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Solvent extraction scheme to isolate Zn, Cu, and Ni from glutamate media as hypothetical product of electric arc furnace dust alkaline leaching was developed, with concentrations being 17.6, 0.35, and 0.14 g/L, respectively. Three extractants were investigated: Cyanex 272, DEHPA, and Acorga M5640 selectively separated Zn, Ni, and Cu from each other. Aside from pH, parameters investigated included O/A ratio, extractant concentration in kerosene as diluent, and sulfuric acid concentration as stripping agent. pH was the most critical factor in determining the separation factor among three metals since pH controlled metal speciation in pregnant leach solution and regulated the interaction between metal ions and extractant. Based on previous studies, a flowsheet for Zn, Cu, and Ni isolation is proposed, which obeys the following sequence: Zn separated from Cu and Ni by Cyanex 272 (in pregnant leach solution at pH 8, log separation factor Zn–Cu 4.78, Zn–Ni 2.51), followed by Ni separation from Cu by DEHPA (in raffinate at pH 7, log separation factor Ni–Cu 3.92), and finally Cu extraction (in raffinate at pH 4, log distribution coefficient 3.19). Sulfuric acid was proved to be a suitable stripping agent with optimum concentrations of Zn, Ni, and Cu being 0.5, 0.25, and 2 M, respectively.

Hoidas Lake lies in the Northern Rae Geological Province, in the general vicinity of many of Saskatchewan's large uranium mines. The mineralogy of the Hoidas Lake rare-earth deposit differs from most other such deposits in that it is hosted in equal abundance in veins containing apatite and allanite mineral groups. Hoidas Lake also differs from other deposits in that it contains a significant amount of heavy rare-earth elements, such as dysprosium. This abundance of heavy Rare Earth Elements (REE’s) is significant, as there is a growing demand for the heavier rare earths in high-tech manufacturing (such as the use of dysprosium in the manufacturing of hybrid car components). Recently, metallurgical testing was performed on a Hoidas Lake REE deposit composite. These investigations included characterization, flotation testing, heavy media separation, magnetic separation testing, whole ore leaching studies, bond work index grindability testing, and relative abrasion index testing. This paper summarizes this research effort.

Chemical and mineralogical characterization of Malaysian monazite, a phosphate mineral, bearing rare earth elements separated from the tin tailings originated from Ipoh, Perak, Malaysia, was performed in this paper. The study aims to collect detailed information on the chemical composition, crystal phases, and microstructure of the mineral monazite concentrate that would aid to optimize the subsequent hydrometallurgical processes for high-efficient separation of thorium and other associated rare earth elements. A systematic characterization study of the concentrate was conducted using techniques such as optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR). These techniques analyzed the morphological details on the surface, elemental analysis, and mineral association assessment and identified the surface functionalization groups. The bulk composition and the mineral phases in which the elements are present were studied by wavelength-dispersive X-ray fluorescence (WD-XRF) and X-ray diffraction (XRD) studies respectively. The XRF analysis confirmed the presence of Ce, La, Nd, Pr, and Y (rare earth oxides: REO’s ~ 60 wt.%) while thorium dioxide (ThO2) accounted for 7 wt.% of the total composition. Traces of Ca, K, Al, Fe, Ti, and Mn were also confirmed by SEM elemental mapping. The XRD results confirmed that the concentrate was primarily composed of monazite (Ce, La, Nd, Th (PO4)) along with minor impurity phases of quartz. Automated mineralogical analysis was used as a confirmatory tool to corroborate the preliminary evidences. Based on the particle size distribution analysis supported by SEM, the majority of monazite grains were found to be present in the size range of 170–210 μm. Strong bands of PO4 and SiO4 were observed in the IR spectra corresponding to the phospho-silicate matrix of the REE mineral.

