include different syngas cleaning pathways, final products (power, heating, and hydrogen) and co‐gasification with coal. Cogeneration increases overall plant efficiency from 27%–36% (power production only) to 63%–76%. High net hydrogen efficiencies, around 58%, compensate lower power and thermal energy production in hydrogen‐based configurations. Overall, co‐gasification produces better results due to higher feedstock heating value. Obtained results will be used in further research for environmental and economic evaluation to provide multi‐level assessment of proposed processes.

Comparison of dynamic tests of the modified purex process flowsheet using 30 and 45% TBF in isoparafin

Results of centrifugal contactor rig trials of the flowsheet of the first solvent extraction cycle in protective glove boxes using simulated solutions of spent nuclear fuel and 30 and 45% TBP in isoparaffin as a solvent are compared. It was shown that an increase in the TBP concentration to 45% resulted in deterioration of the quality of the products obtained by the same flowsheets with 30% TBP in Isopar L as a solvent. Comparison of experimental and computer simulated profiles of component distribution across the stages of extraction units demonstrated satisfactory agreement in nitric acid and uranium concentrations. At the same time, it was found that simulation model of zirconium, technetium, and neptunium extraction requires improvement considering interaction of these elements with complexing agents.

Selective recovery of antimony from Sb-bearing copper concentrates by integration of alkaline sulphide leaching solutions and microwave-assisted heating: A new sustainable processing route

The technical feasibility of leaching antimony from an antimony-bearing copper sulphide concentrate, using alkaline sulphide solutions and microwave-assisted and non-assisted heating technology, is investigated at a laboratory scale. The leaching test examines the influence of selective leaching reagent (Na2S and NaOH) concentrations, solid/liquid ratio, and temperature. The results indicate that antimony dissolution is highly selective (e.g. only Sb and As are leached), depending on the concentrations of leaching reagents and the leaching temperature. The influence of temperature on the mineral's dissolution, in the range 25–140 °C, is analysed from a thermochemical point of view using equilibrium databases. Under the optimal conditions: leaching agent: 250 g/L Na2S, 60 g/L NaOH, 2 h, 140 °C, with microwave assisted, the leaching efficiency of Sb reached 95.7 %. The antimony content in the copper concentrate is successfully reduced from 1.1 wt% to <0.2 wt% Sb, making it suitable for copper concentrate metallurgical processing. The study demonstrates that increasing temperature and NaOH/Na2S concentrations collectively enhance leaching efficiency, with a statistical significance, reducing both leaching time and the required temperature, compared to non-microwave-assisted leaching. Furthermore, it is established that excess free hydrogen sulphide ions ensure the efficient dissolution of the main impurities associated with penalties, such as antimony and arsenic, with limited copper and iron dissolution from the copper concentrate, predominantly chalcopyrite. Finally, an integrated hydrometallurgical process flowsheet for antimony removal and recovery from a sulphide copper concentrate is proposed.

Comparative assessment of simulation-based and surrogate-based approaches to flowsheet optimization using dimensionality reduction

This work proposes a framework for simulation-based and surrogate-based reduced space Bayesian optimization of process flowsheets. The framework uses global sensitivity analysis for dimensionality reduction via the identification of critical process variables that contribute significantly to the variability of the objective function (e.g. productivity and operating costs). Both simulation- and surrogate-based algorithms are applied to a biopharmaceutical and a chemical process simulator for the production of plasmid DNA and dimethyl ether (DME), respectively. Their capabilities are assessed in terms of the trade-off between computational effectiveness and solution accuracy. Results indicate that simulation-based Bayesian optimization achieves better objective function values, while surrogate-based Bayesian optimization is more computationally effective.

