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By Fathi Habashi

Solid gas reactions of metallurgical importance can be classified into three groups: Physical processes, e.g., drying and sublimation Chemical processes which may be an addition or a thermal decomposition reaction Electrochemical processes which may be addition, oxidation-reduction, or displacement reactions. Examples are given and the role of the boundary layer is emphasized.

Jan 1, 1996

By Luben Savov

This paper presents recent research works on the removal of the tramp elements Cu, Sn, Zn and Pb from steel. The evaporation of Cu and Sn in iron-based melts treated at reduced pressure of the gas phase was studied in a vacuum induction melting furnace. The effect of chamber pressure, temperature and melt composition was investigated. Since the main source of contamination of steel with Sn and Zn is the recycling of tinplate and zinc coated steel, respectively, possibilities for the removal of meta1ic coatings in a scrap pre-treatment stage were studied, too. Tin was removed in the temperature range 400-5S0°C by treatment with reactive gases featuring high sulphur potential. Zinc can be removed by evaporation or by a combination of thermal and mechanical treatment. The paper discusses the thermodynamics of Pb in carbon-saturated iron melts, too.

Jan 1, 2001

By A. V. Tarasov, V. M. Paretsky

"Based on theoretical and experimental studies into the specific features of the mechanism, kinetics, aerodynamics and heat transfer parameters of the flame-type oxidation of metal sulfides in a stream of technical-grade oxygen, a three-dimensional deterministic mathematical model of an oxygen-flame smelting furnace has been developed on the basis of the zonal method for computation of heat exchange. The model is presented in the form of equations taking into consideration the radiation component of the selective radiation, the convection component of mass transfer between the space and surface zones, heating of charge particles due to heat conductivity, accretions formation on a multi-layer refractory lining with inserted cooling elements. The adaptation of the model for a full-scale furnace has demonstrated the possibility for its use for computation of main smelting process parameters. Multifactor model investigations were conducted and the results obtained were applied using statistical methods for development of a simplified computational regression model describing the interrelation of the main output parameters: temperatures of flame, lining, slag and off-gas; heat fluxes to the lining; thickness of accretions; heat removed by cooling elements; copper content of matte. On the basis of this model, a block diagram of the algorithm was developed for control of the thermal conditions of the furnace, as well as the control algorithm itself.IntroductionThis paper presents the results of an integrated modeling and development of principles for control of copper smelting process using as an example the oxygen-flame smelting process (KFP) for treatment of sulfide concentrates at the Kovoguty Krompahy copper smelter (Slovakia) with a capacity of 20,000 tpy of copper."

Jan 1, 2001

By B. M. Fisher

A process for making electrolytic copper of high quality from copper flotation concentrates is described. The concentrates are first slurried and then subjected to a high-temperature, high-pressure, oxidation-leaching operation under controlled conditions. The resulting slurry from the oxidation-leaching operation is cooled or flashed to atmospheric pressure and then subjected to a solids-liquid separation. The separated liquor, containing the recovered copper values, is cooled and then fed to an electrolytic deposition operation where metallic copper cathodes of high purity are produced. The spent electrolyte is then subjected to a sulfide treatment to precipitate the residual amounts of copper not deposited in the electrolytic cells. The precipitated copper sulfide is recovered and recycled in the form of a slurry to the initial stages of the process.

Jan 1, 1976

By Beatryz Mendes, Leonardo Pedroti, Afonso Azevedo, José Maria Carvalho

The dregs is a waste from the cellulose production, and its reuse is an effective way to reduce environmental impacts. Researches have already been done to incorporate it into building materials. The present work aimed at incorporating dregs in the production of mortar to replace hydrated lime. The methodology adopted was the Simplex network with ten sampling points, varying the amount of cement, sand, and dregs. Each mix was submitted to flexural strength, compressive strength, apparent mass density and water absorption by capillarity tests. The results were analyzed by the software Minitab, obtaining the influence of each component in the mixture. The best results were observed in mixes with a higher proportion of cement and less of residue when it was analyzed the flexural and compressive strengths. Larger rates of apparent mass density and water absorption were noticed with a greater amount of dregs. The experimental design also allowed the obtainment of mixture ratios from predetermined values of the tested properties and indicated that the addition of dregs in mortar could be an alternative to civil construction.