The efficacy of monosodium glutamate (MSG) as a lixiviant for the selective and sustainable leaching of zinc and copper from electric arc furnace dust was tested. Batch leaching studies and XRD, XRF and SEM-EDS characterization confirmed the high leaching efficiency of zinc (reaching 99%) and copper (reaching 86%) leaving behind Fe, Al, Ca and Mg in the leaching residue. The separation factor (concentration ratio in pregnant leach solution) between zinc vs. other elements, and copper vs. other elements in the optimum condition could reach 11,700 and 250 times, respectively. The optimum conditions for the leaching scheme were pH 9, MSG concentration 1 M and pulp density 50 g/L. Kinetic studies (leaching time and temperature) revealed that the saturation value of leaching efficiency was attained within 2 h for zinc and 4 h for copper. Modeling of the kinetic experimental data indicated that the role of temperature on the leaching process was minor. The study also demonstrated the possibility of MSG recycling from pregnant leach solutions by precipitation as glutamic acid (&gt, 90% recovery).

The recovery of platinum group elements (PGE (platinum group element coating), Pd, Pt, and Rh) from used catalytic converters, using low energy and fewer chemicals, was developed using potassium bisulfate fusion pretreatment, and subsequently leached using hydrochloric acid. In the fusion pre-treatment, potassium bisulfate alone (without the addition of an oxidant) proved to be an effective and selective fusing agent. It altered PGE into a more soluble species and did not react with the cordierite support, based on X-Ray Diffraction (XRD) and metallographic characterization results. The fusion efficacy was due to the transformation of bisulfate into pyrosulfate, which is capable of oxidizing PGE. However, the introduction of potassium through the fusing agent proved to be detrimental, in general, since potassium formed insoluble potassium PGE chloro-complexes during leaching (decreasing the recovery) and required higher HCl concentration and a higher leaching temperature to restore the solubility. Optimization on the fusion and leaching parameter resulted in 106% &plusmn, 1.7%, 93.3% &plusmn, 0.6%, and 94.3% &plusmn, 3.9% recovery for Pd, Pt, and Rh, respectively. These results were achieved at fusion conditions: temperature 550 &deg, C, potassium bisulfate/raw material mass ratio 2.5, and fusion time within 30 min. The leaching conditions were: HCl concentration 5 M, temperature 80 &deg, C, and time within 20 min.

This paper demonstrates the recovery of valuable metals from shredded Waste Printed Circuit Boards (WPCBs) by bromine leaching. Effects of sodium bromide concentration, bromine concentration, leaching time and inorganic acids were investigated. The most critical factors are sodium concentration and bromine concentration. It was found that more than 95% of copper, silver, lead, gold and nickel could be dissolved simultaneously under the optimal conditions: 50 g/L solid/liquid ratio, 1.17 M NaBr, 0.77 M Br2, 2 M HCl, 400 RPM agitation speed and 23.5 &deg, C for 10 hours. The study shows that the dissolution of gold from waste printed circuit boards in a Br2-NaBr system is controlled by film diffusion and chemical reaction.

Tin-, iron-bearing tailing is a typically hazardous solid waste in China, which contains plenty of valuable tin, iron elements and is not utilized effectively. In this study, a multistage utilization process was put forward to get the utmost out of the valuable elements (tin and iron) from the tailings, and a gradient-recovery method with three procedures was demonstrated: (1) An activated roasting followed by magnetic separation process was conducted under CO-CO2 atmosphere, tin and iron were efficiently separated during magnetic separation process, and 90.8 wt% iron was enriched in magnetic materials while tin entered into non-magnetic materials; (2) The tin-enriched non-magnetic materials were briquetted with CaCl2 and anthracite and roasted, then tin-rich dusts were collected during the chloridizing roasting process; (3) The roasted briquettes were infiltrated in melting NaNO3 to prepare NaNO3/C-PCMs by a infiltration method. Three kinds of products were obtained from the tailings by the novel process: magnetic concentrates containing 64.53 wt.% TFe, tin-rich dusts containg 52.4 wt.% TSn and NaNO3/C-PCMs for high temperature heat storage. Such a comprehensive and clean utilization method for tin-, iron-bearing tailings produced no secondary hazardous solid wastes, and had great potential for practical application.

