Carbothermal Reduction Process Research Articles

Optimization of sintering process to fabricate high-density ultrafine-grained (HfNbTaTiZrW)C ceramic: A comparative study

The fabrication of senary carbide (HfNbTaTiZrW)C was achieved by carbothermal reduction process combined with three different kinds of sintering paths, including conventional single-step sintering (CS) and two kinds of two-step sintering (TSS-1 and TSS-2). It is revealed that the synthesized nanosized powders (∼102 nm) through carbothermal reduction exhibited excellent sintering capability to obtain a high density single-phase solid solution with homogeneous metal cation distributions at macro- and sub-micrometer scales, while atomic-level heterogeneity existed with Zr segregation. Compared to CS samples with bimodal microstructure, the application of two-step sintering significantly reduced the amounts of intergranular pores and (ZrHf)O2, accompanied with grain refinement. In particular, a well-designed TSS-2 route comprising short-term high-temperature followed by low-temperature sintering achieved ultrafine-grained bulk with grain size of 1.44±0.22 μm and excellent mechanical properties of elastic modulus of 480 MPa, microhardness of 23.4 GPa, and fracture toughness of 3.8 MPa·m1/2.

Utilizing pulverized waste polyvinyl chloride film as an alternative reducing agent for iron ore reduction

The research into using waste plastics as a substitute for coal powder and coke as a reducing agent has garnered significant attention, driven by various factors such as increased environmental concerns and growing interest in sustainable materials. This study investigates the process of carbothermal reduction using a mixture of waste polyvinyl chloride (PVC) and iron concentrate. Thermogravimetric analysis demonstrated that the heat-treated polyvinyl chloride products (PVC370) exhibited superior reaction properties compared to anthracite. Reduction tests indicated that PVC370-bearing pellets were less sensitive to temperature changes than anthracite-bearing pellets, highlighting a potential advantage of PVC370 in industrial applications. Moreover, the metallization ratio of PVC370-bearing pellets exceeded that of anthracite-bearing pellets before reaching 1150 °C. At a temperature of 1100 °C and a C/O of 0.8, the metallization ratio of PVC370-bearing pellets peaked at 83.17 %. During the reduction process of PVC370-bearing pellets, hydrogen (H2), carbon monoxide (CO), and hydrogen chloride (HCl) were efficiently released at relatively low temperatures. The efficiency of gas release in the reduction process could be attributed to certain factors, such as the composition or structure of the PVC370-bearing pellets. Notably, the quality of gasses generated during the reduction process of PVC370-bearing pellets is superior to that of anthracite-bearing pellets, even when considering chlorine content.

Planetary Soil Simulant Characterisation: NU-LHT-2M Study Case to Support Oxygen Extraction Lab Tests with a Low-Temperature Carbothermal Process

Since the landing on the lunar surface, the lunar regolith has begun to interact in different ways with landed elements, such as the wheels of a rover, astronaut suits, drills, and plants for extracting oxygen or manufacturing objects. Therefore, a strong effort has been required on Earth to fully characterise these kinds of interactions and regolith utilisation methods. This operation can only be performed by using regolith simulants, soils that are reproduced with the Earth’s rocks and minerals to match the real features. This article presents the main guidelines and tests for obtaining the properties of a generic simulant in terms of composition, physical and mechanical properties, solid–fluid interaction, and thermal properties. These parameters are needed for the designing and testing of payloads under development for planned lunar surface missions. The same tests can be performed on lunar, martian, or asteroid simulants/soils, both in laboratory and in situ. A case study is presented on the lunar simulant NU-LHT-2M, representative of the lunar highlands. The tests are performed in the context of an in situ resource utilisation (ISRU) process that aims to extract oxygen from the lunar regolith using a low-temperature carbothermal reduction process, highlighting the main regolith-related criticalities for an in situ demonstrator plant.