Mar 1, 2018

By Gregor Kücher

Lack of basic knowledge on the semi-direct recycling methods for hard metals hinders the application on an industrial scale. However, advantages like reduced expenses and lower environmental impact draw interest at future potentials. Consequently, this report aims to offer insight into the influence of varying bulky hard metal substrates during their lixiviation in acidic media with an oxidant. The statistical software Modde 11 assisted in the development of a design of experiments (DOE) for evaluation of the impact of average grain size, binder and tantalum carbide (TaC) content on the leaching characteristics. The other experimental parameters were constant. Among them were temperature, solution concentration and quantity, duration and substrate surface exposed to liquid volume. Eventually, prediction plots and factors of the computed model equation describe the effects of varying substrate qualities on leached binder metal and selectivity.

By M. E. Myers

An experimental program is being carried out to determine the thermodynamic characteristics of zinc solubilization in high-temperature iron and iron-carbon alloys. Two versions of an isopiestic technique are being used, with zinc at a lower temperature being equilibrated with pure iron foils or molten iron-carbon alloys at a higher one. The lower temperature sets the partial pressure of zinc vapor, and thus the activity relative to a given reference state. Initial results show Henrian behavior for dilute zinc solutions in austenite and a molten 4.6% C alloy, with unit-pressure solubilities in pure Fe that closely match the predictions of Wriedt.

Jan 1, 1992

By K. W. Cathrine Solem

Filtration of liquid aluminium is widely used in the industry for the removal of inclusions, and Ceramic Foam Filters (CFFs) are often the filtration media of choice. It is known that PH3 (phosphine) can be released from used phosphate bonded CFFs when in contact with water. Additionally, there is a need of an improved understanding of the thermal stability and the chemical reactivity of these types of filters, as there is limited information available in the public domain. In the present preliminary study, three CFFs, i.e. Substrate 1–3, with varying AlPO4 (aluminium phosphate) content were studied under controlled conditions. Samples of the substrates, as produced and in contact with 5N pure aluminium, were heat-treated in a vacuum induction furnace at 850 °C and 1300 °C, as well as thermally studied at 850 °C using a Differential Scanning Colorimeter connected to a Thermogravimetric Analyser (DSC-TG). All tests were performed under an inert atmosphere of argon (Ar). Mass changes of ∼0.001 % were registered for the pure substrates, and 0.003-0.10 % when in contact with aluminium. In the latter case, diffusion of P (phosphorous) from the bulk of the substrate to the interface was established to have taken place. A colour change, from white to orange/brown, was also observed at the interface, which is a clear sign that a chemical reaction has taken place. As a result, the thermal stability of the substrates can be questioned under present conditions.

By Wangzhi Zhou, Jian Xu, Jing Zhang, Xuecheng Gong, Mingsheng He, Guohua Xie

Graphite, which has a unique stack structure that enables a small friction coefficient, is used as one kind of the best hearth rolls to support and convey silicon steel strip in continuous annealing furnace. However, the buildup formation in/on the surface of carbon sleeve has always been a worldwide difficulty in the silicon steel industry. Based on the analysis of the microstructure, topography and composition of the buildups, combined with simulation experiments, the mechanism of forming buildups is discussed. The results show that buildups experience the process from nucleating to growing-up, and buildups are formed by nano liquid phase sintering (NLPS). Meanwhile, some countermeasures to reduce or prevent the formation of the buildups are proposed.