Electric vehicles (EVs) will be an important part of a low-carbon economy. Future EV adoption depends on overcoming multiple barriers, including charging infrastructure, sufficient electricity generation, and the availability of battery raw materials at acceptable costs, including cobalt, copper and nickel – which typically are co-produced. Various EV projections have been made, along with associated requirements for battery raw materials (demand). There have been separate assessments of the availability of raw materials (supply). However, integrated assessments of supply and demand and their interaction over time are lacking to support decision-making. Using a dynamic market model that reflects the co-produced nature of cobalt, copper and nickel production as well as recycling, we estimate global output of these three metals under different EV growth scenarios from 2020 to 2040. Results suggest that starting in 2025, replacement demand for battery raw materials becomes important. Thus, estimates for future material demand that consider only demands from new EVs are incomplete and misleading. EV deployment and associated increased demand for raw materials will have a greater impact on prices for cobalt than nickel and, in turn, for nickel than copper. High EV deployment scenarios will be difficult to achieve without larger supplies of copper, nickel and cobalt than forthcoming under the conditions modeled here, which anticipates a six-year time lag between a demand increase and the expansion of metal-production capacity. Shortening battery lifetimes and improving collection and recycling rates increase secondary supply, but the extent to which these factors support additional EV deployment is mixed.

Flash furnace electrostatic precipitator dust (FF-ESP dust) is a recycle stream in some primary copper production facilities. This dust contains high amounts of copper. In some cases, the FF-ESP dust contains elevated levels of bismuth and arsenic, both of which cause problems during the electrorefining stages of copper production. Because of this, methods for separation of copper from bismuth and arsenic in FF-ESP dust are necessary. Hydrometallurgical leaching using a number of lixiviants, including sulfuric acid, sulfurous acid, sodium hydroxide, and water, were explored. Pourbaix diagrams of copper, bismuth, and arsenic were used to determine sets of conditions which would thermodynamically separate copper from bismuth and arsenic. The data indicate that water provides the best overall separation between copper and both bismuth and arsenic. Sodium hydroxide provided a separation between copper and arsenic. Sulfurous acid provided a separation between copper and bismuth. Sulfuric acid did not provide any separations between copper and bismuth or copper and arsenic.

Globally, copper, silver, and gold orebody grades have been dropping, and the mineralogy surrounding them has become more diversified and complex. The cyanidation process for gold production has remained dominant for over 130 years because of its selectivity and feasibility in the mining industry. For this reason, the industry has been adjusting its methods for the extraction of gold, by utilizing more efficient processes and technologies. Often, gold may be found in conjunction with copper and silver in ores and concentrates. Hence, the application of cyanide to these types of ores can present some difficulty, as the diversity of minerals found within these ores can cause the application of cyanidation to become more complicated. This paper outlines the practices, processes, and reagents proposed for the effective treatment of these ores. The primary purpose of this review paper is to present the hydrometallurgical processes that currently exist in the mining industry for the treatment of silver, copper, and gold ores, as well as concentrate treatments. In addition, this paper aims to present the most important challenges that the industry currently faces, so that future processes that are both more efficient and feasible may be established.

Due to the demand for rare earth elements for everyday technology and applications, there has been much research initiation into the extraction and recovery of rare earth elements. An otherwise unknown mineral, eudialyte is a zircon silicate consisting of rare earth oxides, specifically the heavy REO yttrium (III), with only trace amounts of thorium and uranium. The first part of this project aimed at finding an efficient way to liberate and upgrade eudialyte to concentrate the REO content. A combination of gravity and magnetic separation techniques were employed, resulting in limited success. The second part looked at the hydrometallurgical processing of eudialyte through various leaching experiments with sulfuric acid. In all, this project will discuss why certain processes were utilized over others, as well as the difficulties that arose during processing.

