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By Wojciech Kasprzak, Guoxian Liang, Michel Gauthier, Mickael Dolle, Yulong Liu, Xueliang Sun, Hernando Villazon Amaris, Majid Talebi-Esfandarani, Pierre Sauriol, Thomas Bibienne, Gregory S. Patience, Delin Li, Steeve Rousselot

In the 1990s, LiFePO4 (LFP) was discovered as a cathode material for lithium ion batteries and was successfully used in the variety of devices such as power tools, E-bikes and grid accumulators. New challenges associated with use of lithium ion batteries for automotive applications demand higher performance and operating requirements, yet these requirements need to be achieved at affordable cost and without compromising vehicle safety. The advantages of LFP as a cathode material include thermal stability, limited environmental impact and potential of low cost as compared to the cathode chemistries containing cobalt. Currently, solid state and hydrothermal processes are used to synthesize LFP at the industrial scale. However, they require multiple, time-consuming steps and costly precursors. Recently, a melting-casting process to produce LFP cathode material was investigated. The motivation behind this new process is the great flexibility of raw materials including chemical makeup and particle size, and the use of lower cost, commodity chemicals, with the benefits of increased kinetics in the molten state and energy efficiencies leading to overall process cost savings. Also, if successful this process could represent a novel application of conventional casting. Melting lithium-, iron- and phosphorus-bearing precursors in near stoichiometric ratios and casting LFP material that forms around 1000 °C requires fewer processing steps.

Mar 1, 2018

By Animesh Jha

Univariant diagrams are constructed for the reduction of nickel and cobalt oxide and sulphide minerals. The results from the carbothermic and hydrogen reduction of sulphide minerals are compared. The importance role of lime and calcium sulphate in controlling the emission of sulphurous- gases during reduction reaction is also explained. The mechanism of carbothermic reduction of nickel sulphide is explained by examining the sulphur exchange and reduction reactions. The phase equilibrium relationships that determine the formation of multicomponent liquid are characterised. Also the governing equilibria for inert atmosphere calcination- roasting of nickel and cobalt sulphide minerals are also described for the metallization of nickel and cobalt.

Jan 1, 1993

By José R. de Tenorio

The aim of the present work was to investigate the reduction process of MnO~FeO-Si02 slags by carbon-saturated liquid iron. The effect of the initial Mn content in the bath was explored. The initial Mn content was in the range of 0 up to 40 wt. %. The MnO content in the slag was kept constant at 40 wt. %. Tests were performed in laboratory apparatus. Samples of slags and bath were taken. In the first 5 minutes, it was observed a very strong reduction of FeO. This first step promoted a MnO-Si02 enrichment of the slag and a formation of CO bubbles, which increases the slag level. The increase ofMn content decreases the MnO reduction rate.

Jan 1, 1996

By Roma T. Dec

Many industrial wastes may require preliminary processing to change their particle size, density, surface properties or flowability to become more suitable for treatment and recycle. This can be achieved by pressure agglomeration using roll presses. In the following paper an overview of various roll press processing methods like briquetting, compacting, compacting-granulating or densification is presented together with basics of process and equipment design. The emphasis is focused on major factors influencing compaction process and responsible for pressure build up and final product quality. Finally, two examples of roll press application for briquetting of steel plant wastes and compaction of alumina base catalyst tailings are introduced.

Jan 1, 1996

By Han Yihua, Zhang Caijun, Zhu Liguang, Zhang Qingjun, Wang Shuoming, Wang Yan

An industrial test on 210 t converter-LF-CC production line on high heat input welding shipbuilding structure steel DH36 has been taken in a factory in north China, the effect of adding microalloy elements V and Mg on casting billet microstructure has been researched. It was found that when the composition of V was between 0.03 and 0.05% and the composition of Mg was between 0.002 and 0.005%, a large number of acicular ferrite precipitate in austenitic crystal in as-cast structure and cross into a net structure. The inclusions size which induced intra-granular ferrite are mainly less than 4 lm, especially those between 2 and 3 lm account for 50.80%, in these inclusions the composite inclusions mixed with Mg accounted for more than 60%.

Mar 1, 2017

By E. Fregeau-Wu

The major obstacle in recycling steelmaking slags to the blast furnace is their phosphorus content. Removal of the phosphorus, which is primarily associated with the silicate and phosphate phases, would allow for greater recycle of these slags for their iron, manganese, and lime contents. Calculations show that separation of the silicates from the oxide phases would remove nearly 90% of the phosphorus from the slag. The variable grain size of the as-received slag made liberation by fine grinding difficult. Therefore, slow-cooling experiments were undertaken to improve the grain size distribution. The grain size distributions were determined using in-situ image analysis. The samples were ground to their apparent liberation size and high gradient magnetic separation was used to separate the magnetic oxides from the nonmagnetic silicates and phosphates. Liberation analysis and modeling was performed on selected separation products for discussion of benefication characteristics.