Kinetics of microwave carbothermal reduction of Sb2O3: Isothermal and non‐isothermal microwave thermogravimetric analysis

AbstractKinetics of antimony production via carbothermal reduction of Sb2O3–carbon powder–NaCl mixture using microwave and conventional heating was investigated to identify the dominant controlling mechanism. Results of conventional heating revealed the temperature range of conventional carbothermal reduction reaction is 500°C to 800°C, with the average activation energy of each stage being 81.97 kJ/mol (α = 0.1–0.5), 65.17 kJ/mol (α = 0.5–0.75), and 69.86 kJ/mol (α = 0.75–1.0), respectively. In the microwave field, the carbothermal reduction reaction of raw materials can be completed at 600°C to obtain antimony, and the weight loss data of the carbothermal reduction process were recorded for the first time. The above results show that the microwave field enhanced the interfacial chemical effect, accelerated the interfacial diffusion from the metal phase to the oxide phase, and reduced the activation energy of the carbon thermal reduction process to 6.85 kJ/mol. The growth index of antimony grain growth process is estimated to be 4.33, controlled by the surface diffusion. These data provide a reliable theoretical basis for studying the reduction reactions of minerals in microwave fields.

Coproduction of silicon nitride & oxynitride whiskers and precipitated silica from industrial rice husk ash

Rice industrialization generates large amounts of rice husk, and when this husk is burned, substantial volumes of ash are produced as a result. The lack of a sustainable application for these ashes constitutes a serious environmental liability. Employing rice husk ash as a starting material to manufacture higher-value products fulfills both environmental and economical purposes. Particularly, the presence of silica and carbon in intimate contact makes rice husk ash an attractive precursor for carbothermal reduction and nitridation processes. In the present work, a pre-treatment was applied to a locally sourced industrial rice husk ash, aiming to render not only a more appropriate starting material for carbothermal reduction and nitridation, but also precipitated silica as a by-product. This process involved a simple alkaline digestion step followed by filtering and acid precipitation of the solubilized silica. For carbothermal reduction and nitridation, the treated ash was introduced in graphite crucibles with graphite lids and held at soaking temperatures between 1200 °C and 1400 °C under a nitrogen atmosphere for 3 h. The pretreatment imposed on the ash permitted the adjustment of the carbon-to-silica ratio, producing a substantial improvement in the carbothermal reduction and nitridation results, and enabling the simultaneous obtention of precipitated silica. α- and β- silicon nitride, and silicon oxynitride whiskers were obtained through carbothermal reduction and nitridation of the treated rice husk ash. The whiskers obtained had lengths in the millimeter range with cross-sections ranging from about 100 nm up to 500 nm.

Mechano-thermic reduction of low-grade titanium ore for high-grade TiO2 synthesis

A systematic study on the mechano-thermic reduction of low-grade ilmenite concentrate for the production of high-grade TiO2 powder used in the production of non-oxide ceramics for cutting tool applications has been successfully carried out. Samples were prepared via planetary ball milling and carbothermic reduction processes, and the as-reduced product was subsequently leached in order to improve the synthesized TiO2 by removing the metallic iron in it and other minor soluble impurities dissolved in the iron. The mechano-thermic reduction was achieved by milling a representative mixture of ilmenite and carbon in a molar ratio of 1:1, followed by carbothermic reduction at 1000 °C in a laboratory high-temperature furnace for 60 min. The as-reduced product was subsequently leached at 80 °C for 6 h in a hydrochloric acid solution. It was found that there was a complete reduction of ilmenite to metallic iron and TiO2 at 1000 °C. The results of the FESEM showed there were only two distinct regions of metallic iron (bright region) and titanium dioxide (grey region) with minor traces of unreacted carbon (dark spots), although there was clear regional demarcation between these regions. However, the iron dissolution during the acid treatment was almost 100% as there were no peaks of iron in the as-leached powder. The results of these analyses confirmed the synthesis of high-grade TiO2, which finds application in cutting tool applications and other areas such as in reflective pigment production.