Disclosed herein is a treated ore solid comprising a reduced amount of a contaminant, for example arsenic, compared to the ore solid prior to treatment. Also disclosed are temperature and pressure modifications, parameters, and methods for treating an ore solid by pressure oxidation leaching of enargite concentrates. The disclosed methods and processes may be applied to copper sulfide orebodies and concentrates containing arsenic. In some cases, the disclosed methods and systems extract, remove, or reduce contaminants, for example arsenic, from an ore containing solution at moderately increased temperature, pressure, and oxygen concentration, and in the presence of an acid.

A variety of processing technologies exist for recovery from both primary and secondary sources of rhenium. Currently, there are no known primary rhenium deposits; thus, the method in which primary rhenium is produced is dependent on the commodity of which it is a byproduct, e.g., copper, molybdenum, uranium, etc. In addition, focus on the recovery of rhenium from secondary sources, such as alloy scraps and catalysts, is continually growing. This paper presents a review of both primary and secondary processing technologies for the recovery of rhenium.

Globally, the primary production of antimony is now isolated to a few countries and is dominated by China. As such it is currently deemed a critical and strategic material for modern society. The metallurgical principles utilized in antimony production are wide ranging. This paper will outline the mineral processing, pyrometallurgical, hydrometallurgical and electrometallurgical concepts used in the industrial primary production of antimony. As well an overview of the occurrence, reserves, end uses, production, and quality will be provided.

Today, with a stringent economic and environmental climate prevailing in the copper business, there is increased interest in evaluating new processing alternatives for production. Hydrometallurgical pressure oxidation of copper concentrates is one of the more viable approaches, and several technological candidates have emerged. Of these, an overlooked but, ironically, the first industrially proven methodology utilized nitrogen species catalyzation in the oxidizing pressure-leach system to produce copper via solvent extraction/electrowinning. Given its advantages, this may prove to be a feasible process alternative for the future. In this article, the history of the system and its application to copper concentrates and ores will be outlined. In particular, a non-cyanide methodology for effective recovery of precious metals from chalcopyrite concentrates will be discussed.

The Gordonsville Operation of Pasminco US Inc. along with the Center for Advanced Mineral and Metallurgical Processing (CAMP) at Montana Tech studied, developed and implemented a pilot scale hydrometallurgical facility for the industrial recovery of germanium and gallium. This paper describes the joint testing and engineering program that culminated in this successful process.

Copper sulfides are generally treated by flotation followed by smelting. However, concerns over air pollution have made governments tighten their regulations regarding the emission of sulfur dioxide. Thus, hydrometallurgical techniques seem to be the most convenient methods to selectively extract non-ferrous metals. In this study, the leaching kinetics of copper from low-grade concentrate by nitrite salt was investigated. The probabilities of several chemical reactions and the products formed were explained based on literature data and thermodynamic analysis. The copper concentrate was obtained from a flotation plant in the Kastamonu region of Turkey. Leaching experiments were conducted in sulfuric acid electrolyte (0.5 M-2.0 M) containing nitrite compounds (0.025 M-0.15 M) at a moderate temperature (80-120 degrees C). A high level of copper recovery (96%) from low-grade chalcopyrite concentrate was obtained under a total pressure of 6 atm at 120 degrees C within 2 h when using small amounts of nitrite species due to their autocatalytic behavior in acidic solutions. Elemental sulfur was the primary leaching product on the mineral surface, as confirmed using XRD and SEM/EDX analysis, and the formation of the sulfur layer inhibited leaching rate at later stage of dissolution process. (c) 2013 Elsevier B.V. All rights reserved.

A new process for smelting copper, Looping Sulfide OxidationTM (LSOTM) significantly and positively alters the smelting energy balance. This process uses copper oxide in conjunction with air for the desulfurization of copper and chalcopyrite concentrates. Copper oxide is regenerated in a flash type furnace and then “looped” back for the oxidation of the copper concentrate. Heat and material balances show that the Looping Sulfide OxidationTM process requires significantly lower net energy than conventional technology. This process produces anode copper and higher SO2 content off-gases for efficient formation of sulfuric acid. Additionally, the process yields slags with lower copper solubility as compared to the conventional technology.