Jan 1, 1995

By D. M. Jones

In May 1999 the first campaign of the BHP San Manuel flash smelting furnace (FSF) will be concluded after having set world records for both campaign length and tonnage smelted for an Outokumpu copper flash smelting furnace. This paper reviews planned process and equipment modifications including: The installation of a new 36,000 mt concentrate storage facility; replacement of the existing dryer electrostatic precipitator with a baghouse; modification of the FSF dry charge bin and feed system to achieve mass flow and uniform feed to the concentrate burner; modifications to the FSF and its ancillary cooling systems; modifications to the waste heat boiler and offgas handling system to increase gas handling capacity and improve process efficiency;- and improvements to the FSF fugitive gas collection system. A brief review of the planning and execution of the scheduled 45 day shutdown is also given.

Jan 1, 1999

By Giovanni Principi

The activity of the ?Hydrogen Group? of Padova University, addressed to the study of materials for solid state hydrogen storage, is illustrated. Various Mg-based materials have been considered and are being studied: a) MgH2 and 0.5% mol Nb2O5 mixture ball milled under argon atmosphere; b) Mg-Ni-Fe intermetallic compounds prepared by short time ball milling of ribbons obtained by melt spinning and by long time ball milling of a mixture of MgH2, Ni and Fe powders; c) MgH2 ball milled in argon with Mm-Ni-Al (Mm = La-rich mishmetal) and Zr-Cr-Fe catalyst alloys. All the samples have been structurally characterized by X-ray diffraction (Rietveld refinement) before and after hydrogen absorption/desorption cycling and tested with a Sievert apparatus as regarding their thermodynamic and kinetic properties.

Jan 1, 2006

By Denise Corrêa de Oliveira

Common dry batteries use zinc as the negative electrode. Producers commonly use additives such as mercury to prevent corrosion and to increase the mechanical resistance of the zinc anode. Alkaline batteries also contain it, as an anti-corrosive agent. When mixed with the common municipal solid waste, heavy metals as zinc and mercury pollute soil and ground water supplies, moving to the food-chain and affecting human health. Due to these possible damages, this kind of waste must be properly disposed, or recycled. Thus, even in low amounts (ppm) in batteries, mercury has to be eliminated or, at least, its content should be reduced. This work presents the use of pyromettalurgical processes, to reduce mercury content and recover zinc. The tests involved batteries treatment at temperatures from 300° to 1000°C. Mercury is eliminated up to 650°C, and zinc is evaporated at higher temperature treatment. C

Jan 1, 2001

By T. J. White

A synthetic Mineral Immobilization Technology (SMITE) has been developed for stabilizing municipal and hazardous waste incinerator ash. Tailored additives are introduced to the ash in a' first stage that pre-stabilizes all the toxic metal components in non-volatile forms. and in a second pyrometallurgical stage, these are converted to insoluble mineral analogues. It has been found that a combination of apatitie. spinal, anhydrite and monazite can immobilize all the ash components at high waste loading and high density. Typically the stabilized products contain in excess of 50 wt% ash and have densities of 2.5- 3.0 g.cc-1. Toxicity Characteristic Leach Procedure (TCLP) testing has demonstrated that the products well satisfy regulatory requirements. The cost of production and disposal of SMITE waste forms in 2-5 less expensive than. convential methods of solidification/stabilization. This paper will describe the principles of SMITE design for ash stabilization, outline the fabrication procedure, and present comprehensive microstructural and chemical data to validate waste form performance.

Jan 1, 1996

By Jack S. McPartland

The recent developments on the concentration and recovery of gold from leached gold thiosulfate solutions by solvent extraction, reduction-precipitation, and electrochemical deposition are reviewed in this paper. Alkyl phosphorus esters have been found to extract gold only in alkaline thiosulfate solutions, The recovery of gold increases with thiosulfate concentration in the aqueous phase and with alkyl phosphorus esters concentration in the organic phase with aliphatic hydrocarbon diluents. The addition of ammonia improves the extraction. The extraction of gold with amines in either aliphatic or aromatic diluent decreased in the following order: primary>secondary>tertiary amines. Increase in the extractant concentration at high pH increased the extraction of gold. At pH < 9, the primary amine, RR&apos;CHNH2 with 1&apos;9-23 carbon atoms is the main extractant with TBP as the synergistic reagent and at pH >9, the primary amine shows a synergistic effect on the extraction of gold&apos; with TBP. TheAu(I) ions in thiosulfate solution are reduced by sodium borohydride (SBH) to metallic gold, with particles in the sub micron range, At an SBH/ Au ratio of 6.25, pH = 6, and at room temperature, the I e ppm Au(I) in a solution of ] 0 gil thiosulfate was completely reduced to metallic gold in about 60 minutes.