Improvement of mining and processing flowsheets at vein-type gold deposits

Improvement of mining and processing flowsheets at vein-type gold deposits

Cesium extraction from an alkali-free solution using a 4-tert-butyl-2-(α-methylbenzyl) phenol–di-(2-ethylhexyl) phosphoric acid synergistic system: A conceptual process flowsheet for separating cesium salt from salt-lake brine

Cesium is an important strategic resource, and solvent extraction is the most frequently used technology for its extraction from various minerals and brines. However, this common method faces operational and cost problems owing to large alkali consumption. A synergistic extraction system consisting of 4-tert-butyl-2-(α-methylbenzyl) phenol (t-BAMBP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) was designed and used to extract Cs+ from an alkali-free solution. The effects of variables such as: (i) pH, (ii) concentration of t-BAMBP and D2EHPA, (iii) temperature, (iv) Cs+ concentration, and (v) coexisting cations, on the Cs+ extraction performance of the synergistic system were investigated. The most suitable organic phase composition was 1.0 mol/L t-BAMBP and 0.1 mol/L D2EHPA in kerosene, and the synergistic coefficient was up to 57 at 25 °C and an organic/aqueous phase volume ratio of 1/1. The extraction sequence of cations using the t-BAMBP–D2EHPA synergistic system followed the descending order Cs+ > Rb+ > Ca2+ > K+ > Li+ > Mg2+ > Na+. The chemical formula of the extracted species was determined as [CsA(HA)(ROH)2] using the slope method. The Cs+ extraction process is an exothermic reaction with an enthalpy (ΔHo) of −55.3 kJ mol−1, confirmed by the thermodynamic study. After three-stage countercurrent extraction, the extraction efficiency of Cs+ was 92.6%, demonstrating excellent selectivity from coexisting cations. The t-BAMBP–D2EHPA synergistic system showed outstanding economic and environmental advantages and a good application prospect to develop a conceptual process flowsheet for extraction with this system and stripping with HCl to separate cesium salt from salt-lake brine.

Recovery of lactose from acid whey by nanofiltration: An experimental study

The flowsheet of an overall process to recover valuable products from raw acid whey is proposed. It considers typical pretreatments, an ultrafiltration step to remove proteins, a decalcification step to remove calcium and magnesium by precipitation, and a nanofiltration/diafiltration step for demineralization and deacidification of lactose. The performance of each step is evaluated and the characteristics of the main streams are estimated. The feasibility of lactose recovery after the decalcification step by nanofiltration is demonstrated by using a spiral wound module. Membrane characterization was performed at pH 4 and 50 °C, with an artificial solution containing lactose, lactic acid and sodium chloride, prepared to mimic the clarified supernatant from the decalcification unit. The feasibility of the simultaneous concentration and deacidification of lactose is finally validated by processing a real solution. With the real solution, the maximum removal of lactic acid, close to 87%, is obtained by operating with a nanofiltration (NF) step (at a concentration factor of 3.5) followed by a NF step operated in diafiltration mode (DF) at constant volume (at a dilution factor of 1.8). A lactic acid/lactose ratio of 0.018 g/g is achieved, with an overall lactose purity and yield of 93.6% and 98.2%, respectively, when operating at low pressure values (up to 12–14 bar). A preliminary process simulation is finally performed to identify the premises for process optimization of the NF+DF configuration. The success of the integrated NF+DF process is contingent upon the correct balance between the choice of the membrane and the operating conditions, which ensure lactose rejections exceeding 98.5% and lactic acid rejections falling below 20–30%, while maintaining transmembrane fluxes between 8 and 15 dm3/(hm2).

A hydrometallurgical process flowsheet for recovering MoO3 from Molybdenite

In this study, a comprehensive hydrometallurgical processing of molybdenite (MoS2) concentrate was investigated. This investigation involved a novel approach combining mechanical activation, leaching, and polyelectrolyte extraction methods. The integrated method effectively addressed the challenge of low leaching rate of molybdenite, resulting in the successful production of high-purity molybdenum trioxide. Milled molybdenite samples were analyzed by different methods of X-ray diffraction, atomic force and electron microscopy, and BET. The increasing trend of the specific surface area during milling was determined by a model fitting which was useful for optimization of milling time. Several leaching reagents were studied to achieve high molybdenum dissolution. The most promising results were achieved through a two-hour process, yielding an impressive leaching efficiency of 80% and a resulting Mo concentration of 6700 mg/L. Molybdenum recovery was efficiently carried out through polyelectrolyte extraction, as confirmed by ICP and CHNS analyses, demonstrating selective precipitation of molybdenum from the solution. The subsequent calcination of the precipitated molybdenum(VI) compound resulted in the production of high-purity molybdenum trioxide. Furthermore, a conceptual hydrometallurgical treatment process for molybdenite concentrate was proposed, aiming to recover molybdenum, sulfuric acid, and copper. This proposed process presents a promising avenue for further exploration in pilot plant studies within the molybdenum industry.

