New Directions in Mineral Processing, Extractive Metallurgy, Recycling and Waste Minimization: An EPD Symposium in Honor of Patrick R. Taylor: Electrometallurgy
Sponsored by: Society for Mining Metallurgy and Exploration, TMS Extraction and Processing Division, TMS: Pyrometallurgy Committee, TMS: Hydrometallurgy and Electrometallurgy Committee, TMS: Materials Characterization Committee, TMS: Energy Committee, TMS: Recycling and Environmental Technologies Committee
Program Organizers: Ramana Reddy, University of Alabama; Corby Anderson, Colorado School of Mines; Erik Spiller, Colorado School of Mines; Edgar Vidal, NobelClad; Camille Fleuriault, Eramet Norway; Alexandra Anderson, Gopher Resource; Mingming Zhang, Baowu Ouyeel Co. Ltd; Christina Meskers, SINTEF
Wednesday 2:00 PM
March 22, 2023
Room: 33C
Location: SDCC
Session Chair: Rajyashree Lenka, The University Of Alabama; Uday Pal, Boston University
2:00 PM Invited
Energy Storage and Recovery Employing Iron-Iron Oxide System as an Electrofuel: Uday Pal1; Hadassah Flagg1; Haoxuan Yan1; Achim Seidel2; Georg Poehle3; Christian Redlich3; 1Boston University; 2Airbus Defence and Space; 3Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM
Electrofuels produced using renewable energy are the desired energy carrier for a carbon-free society. Iron powder produced electrolytically from iron oxide is an Electrofuel having high-energy density. They can be combusted to their oxide to release the chemical energy at different scales comparable to fossil fuels but without the harmful emissions. In this work we investigate a novel method of electrolytically reducing the iron oxide back to iron employing solid oxygen-ion conducting membrane (SOM) cell with liquid silver as the reducing medium. Liquid silver with the iron oxide is contained in the SOM cell, and the soluble oxygen is pumped out of liquid silver with a system of electrodes to generate the required reducing conditions. Since iron and liquid silver have no mutual solubility, the reduced iron is easily separated employing magnetic means. Details regarding cell design, electrode choices, and product characterization will be presented along with cell performance.
2:30 PM Invited
Electrochemical Mining of Municipal Solid Waste Incinerator Ashes: Michael Wang1; Duhan Zhang1; Yet-Ming Chiang1; 1MIT
Disposal of society’s trash is an environmental concern towards which municipal solid waste incineration (MSWI) plays a mitigating role by reducing landfill volumes and generating electricity. However, the economics of MSWI are increasingly challenged by the decreasing cost of renewable electricity. Meanwhile, MSWI ash represents an untapped resource for valuable materials, with embodied value ranging from $100-400/tonne. Here, we propose an electrochemical process for mining MSWI ash which uses MSWI electricity to electrolytically produce acid and base reagents for metals extraction and recovery. We demonstrate a process sequence that uses electrowinning and hydroxide precipitation to recover elements including Cu, Pb, Zn, Fe, Al, Mg, and Ca, with a purified silica co-product. Recovery of >90% of the targeted elements, at purities >90% for most elements, is demonstrated. Techno-economic analyses show that the proposed process provides net economic returns exceeding that from the current model combining electricity sales and ash landfilling.