Jan 1, 1999

By Kazuyuki Kakegawa

The sintering characteristics and the change in the compositional distribution in the PbTiO3-PbZrO3-Pb(Mg1/3Nb2/3)O3) system during the sintering process by spark plasma sintering (SPS) method were examined. They were compared with those by a normal sintering method. The densifieation by the normal sintering was slow even at high temperatures. When SPS method was employed, much lower temperature and shorter period resulted in sintered bodies having almost the theoretical density. As expected in normal sintering, the compositional distribution decreased as the sintered density increased. On the contrary, the change in the compositional distribution by SPS was much smaller than that in the normal sintering. This sintering characteristic of SPS suggested a possibility of fabrication of sintered material having a desired compositional distribution.

Jan 1, 2003

By J. P. Evans

The modem &apos;copper smelter today utilizes tonnage oxygen for smelting concentrates. ,generating a high strength S02 off-gas leaving the smelter vessel. This gas stream. which also contains any unreacted oxygen, plus CO2; N2 and H20. also carries with it the volatilized portion of heavy metals in the feed, plus partly oxidized sulfide concentrates, The time/temperature history and subsequent treatment of this off-gas stream emerging from the smelting furnace exit up to the acid plant can influence the partitioning and segregation of heavy metals, in the off-gas circuit. Depending on this history. the type and characteristics of the chemical and physical reactions which occur in the gas handling system &apos;can be influenced. This fact can also be used as a tool to adjust the separation of copper from heavy metals. In this paper, the impact of different time/temperature histories of the gas, due to different furnace geometries and design. on the subsequent formation and characteristics of the smelter dust is examined. Based on the available data. several case histories drawn from examples using both bath and flash smelting technologies are analyzed from this perspective.

Jan 1, 1992

By J. P. Evans

The modem copper smelter today utilizes tonnage oxygen for smelting concentrates, generating a high strength S02 off-gas leaving the smelter vessel. This gas stream, which also contains any unreacted oxygen, plus C02, N2 and H20, also carries with it the volatilized portion of heavy metals in the feed, plus partly oxidized sulfide concentrates. The time/temperature history and subsequent treatment of this off-gas stream emerging from the smelting furnace exit up to the acid plant can influence the partitioning and segregation of heavy metals in the off-gas circuit. Depending on this history, the type and characteristics of the chemical and physical reactions which. occur in the gas handling system can be influenced. This fact can also be used as a tool to adjust the separation of copper from heavy metals. In this paper, the impact of different time/temperature histories of the gas, due to different furnace geometries .and design, on the subsequent formation and characteristics of the smelter dust is examined. Based on the available data, several case histories drawn from examples using both bath and flash smelting technologies are analyzed from this perspective.

Jan 1, 1992

By Dale Zacherl, Andreas Buhr, Rainer Kockegey-Lorenz

"The microporous calcium hexaluminate insulating material SLA-92 has been introduced as an alternative to refractory ceramic fiber and other insulating refractory materials. Key properties associated with this product include: high chemical purity, long term high temperature stability up to 1500 °C, low thermal conductivity up to 1500 °C, and high thermal shock resistance. The properties of the new material and various applications in the steel and ceramic industries have been reported in previous papers. The current paper summarizes the industrial application experiences with innovative refractories based on SLA- 92 and discusses potential new applications in various manufacturing as well as energyrelated industries.IntroductionSLA-92 was introduced to the refractories industry in 1998 by van Garsel, et al. [1] as a new insulating raw material for high temperature applications, followed by investigations [2] of long term temperature stability for this new lightweight aggregate up to 1500°C.SLA-92 was developed as an innovative alternative to commonly used refractory ceramic fibers. It has unique properties regarding chemical purity and mineral composition and is a microporous, silica-free calcium hexaluminate (CA6 – mineral name: hibonite)."

Jan 1, 2010

By T. S. Krishnan

Among the established permanent magnets, SmCo5 magnet occupies the foremost position as it offers a unique combination of high energy product, coercivity and curie temperature. The SmCo5 magnets are thus extensively used for high field applications. These are also best suited for use in environments where high demagnetising field and high temperature are operative. Also, for applications where high performance and miniaturisation are the over-riding considerations, the choice again falls on SmCo 5 magnets. The main deterrent to the widespread use of SmCo5 magnet is its high cost. Both samarium and cobalt metals are high priced, and the magnets prepared from their directly melted alloy are thus naturally very expensive. An alternate process involving calcium reduction of their oxide intermediates has, therefore, been studied and the alloy prepared by this process has been evaluated and found satisfactory for magnet production. The process essentially involves compaction of the charge mix containing samarium oxide, cobalt oxide (or metal) and calcium metal and&apos; reduction of the charge compact at 1000-1300°C in hydrogen atmosphere, followed by water and acid leaching, drying and classification. The calcium reduction process offers three distinct advantages over the conventional melting processes: (i) The oxide intermediates are relatively cheaper and do not pose any handling problems. (ii) The operation temperatures are comparatively lower and hence precise composition control is possible as samarium losses due to volatilisation