Parallel Genetic Algorithm Interface II: A novel computational tool for accelerated simulation-based optimization

The ever increasing power of computational tools encouraged by the general need for development of more sustainable technologies fuels the interest in modern optimization approaches. While simulation-based optimization has been receiving considerable attention in the past decades, it still struggles to overcome some challenges, namely excessive computation time. This study proposes a novel optimization interface, the Parallel Genetic Algorithm Interface II (PAGAN-II), which utilizes parallelization of flowsheet simulations to drastically reduce the optimization time without the need to use clustered CPUs and/or modified optimization algorithms. Results of a detailed performance study showed up to 2100% increase in computation rate when optimizing demanding process flowsheets; and approximately 300% increase when optimizing simple ones. Capabilities of the proposed interface were demonstrated by optimization of a 5 MTPA C3MR LNG technology processing 12 different feedstocks, where a 15–30% decrease in the specific energy consumption was achieved. At the same time, the algorithm increased the optimization speed 13-fold compared to the traditional approach. This translates into a reduction of optimization time from 69 days of non-stop computation to approximately 7 days.

Separation of vanadium, tungsten, and arsenic from alkaline leachate of spent SCR catalysts via coextraction and stepwise stripping

The application of sodium hydroxide solution in the treatment of spent SCR catalysts has emerged as a prevalent technique for the recovery of titanium dioxide. Nonetheless, this method yields a substantial quantity of wastewater containing vanadium, tungsten, and arsenic, posing significant challenges for recycling, and resulting in the unnecessary disposal of valuable metals. In this study, the separation of vanadium, tungsten, and arsenic from alkaline leachate of spent SCR catalysts was investigated using modified Aliquat 336 with SO42− (MA336-S). Firstly, 98.88 % and 97.93 %, and 13.27 % of vanadium, tungsten, and arsenic were coextracted by MA336-S, and the electrospray ionization mass spectrometry and fourier transform infrared spectroscopy were employed to verify the formation of [(R3CH3N)2HVO4] and [(R3CH3N)2WO4]. Afterwards, the effective separation of vanadium, tungsten, and arsenic in organic phase was achieved by stepwise stripping. When Na2SO4 was used as the stripping agent, the stripping efficiency for arsenic reached 96.06 %. The selective stripping of vanadium and tungsten was achieved using 2.5 M NaOH and 1 M Na2SO4 + 1 M NaOH, respectively, resulting in stripping ratios of 99.59 % for vanadium and 99.15 % for tungsten. An extremely high separation factor of vanadium and tungsten (βV/W, 2388) can be achieved. Subsequently, the organic phase was preserved for recycling. A comprehensive process flowsheet was clarified for the efficient separation of vanadium, tungsten, and arsenic from the alkaline leachate of spent SCR catalysts, thereby facilitating a synergistic and enhanced recovery of these valuable metals from waste resources.

Evaluation of hydrometallurgical black mass recycling with simulation-based life cycle assessment

PurposeThe recycling of lithium-ion batteries is an emerging field faced with the challenge of recovering more than the most valuable elements from the batteries. While the literature presents many innovative approaches to the problem, an overview of the technical and environmental prospects of hydrometallurgical black mass recycling remains crucial. The goal was to analyze the impacts of a black mass process flowsheet and suggest ways to further reduce the impacts of battery recycling.MethodsThe flowsheet was drafted from the literature by combining both state-of-the-art and experimentally demonstrated unit processes by starting with the leaching system, where reductive leaching is performed using only the copper and iron impurities already present in the black mass. The process targeted copper, manganese, cobalt, nickel, and lithium recovery, and three scenarios for manganese recovery were investigated. The flowsheet was simulated using HSC Sim software, and the mass and energy balances were adapted into internally consistent life cycle inventories. The scope was “gate-to-gate” in Europe and CML methodology was used for impact assessment.Results and discussionAssuming that mechanical pre-treatment carries more environmental benefits than burdens, the results indicated that hydrometallurgical black mass recycling had a tentatively lower environmental footprint compared to virgin raw materials in all impact categories except ozone depletion, the results indicated that hydrometallurgical black mass recycling had a tentatively lower environmental footprint compared to virgin raw materials in all impact categories except ozone depletion. Sulfuric acid and neutralizing chemicals were among the most significant contributors to the impacts, and therefore further analysis was conducted based on an experimental study on low acid leaching with a low (< 0.5 M) initial sulfuric acid concentration instead of the baseline 2 M. This reduced the impacts by approximately 30–40% in all categories by decreasing downstream chemical consumption, and more significantly decreased ozone depletion. The challenges and opportunities for further process improvement were also considered.ConclusionsThe study highlights the importance of process optimization to improve the environmental sustainability of battery chemical production, but also revealed critical research gaps in the experimental literature. Rather than focusing on a single unit process, experimental black mass recycling research should aim at finding solutions that are optimal for the up- and downstream units, such as minimization of aluminum in the black mass and acid consumption.