Research of Bayan Obo tailings characteristics and recovery methods

This paper presents a new method for the recovery of iron and rare earth elements (REEs) from Bayan Obo tailings, which are the waste materials from the extraction of iron and REEs from the Bayan Obo ore deposit in Inner Mongolia, China. The method is based on the combination of microwave-assisted carbothermal reduction and acid leaching. The microwave-assisted carbothermal reduction can effectively reduce the iron oxides and REE oxides in the tailings to metallic iron and REE metals, respectively, and separate them from the gangue minerals. The acid leaching can then dissolve the REE metals from the reduced product and obtain a high-purity REE solution. The effects of various parameters on the performance of the method were investigated and optimized, and the mechanisms and kinetics of the reactions were analyzed and modeled. The results showed that the method can achieve a high recovery rate of iron and REEs, a high selectivity of REEs, a low energy consumption, and a simple process. The economic and environmental benefits of the method are also significant, as it can utilize the Bayan Obo tailings and recover the valuable elements from them, and reduce the waste generation and greenhouse gas emission. The method provides a new and efficient technology for the utilization of Bayan Obo tailings and the recovery of iron and REEs, and contributes to the fundamental understanding of the microwave-assisted carbothermal reduction and acid leaching processes.

Non-isothermal kinetics and thermodynamics analysis of vanadium-titanium magnetite

Thermodynamic calculations and thermal analysis tests were performed to investigate the thermodynamic and kinetic behaviors of the carbothermal reduction of vanadium-titanium magnetite w(C)/w(O) and basicity on the carbothermal reduction process of vanadium-titanium magnetite based on the HIsmelt process. Thermodynamic analysis showed that the addition of basicity promoted the reduction of vanadium-titanium magnetite, and the reaction onset temperature gradually increased with the decrease of the valence states of the elements V, Ti and Fe in the product. Increasing the amount of carbon assigned to the system gradually increased the mass fractions of metal Fe and Fe3C and raised the mass fractions of Ti, V and their low valence compounds at equilibrium. Increasing the basicity had less effect on the Fe, V and Ti fractions of the equilibrium system. The results of kinetic tests showed that the maximum reduction degree and maximum reaction rate of the reduction reaction by increasing w(C)/w(O) and basicity increased, the apparent activation energy and the finger front factor decreased, and the reaction mechanism function of the non-isothermal kinetic reduction process was f(α) = (3/2)(1−α)4/3[(1−α)−1/3−1] −1 belonging to the three-dimensional Z-L-T diffusion model.

Cleaner extraction of white phosphorus from phosphate rock through molten salt electrolysis

White phosphorus (P4) is an essential raw material for the production of phosphorus chemicals. The conventional carbothermal reduction process used to extract P4 from phosphate rock is known as energy intensive and environmentally polluting, posing obstacles to meeting the urgent global demands for clean production and carbon neutrality. Moreover, the low product purity restricts its application in high-value industries. This paper presents an original approach that is both simple and coke-free for extracting high-purity P4. The method involves electrolyzing dissolved phosphate rock in molten CaCl2 at a mild temperature. We undertake an in-depth investigation into the dissolution behavior of phosphate rock in molten CaCl2 and the electrolysis behavior of the melt. The experiments demonstrate the rapid dissolution of phosphate in the rock when exposed to molten CaCl2, reaching saturation within a short time (e.g., within 10 min at 850 °C). The dissolution of phosphate shows a preference over silicates present in the phosphate rock. The electrochemical reduction of PO43− in molten CaCl2 is electrochemically reversible, as observed at potential scan rates not exceeding 0.20 V s−1. The obtained P4 product through electrolysis is of higher purity compared to the industrial-grade commercial product produced via carbothermal reduction. The implementation of pre-electrolysis can further improve the purity of the product and the current efficiency of the electrolysis process. The theoretical electricity and carbon consumption in the electrolysis method are estimated to be 9.12 kWh and 0.53 kg, respectively, for every 1 kg of P4 produced. These values are lower than the conventional carbothermal reduction process. This cutting-edge electrolysis method represents a paradigm shift towards a more sustainable development of the phosphorus chemical industry, thereby showcasing its potential for revolutionizing the field.