The need for copper and molybdenum continues to grow as does the need for clean efficient metallurgical technologies capable of treating mixed metal concentrates. Currently, the use of hydrometallurgical pressure oxidation for copper concentrate treatment is growing. Furthermore, with limited molybdenum roasting capacity, stringent industrial molyb-denum concentrate roaster feed specifications, poor rhenium recoveries, and the inherent environmental issues asso-ciated with pyrometallurgical treatments, hydrometallurgical options are also now being pursued for molybdenum concentrates. Moreover, given the inherent grade, recovery and cost inefficiencies in the differential flotation process normally employed for molybdenum concentrates produced as a by-product of copper mining, there is a growing need to directly treat combined bulk copper and molybdenum concentrates. This minimizes molybdenum concentrate roasting limitations, specifications and requirements, while allowing simplification of increased efficiency of and cost reductions in upstream mineral processing circuits now producing separate copper and molybdenum concentrates by differential flotation. It would also allow more direct and efficient recovery of rhenium. Finally, hydro metallurgical technology will also reduce the need for costly final molybdenum concentrate impurity treatment circuits, thereby allowing for lower grade mixed metal molybdenum concentrates to be treated directly for a greater metal value realization. In summary, industrial nitrogen species catalyzed (i.e. NSC) hydro metallurgical pressure oxidation has many advantages over conventional pressure oxidation systems and offers a tangible process route to treat mixed bulk concentrates.This paper illustrates the fundamental concepts, confirmatory testing, application, proposed design and associated cost estimates for the development and industrial implementation of this proven mode of hydro metallurgical processing as applied combined to copper molybdenum rhenium concentrates.

The use of nitric acid in metal sulfide oxidation is not new. Many derivations of the technology have been researched and piloted for applications such as copper, nickel and precious metals. Again, as noted in Table 1, and as specifically applied to copper concentrates and precious metals, only the nitrogen species catalyzed (NSC) acid pressure leach has ever been built and operated successfully on an industrial scale [1].

In many instances, by-products or wastes containing antimony are generated during metallurgical processes. Although these materials pose environmental, recycling, and marketing challenges worldwide, the use of antimony hydrometallurgical leaching principles and technologies may provide a remedy. This paper outlines techniques for treating antimony-containing wastes and offers examples of applications for those wastes and by-products.

The Army weapons systems of the future will require improvements in transportability, maneuverability, and durability. These improvements can be realized through changes in materials of construction. Titanium-based alloys exhibit the exceptionally favorable strength-to-weight ratio, low density, as well as, superior resistance to erosion and impingement attack. It also displays outstanding resistance to a broad range of acids, alkalis, industrial chemicals, natural waters, and marine atmospheres. The current high costs associated with titanium-based alloys remain the main obstacle for widespread use as a material of construction. Although relatively high costs originate in the extraction and refining for the titanium based metal, the highest expenditures can be found in the fabrication of components. Free form fabrication is a growing technology that can be applied to weapons systems manufacturing. This technology utilizes digital information derived from 3D CAD data or data from 3D digitizing systems. Specialized software converts the 3D data into layered 2D data. This layered data is used by a variety of processes that join liquid, powder, or sheet materials to form parts comprised of plastic, metal, ceramic, or composite parts, in a layer upon layer manner. CAMP/Montana Tech has acquired a ProMetal R2, a three-dimensional printing machine, from The Ex One Company of Irwin, Pennsylvania. Titanium-based component fabrication with a three-dimensional printing machine, using of metals powders, and the layer-by-layer methodology, will result in a near-net shape component. For titanium components, the parts will then be subjected to a low-temperature binder removal followed by a high-temperature vacuum furnace sintering and completed by a hot isostatically press furnace stage. The process holds promise to reduce the fabrication costs for titanium components. This method is a more economical titanium fabrication technique when compared to current casting methods.