Novel Separation Processes and Their Applications

Separation processes are an integral part of any process flow sheet. Various techniques can beused to separatethe mixture depending on the raw mix. Sometimes, two or more methods must be used to get the desiredproduct. Differences in chemical and physical properties also help decide the separation technique that mustbe used. An external agent, any form of energyor matter, can act as the driving force for the separation. Someof these techniques are conventional processes like distillation, filtration, adsorption, and absorption, whichhave already been well-studied and extensively used. These days newer separation processes called novelseparation processes, such as membrane separation, gas separation, supercritical fluid extraction, use ofultrasonics, chromatographic separation, magnetic projection, and liquid- liquid extraction, among manyothers, are gaining importance in the area of research and implementation. Novel processes were firstimplemented as analytical tools in laboratories. However, they developed rapidly to become significant commercially and technically. The development in gas separation techniques has led to using Liquified Natural Gas in Air Separation Units to produce high-purity nitrogen and oxygen4. Novel separation methods also include ultrasound to enhance separation processes like extraction, demulsification, and crystallisation. Pressure-driven processes are a subset of membrane separation techniques where pressure is utilised as a driving force for separation, with asemipermeable membrane acting as a barrier. This method has various applications ranging from wastewater treatment to dairy processing. Chiral chromatography is used for enantiomeric separations by the use ofHPLC. A new magnetic separation process proposes the separation of plastics by submerging them in a paramagnetic medium and attaching a magnet. This results in moving the particles inside the medium with different trajectories, thereby separating them. This article will scrutinise and briefly describe the essential aspects and developments of novelseparation processes and their applications.

Proposals for the Use of Thermoelectric Modules for Pasteurization and Cooling of Milk on the Farms

The process flow sheets of environmentally friendly thermoelectric pasteurizers-coolers of milk are proposed. The methodology for thermal calculation of the power of thermoelectric modules of the milk pasteurizer-cooler for the farms with robotic milking and the basic variants of using thermoelectric modules for the primary processing of livestock products are presented. It has been shown that thermoelectric modules are promising option for the farms with milking robots where low cooling capacity, the heat for the pasteurization and the possibility of reversed process are needed. Furthermore these modules can be effectively used in combination with natural cold and heat recovery.

Development of alternate process flowsheets to recover an unconventional resource rare earth bearing placer garnet and sillimanite from Southeast Coast of India

ABSTRACT In the present study unconventional resources bearing rare earth mineral garnet and sillimanite have been attempted to recover using different alternate flowsheets. The best commercial grade garnet and sillimanite products are obtained from total heavy mineral concentrate recovered by using a spiral concentrator. The garnet product obtained after cleaning with spiral followed by a magnetic separator has a garnet grade of 98.8%, with a recovery of 97.2% and 4.13% overall yield from the bulk sample containing 4.5% garnet. In case of sillimanite also the spiral material is cleaned with a magnetic separator and followed by flotation yields a sillimanite material containing 98.6% sillimanite grade, with a recovery of 95.3% and an overall yield of 3.9% from most feed sample contain 4.0% sillimanite. Therefore, it is recommended to use gravity to remove the gangue ore before it enters the concentrator and to use magnetic equipment for garnet and flotation to obtain commercial grade sillimanite. Rare earth elements can be recovered from this level of garnet and sillimanite.