Phase Reduction and Thermodynamic Analysis of Ilmenite Ore by Carbothermal-Iodination using Different Carbon Reductants

The present study is on the combination of carbothermal reduction and iodination reaction (carboiodination) process for the phase reduction of ilmenite ore (FeTiO3). The aim is to understand the phase reduction and thermodynamic reaction analysis of ilmenite ore by a combined method of carbothermal-iodination using different carbon reductants (graphite and palm char). Graphite was used as a standard carbon reductant while palm char as a renewable carbon reductant was prepared via the pyrolysis technique. Ilmenite was mixed with carbon reductants and then first reduced by using a carbothermal reduction process at 1550℃. Then, the reduced samples were further investigated with iodination reaction in different temperature ranges of 900-1000 °C using a vertical tube furnace with mixed argon and iodine gas (0.2 L/min). The proximate and ultimate analyses of carbon reductants were analysed by CHON analyser and their microstructure by using SEM, while XRF and XRD were used for analyzing the chemical compositions and the phase reductions of raw ilmenite ore and reduced samples, respectively. The thermodynamics of possible reactions during carbothermal-iodination reactions were calculated by HSC Chemistry 6.0 software. By comparing graphite and palm char, palm char had an amorphous structure, with porous and high carbon content showing high potential for usage as a reductant in titanium extraction from ilmenite ore. The phases of ilmenite ore were ilmenite, rutile, and anatase transformed into rutile, pseudobrookite, and titanium oxide detected by XRD. Further reduction was performed by palm char where more rutile (TiO2) and titanium oxide (Ti3O5) developed from the iodination reaction at the highest temperature compared to graphite due to better properties and amorphous structure. The rutile and titanium oxide were found as stable phases from the thermodynamic analysis and confirmed with XRD. From the findings, the combination of carbothermal-iodination of ilmenite ore was possible and promising for rutile (TiO2) production in mineral extractions.

Investigation on Phase Evaluation of Ilmenite Ore by Carbothermal Reduction and Carboiodination Reaction

This article presented the thermochemical calculation and experimental investigation on the phase evaluation of ilmenite ore (FeTiO3) via carbothermal reduction and carboiodination reaction for titanium production using graphite as a reducing agent. The carbothermal reduction and carboiodination reactions were performed in two different furnaces. The carbothermal reduction was evaluated at a temperature of 1550°C with inert argon gas utilizing a horizontal tube furnace. The carboiodination reactions were evaluated in temperatures ranging from 900°C, 950°C, and 1000°C using a vertical tube furnace with mixed iodine gas with argon gas. XRF and XRD were used for analyzing the chemical compositions and the phase evolutions of raw ilmenite ore and the reduced samples, respectively. The findings showed that the Perak ilmenite ore predominantly has a greater concentration of TiO2 (71.27wt%), Fe2O3 (18.85wt%), and some other oxides like aluminum oxide and quartz. In addition, XRD revealed that the ilmenite phase was converted into rutile (TiO2) titanium oxide (Ti3O5, Ti2O3), titanium carbide (TiC), and iron (Fe) phases, after the carbothermal reduction process. However, after the carboiodination reaction, the ilmenite and rutile phases remained at temperatures 900°C, 950°C, and 1000°C. The HSC Chemistry software was used in the determination of the thermochemical calculation and the possible reactions during the reaction which play an important role in shortening the reduction process. The results revealed the carboiodination process is a promising process that can reduce energy consumption and shorten the titanium production processes, and it needs more studies.