3:00 PM Invited
Rare Earth and Critical Base Metals Electrodeposition using Urea - Choline Chloride Ionic Liquids: Rajyashree Lenka1; Ramana Reddy1; 1The University of Alabama
The electrodeposition of critical base metals and rare earth metals using a eutectic mixture of urea and choline chloride (IL) was discussed. The maximum current efficiencies obtained for Co, Zn, Pb and Cu were 95%, 91.3%, 96.4 % and 97%. The deposition of alloys of zinc like Zn-Sn, Zn-Cu, Zn-Ni, Zn-Mn and alloys of nickel like Ni-Mn, and Fe-Co-Ni were reported. The co-deposition of rare earth elements like Co-Nd and Sm-Co alloy were also carried out, because of rare earth metals cannot be deposited alone in urea melt due to their high negative reduction potentials of the rare earth ions. The effect of Urea and choline chloride or EMIC or BMIC on the electrodeposition of critical base metals and rare earth elements was discussed. The critical parameters in the electrodeposition processes were identified, such as current density and efficiency in metals and alloys production
3:30 PM Break
3:50 PM Invited
Simultaneous Deposition of Nickel and Electrolytic Manganese Dioxide: Kali Sanjay1; Barsha Marandi1; Abdul Sheik1; Bhagat Tudu1; Sweta Mahapatra1; 1CSIR-Institute of Minerals and Materials Technology
In the aqueous electrowinning of metals such as copper, nickel, cobalt, etc., the respective ions are reduced at cathode in an electrochemical cell while the anodic reaction is water oxidation. Similarly, during electrodeposition of metal oxides such as Electrolytic Manganese Dioxide (EMD) that takes place at anode, water redox reaction takes place at cathode. In the present work, simultaneous electrodepositionof nickel at anode and EMD at the cathode using membrane cell was investigated. The process can lead to reduction in the energy consumption during simultaneous electrodeposition compared to the energy consumed during deposition of nickel and EMD in two independent cells. This also reduces number of cells and therefore reduces capital cost. The parameters such as type of membrane, bath temperature, current density have been varied and its effect on the cathodic and anodic current efficiency has been studied. The quality of deposits and the design issues are discussed.
4:20 PM
Solid Oxide Membrane-based Electrolytic Process for the Conversion of Lunar Regolith to Oxygen and Metal (ROXY): Achim Seidel1; Matthias Funke1; Georg Poehle2; Christian Redlich3; Uday Pal4; 1Airbus Defence and Space; 2Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM; 3Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM; 4Boston University
Future exploration missions to the Moon and beyond will be dependent on the use of lunar regolith to produce metals/alloys and oxygen, provided they can be produced very efficiently such that their mass exceeds the mass of any needed consumables or spares to sustain the process. Among the many methods that have been studied so far, molten salt electrolysis with solid oxide membranes appears to be most promising since it meets those basic criteria. A specific implementation of this method to lunar applications called ROXY (Regolith to Oxygen and Metals) has been developed and tested, and the design and operations of related demonstration and production facilities have been investigated. In this work we will show that the performance figures of such facilities in terms of mass and power consumption in relation to the mass of produced materials are very attractive and meets all the necessary criteria.
4:40 PM
Electrowinning Impurities Out of Flowing Molten Chloride Salt for Heat Transfer Fluid Applications: Liam Witteman1; Kerry Rippy2; Patrick Taylor1; Judith Vidal2; 1Colorado School of Mines; 2National Renewable Energy Laboratory
The concentrated solar power and nuclear industry have garnered great interest in employing molten chloride salts as a heat transfer fluid; specifically, a blend of Mg-K-Na chloride salt. However, salt exposure to moisture results in highly corrosive oxide/hydroxide impurities and requires the need for salt purification. Typical salt purification strategies focus on the initial salt melting stage only and do not translate to on-line purification in a flowing salt loop. However, a novel strategy of electrowinning oxide/hydroxide impurities using Mg anodes and W cathodes has been demonstrated successfully in the laboratory. Here, we present a novel electrowinning reactor designed to continuously remove corrosive impurities out of flowing molten chloride salt at 500 °C. We will highlight preliminary results from flowing molten salt tests and evaluate the reactor’s utility at industrially relevant scales.
5:00 PM
Electrochemical Splitting of Salt Bearing Effluents: Abdul Sheik1; Sujana Gude1; Barsha Marandi1; Kali Sanjay1; Chinmaya Sarangi1; S Sharmila1; 1CSIR-Institute of Minerals and Materials Technology
Most of the hydrometallurgical processes generate considerable amount of salt bearing effluents due to acid and alkali reactions in various unit operations. These effluents though may not be toxic, owing to presence of high concentrations of salt, cannot be recycled into the process. These salts can be split back to produce acid and alkali for recycling in the process. The salt bearing effluents through electrochemical splitting to produce alkali and acid for recycling has been investigated with industrial effluents. In the present work, sodium sulphate and ammonium sulphate bearing effluents were electrochemically split to recover sodium hydroxide and ammonium hydroxide respectively while dilute sulphuric acid was recovered. Several ion-exchange membranes have been tested for their performance. The effect of variation in the operating conditions such as concentration of catholyte, feed and anolyte; current density, etc on the current efficiency and energy consumption have been studied.