Exploring the REEs Energy Footprint: Interlocking AI/ML with an Empirical Approach for Analysis of Energy Consumption in REEs Production

Rare earth elements (REEs including Sc, Y) are critical minerals for developing sustainable energy sources. The gradual transition adopted in developed and developing countries to meet energy targets has propelled the need for REEs in addition to critical metals (CMs). The rise in demand which has propelled REEs into the spotlight is driven by the crucial role these REEs play in technologies that aim to reduce our carbon footprint in the atmosphere. Regarding decarbonized technologies in the energy sector, REEs are widely applied for use in NdFeB permanent magnets, which are crucial parts of wind turbines and motors of electric vehicles. The underlying motive behind exploring the energy and carbon footprint caused by REEs production is to provide a more complete context and rationale for REEs usage that is more holistic. Incorporating artificial intelligence (AI)/machine learning (ML) models with empirical approaches aids in flowsheet validation, and thus, it presents a vivid holistic picture. The energy needed for REEs production is linked with the source of REEs. The availability of REEs varies widely across the globe. REEs are either produced from ores with associated gangue or impurities. In contrast, in other scenarios, REEs can be produced from the waste of other mineral deposits or discarded REEs-based products. These variations in the source of feed materials, and the associated grade and mineral associations, vary the process flowsheet for each type of production. Thus, the ability to figure out energy outcomes from various scenarios, and a knowledge of energy requirements for the production and commercialization of multiple opportunities, is needed. However, this type of information concerning REEs production is not readily available as a standardized value for a particular material, according to its source and processing method. The related approach for deciding the energy and carbon footprint for different processing approaches and sources relies on the following three sub-processes: mining, beneficiation, and refining. Some sources require incorporating all three, whereas others need two or one, depending on resource availability. The available resources in the literature tend to focus on the life cycle assessment of REEs, using various sources, and they focus little on the energy footprint. For example, a few researchers have focused on the cumulative energy needed for REE production without making assessments of viability. Thus, this article aims to discuss the energy needs for each process, rather than on a specific flowsheet, to define process viability more effectively regarding energy need, availability, and the related carbon footprint.

Sequential hydrotalcite precipitation, microbial sulfate reduction and in situ hydrogen sulfide removal for neutral mine drainage treatment

This study proposed and examined a new process flowsheet for treating neutral mine drainage (NMD) from an open-pit gold mine. The process consisted of three sequential stages: (1) in situ hydrotalcite (HT) precipitation; (2) low-cost carbon substrate driven microbial sulfate reduction; and (3) ferrosol reactive barrier for removing biogenic dissolved hydrogen sulfide (H2S). For concept validation, laboratory-scale columns were established and operated for a 140-days period with key process performance parameters regularly measured. At the end, solids recovered from various depths of the ferrosol column were analysed for elemental composition and mineral phases. Prokaryotic microbial communities in various process locations were characterised using 16S rRNA gene sequencing. Results showed that the Stage 1 HT-treatment substantially removed a range of elements (As, B, Ba, Ca, F, Zn, Si, and U) in the NMD, but not nitrate or sulfate. The Stage 2 sulfate reducing bioreactor (SRB) packed with 70 % (v/v) Eucalyptus woodchip, 1 % (w/v) ground (<1 mm) dried Typha biomass, and 10 % (w/v) NMD-pond sediment facilitated complete nitrate removal and stable sulfate removal of ca. 50 % (50 g-SO4 m−3 d−1), with an average H2S generation rate of 10 g-H2S m−3d−1. The H2S-removal performance of the Stage 3 ferrosol column was compared with a synthetic amorphous Fe-oxyhydroxide-amended sand control column. Although both columns facilitated excellent (95–100 %) H2S removal, the control column only enabled a further ca. 10 % sulfate reduction, giving an overall sulfate removal of 56 %. In contrast, the ferrosol enabled an extra 99.9 % sulfate reduction in the SRB effluent, leading to a near complete sulfate removal. Overall, the process successfully eliminated a range of metal/metalloid contaminants, nitrate, sulfate (2500 mg-SO4 L−1 in the NMD to <10 mg-SO4 L−1 in the final effluent) and H2S (>95 % removal). Further optimisation is required to minimise release of ferrous iron from the ferrosol barrier into the final effluent.