Selective etching induced Fe3O4 cubes with orderly aligned porous structure for the effective lithium-ion storage and bisphenol A degradation

A novel nitrogen-doped carbon coated Fe3O4 cubes (Fe3O4@N-C) with orderly aligned porous (OA-P) structure was prepared by an acid etching and a carbothermic reduction process. This unique Fe3O4@N-C cubes demonstrated excellent performances in both lithium-ion batteries (LIBs) and bisphenol A (BPA) degradation with PMS activation. As an excellent anode for LIBs, the Fe3O4@N-C with unique OA-P structure could effectively accelerate the Li+ and electron transfer, relieve the volume expansion during Li+ insertion/desertion and enhance the electrical conductivity, which attributed to the reversible capacity of 985.6 mAh g-1 after 200 cycles at the current density of 100 mA g−1. As employed in the PMS activated BPA degradation, the Fe3O4@N-C achieved a degradation rate of 99.8% within 60 min with good stability, which is contributed to the synergistic effects of the increased adsorption and activation sites for PMS and the facilitated mass transport due to the OA-P structures. In addition, the activate-species quench tests and electron paramagnetic resonance measurements revealed that the 1O2-based non-radical path played a dominant role in the BPA degradation.

Thermodynamic behavior and kinetic analysis of carbothermal reduction process of low-grade oxysulfur lead–zinc ore

During the exploitation of sphalerite resources, a considerable amount of low-grade oxysulfur Pb–Zn deposits is generated, which poses a significant threat to the environment and soil and water conservation in mining areas. Therefore, low-grade Pb–Zn resources urgently require source emission reduction and appropriate utilization. This study applied a mineral technology and conducted X-ray diffraction and scanning electron microscopy–energy dispersive X-ray spectroscopy to investigate the phase transformation and the mechanism underlying the volatilization of Pb and Zn at different times and temperatures. The Pb–Zn volatilization kinetics of a low-grade oxysulfur Pb–Zn ore by a one-step pyrometallurgical process in an argon atmosphere was studied, and the effects of different temperature conditions on the Zn volatilization process were investigated. The results showed that the Zn-containing phase in the raw material was decomposed to ZnO and ZnS upon heating. Moreover, ZnO was reduced via carbothermal reduction, whereas ZnS was reduced via a CaO-assisted carbothermal reaction and volatilized in the form of gaseous Zn. In the Pb-containing phase, PbSO4 generated PbO, Pb, and PbS in the presence of Fe, FeS, and CaO. PbO was volatilized in the form of gaseous Pb through carbothermal reduction and interactions between PbS and PbO. The Pb–Zn volatilization reaction conformed to the shrinking core model with a constant size, and the volatilization-based removal of Pb and Zn process was controlled by internal diffusion. A macroscopic kinetic model of the reaction was established on the basis of experimental data. The apparent activation energy of Pb and Zn volatilization was 163.90 and 328.19 kJ/mol, respectively. This study promotes the utilization of the low-grade oxysulfur Pb–Zn ore through a pyrometallurgical method to provide theoretical support for large-scale industrial treatments.

Systematic thermodynamic and experimental studies for recovering indium and tin from indium tin oxide waste target with hydrogen

Resource utilization of waste indium tin oxide (ITO) can not only avoid the hazards of electronic waste, but also realize the recycling of dispersed metal indium (In). However, the current carbon thermal reduction process has the problems of high energy consumption and large carbon emissions. In this study, the feasibility and specific advantages of hydrogen reduction of waste ITO were explored by using high energy density and non-polluting H2 as reducing agent. The reduction process was thermodynamically analyzed by isothermal equation and molecular interaction volume model (MIVM), and the thermodynamic analysis results were verified by systematic experimental study. Experimental results showed that the reduction ratio of waste ITO can reach 99.43% under optimal conditions of 1173 K, 120 min, and 0.3 mol/L H2 flow rate, which indicated that the reduction process is feasible and efficient. Compared with vacuum carbothermal reduction process, hydrogen reduction process can reduce carbon emissions from the source, and theoretical energy consumption can be reduced by 70.12%. This work proposes a new method for recycling waste ITO that can reduce energy consumption and carbon emissions, providing further opportunities for the recycling of indium resources and the green economy of the electronics industry.