Mar 1, 2018

By Carlos M. Fontes Vieira, Ruben J. Sanchez Rodriguez, Carlos E. Gomes Ribeiro

"In this study we attempted to model a response surface for the apparent dry density of ternary blends of calcitic marble particles. The crushed marble was divided into three granulometric ranges. Simplex network methodology was used to determine the mathematical relation between granulometric ranges and apparent dry density (ADD) of particle mixtures. A highly significant regression was obtained and the simplex network methodology proved to be able to predict high packing particle compositions.IntroductionProblems with packing and expected porosity of particles are common and widely recognized to be important in terms of both fundamental physics and engineering applications. For example, densification of a powder mass is important in the shaping of solids in ceramics, powder metallurgy or composite synthesis; chemical processes such as solid-liquid separation (sedimentation, thickening and filtration), raw material handling (stockpiling, blending, drying, storage and transportation) and pyrometallurgical processes (agglomeration, coke making, ore sintering, blast furnace iron making and new iron making processes) [1,2].Many factors can affect particle packing, but in practice, there are three main factors: (dimensionless) particle size distribution, particle shape and absolute particle size [2].Geometrical and practical methods were developed to predict properties in mixtures. Zou, Gan and Yu [2] present a paper treating a prediction of the porosity of multi-component mixtures of cohesive (fine) and non-cohesive (coarse) particles. Bahiense et al. [3,4] used a simplex network to determine a mathematical model for obtain the optimal compositions between aggregates to a greater packing of a ternary particles mixture. Despite these techniques for predicting particle packing, some studies in particulate composites production don't present clear criteria for choice of particle distribution [5,6]. As the best particle packaging depends on the size, distribution and shape of these particles, individual models can be constructed for specific combinations of these factors."

Jan 1, 2014

By J. A. Innes

"""The oxygen, next uniting with the carbon, sent up an ever-increasing stream of sparks and a voluminous white flame. Then followed a succession of mild explosions, throwing molten slags and splashes of metal high up into the air, the apparatus becoming a veritable volcano in a state of active eruption.""IntroductionHenry Bessemer F.R.S(An autobiography, 1905)Thank you Mr Chairman for the opportunity to speak: at this, the opening session of your International Symposium on the subject of ""Injection in Pyrometallurgy"". Judging from the list of papers to be presented over the next three days, the Symposium promises to provide a most valuable addition to our existing knowledge base in what is now an extremely active area of R&D investigations. Whilst we have obviously come a long way since Sir Henry Bessemer's pioneering experiments of the mid-19th century, there is still much for us to learn.Most importantly, the Symposium offers a further opportunity to acknowledge the many significant technical contributions made in this field by the Organising Committee's special guest, Professor Howard Worner - one of this country's most respected research leaders.When first approached to give this talk I had two areas of concern. Firstly, I was not entirely clear just what injection metallurgy was meant to cover. How should the overall scope of this particular subject be defined?My second concern related to Howard Worner himself - a man for whom I have the highest personal regard and who, in fact, played a most influential role in respect of shaping my own career. Having already spoken about Howard's achievements on earlier occasions, I wondered what I could sensibly add.Notwithstanding these personal reservations, I am delighted to be here with you this morning. If my thoughts on the meaning and scope of injection metallurgy appear to be slightly off-course, and if Howard should perhaps recognise some repetition in my remarks, then I hope I can be forgiven."

Jan 1, 1996

By Mariana M. Arantes, F. R. Valenzuela-Díaz, Olgun Guven, Vijay K. Rangari, Julyana Santana, Esperidiana Moura

Nowadays, the development of polymeric materials reinforced with residues of vegetal fibers is becoming popular for application in different segments, from the automotive to the civil construction and furniture industry. Vegetal fiber residues may be used as reinforcement of the recycled polymer materials, for instance, to produce foams to packaging or to thermal and acoustic isolation for green building application. This work is focused on the development and characterization of recycled-HDPE/EVA foam reinforced with fiber residues from babassu coconut epicarp. Firstly, composites based on recycled-HDPE/EVA blend reinforced with babassu coconut fiber were obtained by melting extrusion process. The composites were then extruded in a special single screw for foaming. The foam samples were submitted to mechanical tests, density measurement, DSC, TG, and FE-SEM analysis.

Mar 1, 2018

By Yu-ki Taninouchi, Toru H. Okabe

Among platinum group metals (PGMs), Pt, Pd, and Rh are the essential constituents of automotive catalysts. Recovery of PGMs from catalyst scrap is important, but it is difficult because PGMs are chemically stable and are present as minor components in the scrap. A vapor treatment method using FeCl2 vapor to alloy PGMs with iron, enabling subsequent magnetic separation, is developed and tested on Pt, Pd, and Rh wires.

Mar 1, 2017

By G. Richards

The Trail smelter of Teck Metals Ltd. produces about 90,000 tonnes of lead per year through two stages of refining following KIVCETTM smelting. Bullion from the KIVCET furnace is first treated in a pyro-refining plant in preparation for Betts electrorefining which makes 99.99% pure lead. Pyro-refining consists of number of integrated unit operations to remove primarily copper, arsenic, antimony and tin. The operation of this plant to meet the specifications for electrorefining requires attention to bullion management and selective use of reagents. The processes used for pyro-refining are reviewed in terms of chemistry and control.