Jan 1, 1989

By V. Blet

Rare earth elements (REE) are regarded today as highly critical raw materials but currently lack suitable recycling processes. A combined hydro- and pyrometallurgical process aimed at REE recovery from used NdFeB permanent magnets was recently developed by the CEA. The process integrates the physico-chemical treatment of magnets, followed by a solvent extraction step for the recovery and intra-REE separation using a selective extractant. A subsequent pyrometallurgical treatment via molten chloride salt electrolysis allowed the isolation of pure Dy metal. Technical-economic assessment and life-cycle analysis were also conducted. Following this first successful demonstration, a new project aimed at the recovery of REE from end-of-life nickel-metal-hydride batteries is currently being developed in association with industrial and academic partners. The project aims at evaluating from an experimental and economic perspective different processes converging at the production of value-added products such as cermet materials for catalytic applications, purified REO concentrates, or metallic alloys.

By Djona M. Gaballah I.

Selective chlorination of unroasted and roasted spent hydrorefming catalysts was studied between 300 and 600°C using the following gas mixtures : C12+CO, C12+N2 and CI2+air. Such materials contain Co, Ni and Mo compounds supported by alumina and/ or silica. They also contain variable amounts of V compounds, C, S, etc., accumulated during the life time of the catalyst. Direct oxychlorination of the C+S rich sample allows higher extraction rates than those obtained by the carbochlorination of the same roasted one. It seems that the roasting step doesn&apos;t favor the economic metals&apos; recovery. Results of the chlorination of C+S poor spent catalysts, in the presence of CO, in the chlorinating gas mixture, or of carbon added to the sample, were comparable. Cobalt and nickel chlorides were .extracted from the chlorination residues by their dissolution with acidified water, whereas molybdenum and vanadium chlorinated compounds were recovered by selective condensation from the vapor phase. The recovery rates of valuable metals as well as the selectivity were higher for the chlorination of spent catalysts than results obtained by the hydrometallurgical processing of the same sample. Results of the scale-up of the oxychlorination of the unroasted sample confirmed those of the laboratory scale. The global recovery rates were about 88 pct of cobalt, 93 pct of molybdenum and 76 pct of vanadium. The carbochlorination was applied to the recovery of W and Ti from Denox catalyst that is a carbon and sulfur free one. Recovery rates higher than 99 pct at temperatures lower than 500 °C could be obtained. This may indicate that the chlorination process can be applied to the treatment of various industrial wastes or by-product containing transition and/or refractory metal compounds A flow - sheet for the pretreatment of these materials is proposed.

Jan 1, 1995

By R. N. Reddy

The Pseudo capacitance of layered type Mn02 electrode material for electrochemical capacitors (EC&apos;s) was investigated. MnO2 was synthesized in our laboratory. Mn02 was prepared from heating of KMn04 at 300°C in air. Cyclic Voltammetry (CV) experiments were carried out using three electrode system, Saturated calomel electrode as reference electrode, platinum mesh as a counter electrode, and MnOz composite material mounted in a platinum mesh used as a working electrode. Two kinds of composite working electrode materials were used, one was mixture of MnOz and 25 wt% acetylene black, while the other was MnOz, 25 wt% acetylene black and 25 wt% carbon. All the experiments were carried out at 25OC. A maximum specific capacitance of 130 Fig and 118 Fig were observed at the scan rate of 2 mV/s and 20 mV/s respectively in 1M KC1 for composite electrode made with carbon. Results obtained in this study are compared with that of other electrode materials.

Jan 1, 2002

By I. M. Santos Moraes

Achieving high current efficiencies when operating at high current densities is a goal for every refinery, whether conventional or permanent cathode technology is employed. To obtain higher current efficiency at increased current density at Caraiba&apos;s Tankhouse, the production team decided to change the cathode cycle from eleven to thirteen days, reducing cathode cycle to one per anode cycle. The idea was to reduce the anode-cathode spacing and consequently reduce the potential for short-circuiting them. With respect to current efficiency, the overall result was not much better than that obtained with the normal operating conditions. A new attempt to obtain higher current efficiency at high current density was implemented by going back to two cathode cycles per anode cycle, this time reducing cathode life to ten days. This approach yielded the highest current efficiencies. This paper presents the data generated with the three operating conditions: normal practice, a single cathode cycle per anode cycle, and two cathode cycles per anode cycle with a reduced cathode cycle time. It compares the productivity achieved with each set of operating conditions. An analysis of the main operating parameters as well as the advantages and disadvantages involved with each condition is also presented for future reference.

Jan 1, 1999