Microstructure Evolution and Phase Transformation of Iron Produced from the Sustainable Carbothermic Reduction Process of High-Pressure Acid Leaching Residue.

This paper describes the microstructure evolution and phase transformation of residue from the lateritic nickel ore high-pressure acid leaching (HPAL) during carbothermic reduction using palm kernel shell (PKS) charcoal as a reductant. The study consisted of thermodynamic calculations combined with analysis of reduction experiments. The thermodynamic assessment predicted that the main phases formed during the reduction process were γ-Fe metal, liquid metal, slag, and spinel, with abundance of reducing gas (CO and H2) at the temperature range of 750-1500 °C. The experimental study shows that the resulting product upon cooling was sponge iron or direct reduced iron when HPAL residue-PKS charcoal composites were reacted up to 1400 °C for 45 min. The sponge iron had an average apparent density of 5.8 ± 0.1 g/cm3 and a 90.8 ± 0.4% metallization degree. The microstructure analysis revealed that as the reduction time was increased, small iron nuggets began forming on the surface of the reduced product. By addition of Na2CO3, the separation of iron nuggets from slag appeared to be improved, hence enhancing the overall reduction process. Furthermore, iron nuggets' highest apparent density and metallization degree were obtained at 7 ± 0.1 g/cm3 and 98 ± 0.5%, respectively, when adding Na2CO3 of 6 wt %. The phase and microstructure analyses also revealed that the iron nuggets comprised coarse pearlite, eutectic cementite, ledeburite, and sulfides. Thus, this study offers alternative sustainable process conditions for simultaneously handling the HPAL residue using PKS waste to produce metallic iron.

Recovery of iron and alumina from iron–aluminum symbiotic ore via low–calcium carbothermal reduction

The iron-aluminum symbiotic ore, as an important strategic resource, has not been utilized due to the complex relationship between iron-aluminum minerals. In this work, a low-calcium carbothermal reduction method was proposed to treat the iron-aluminum symbiotic ore, and its performance and reaction mechanism were studied based on the Fe2O3-Al2O3-SiO2-CaO-Na2O system using XRF (X-ray fluorescence), XRD (X-ray diffractometer), SEM-EDS (scanning electron microscopy and energy dispersive spectrometer), VSM (vibrating sample magnetometer) and XPS (X-ray photoelectron spectroscopy), while the practical application on the iron–aluminum symbiotic ore was verified. The silicon is in the form of sodium calcium silicate compound during the low–calcium carbothermal reduction process, and the formation sequence of this compounds is Na2Ca3Si2O8 → Na2Ca2Si2O7 → Na2CaSiO4 with the increase of Na2CO3 amount. The iron- and aluminum-bearing phases in the reduction product are Fe, NaAlO2 and a small amount of ferrous and ferric compounds, NaAl11O17 and NaAlSiO4. Fe can be aggregated in the iron concentrate via magnetic separation and NaAlO2 can be recovered by leaching process. The main minerals in the reduction product from the iron-aluminum symbiotic ore obtained by the low-calcium reduction process are Fe, NaAlO2, Na2CaSiO4 and NaAlSiO4, and the iron metallization efficiency, the leaching efficiency of Al2O3 and the content of iron in the concentrate are 84.24%, 86.07% and 75.70% respectively under the optimal reduction conditions.

A novel approach for recovering multiple valuable metals from gallium-rich residues of phosphorus flue dust by two-stage vacuum reduction

In this study, the gallium-rich residue (GRR) obtained from phosphorus flue dust (PFD) after phosphorus removal was taken as the research object, and a novel technology for efficient recovery of valuable metals from GRR was proposed. This technology mainly adopted a two-stage vacuum carbothermal reduction process to selectively recover Zn and Pb and concentrate Ga. The feasibility of separating these three metals from GRR was investigated by thermodynamic analysis, and the effects of temperature, reducing agent dosage and holding time on metals recovery were explored. A promising recovery rate of up to 96.84%, 97.98% and 86.32% was achieved for Zn, Pb and Ga, respectively, under the optimal conditions. The purity of Zn and Pb in the condensate reached 98.57% and 80.56%, respectively, which can be used as raw materials for downstream enterprises and have high economic value. Additionally, the resulting Ga-rich condensate contained 1.49 % Ga, which is much higher than other traditional Ga-containing secondary resources, and can be further purified by hydrometallurgical process or other technologies. The whole process has almost no secondary pollution, with remarkable efficiency, providing a new approach for the comprehensive utilization of PFD.

Comparative study on the microstructure evolution and crystallization behavior of precursor-derived and mechanical alloying derived SiBCN

In this study, the chemical reactions and structural change during the transformation of the precursor into PDCs-SiBCN ceramic were investigated. Besides, the crystallization behaviors of precursor-derived (PDCs-SiBCN) and mechanical alloying derived (MA-SiBCN) SiBCN ceramics at different temperatures (1200–1700 ℃) were compared. Due to different amorphous structures derived from pyrolysis and amorphization processes, the silicon atoms units bonded by sp3 hybridization in PDCs-SiBCN and MA-SiBCN ceramics are SiC4 and SiC(4-x)Nx tetrahedral structure, respectively. Due to the phase separation of SiC(4-x)Nx tetrahedral structure at higher temperatures (>1400 ℃), PDCs-SiBCN ceramic has a higher resistance to crystallization but will suffer obvious carbothermal reduction process of Si3N4 during crystallization. Finally, the crystallization kinetics of SiC in MA-SiBCN ceramic were investigated. The temperature dependence of SiC crystallization in MA-SiBCN ceramic obeys the Arrhenius-type law with different activation energies in the low and high temperature ranges respectively due to the transition of the rate-controlling mechanisms.

Thermodynamic and experimental analysis of lithium selectively recovery from spent lithium-ion batteries by in-situ carbothermal reduction

The proliferation of spent lithium-ion batteries (LIBs) is a growing concern in the expanding electric vehicles (EVs) market. Recycling spent ternary LIBs significantly relieves environmental pressure and reduces resource waste. In this study, a reduction roasting-leaching process utilizing graphite was present to selectively recover lithium from spent ternary LIBs cathode. In detail, the selective leaching behavior of lithium elements under different roasting parameters was investigated. And a thorough analysis of the carbothermal reduction (CTR) process was then conducted to evaluate the process thermodynamically. The experimental results show that the roasted products of the cathode material are Li2CO3, MnO, NiO, CoO, Ni, and Co with process parameters of 10 wt% graphite content, 700 ℃, and 90 min roasting. 84.11 % of lithium elements are preferentially leached through the water-leaching process after CTR roasting. The technology not only promotes the recycling of waste resources but also provides a viable solution for the sustainable development of the LIBs industry.

Preparation and Electrochemical Dissolution of a Soluble Uranium Oxycarbide Anode.

A soluble uranium oxycarbide (UC0.4O0.6) anode was synthesized by a carbothermal reduction process, using U3O8, UO2, and graphite as raw materials, in a vacuum environment of 0.1 MPa at 1750 °C. The sintered UC0.4O0.6 exhibited excellent conductivity and stability in LiCl-KCl molten salt. The dissolution process of UC0.4O0.6 in molten salt was analyzed by linear sweep voltammetry (LSV), and the initial dissolution potential, rapid dissolution potential, and passivation potential were determined. The oxidation/reduction process of dissolved uranium ions in LiCl-KCl molten salt was studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). The experimental results showed that the addition of Li2O significantly reduced the volatilization of U(VI) and increased the concentration of UO22+ in molten salt. Finally, the product was conducted by electrolysis at 1.0 V and was confirmed to be UO2 by XRD and SEM-EDS analysis.