By S. Sugiyama, M. Kiuchi

"New metal working processes, such as the mashy-state mixing, mashy-state forging, mashy-state rolling and mashy-state extrusion are developed and applied to manufacture the so-called particle reinforced metals, fiber reinforced metals, particle reinforced cladding metals and so forth. These metal-ceramics composites are made of metal sheets, metal powders, ceramics particles and ceramics fibers. The mashy-state processes are also used to work those composites into bars, wires, tubes, plates, sheets, machine parts and other products. The working conditions necessary to manufacture sound composite products are clarified and the mechanical properties of the products are investigated. Through the investigation, it becomes clear that the mashy-state processes are useful and effective to manufacture metal-ceramics composites. It is al so known that these processes may be applied in various ways to development of new metal matrix compounds. IntroductionThe so-called metal-ceramics composites and processes to manufacture them are now being widely investigated in order to comply with increasing demands for new materials with novel and excellent mechanical properties and functions. The metal-ceramics composites are expected to have superior characteristics with respect to the elastic modulus, hardness, anti-wear resistance, high temperature strength and other mechanical properties to those of conventional metallic materials.The present authors ha v e been investigating into new metal working processes which are based upon the characteristics of metals and their alloys in the mashy-state. In the mashy-state, the metal (or alloy) includes both of the solid and liquid components. According to the fact that the partial melting takes place and the liquid component usually exists at grain boundaries, the metal in the mashy-state has quite different mechanical properties from those of the metal in the solid-state. Because of that the bonding force among grains is very weak due to the partial melting occurred at grain boundaries, the mashy metal has distinctively low flow-stress and high deformability. The mashy metal splits into grains or particles and sticks to others very easily. It is so soft as to be stirred up just like a lump of sherbet, but it is sufficiently viscous to be mixed up with other materials, such as ceramics particles and ceramics short-cut fibers."

Jan 1, 1988

By G. R. Waters

NMR360 is developing a suite of chloride-based metals extraction processes, with the first commercial operation scheduled for commissioning late in 2018. It is critical, therefore, that with the introduction of any new technology, that the circuits do not suffer from mechanical failures which will compromise the operation. Although chloride leaching is at atmospheric pressure and relatively low temperature, the main challenge is preventing corrosion, since the high proton activity makes even a small amount of acid behaves as though it were concentrated. An additional challenge in concentrated chloride circuits is the potential for solids precipitation. In this context, therefore, correct valve selection is crucial, and NMR360 has partnered with CGIS to ensure that the Severe Service Valves (SSVs) needed will perform over and above the definitions of the Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry. This paper outlines what the minimum requirements are for SSVs in chloride leaching applications, drawing on five decades of industry experience from one of Canada’s leading valve experts.

By Zhihe Dou, Jiang Liu, Ting-an ZHANG, Yukun Huang

The paper aimed to propose that mixed rare earth concentrate was decomposed by pressurized calcification where mechanical milling was applied simultaneously (also known as mechanochemical calcification). The bastnaesite and monazite were both decomposed by OH−, where released rare earth formed RE (OH)3, released fluorine and phosphorus formed CaF2 and Ca2P2O7. Then, the calcified slag was leached by diluted hydrochloric acid to extract rare earth and both recover fluorine and phosphorus. The phase transformation regularity, the behavioral trends of rare earth, fluorine and phosphorus were investigated. Results showed under the optimal conditions of ball to material weight 80:1, the calcification temperature 250 °C, the liquid-solid ratio 5:1, the leaching yield of rare earth reached to 92.16%, Ce was 86.47%, La was 97.58%, Nd was 99.99% and the mass fraction of F, P entering into calcified liquor were 8.27, 0.21% respectively. The micromorphology of the mineral has a transition from dense to fluffy, and then became dense again.

Mar 1, 2018

By Abdulkader M. Abed, Shadia J. Ikhmayies, Bothina M. Hamad, Belal S. Amireh, Yulia Valery Meteleva

This work is a first step on the way to characterize raw sandstone in Jordan, and to extract silica and silicon for the use in solar cells and other industries. Seven samples of raw sandstone were brought from Disi in Jordan. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray fluorescence (XRF). The XRD diffractograms showed that silica is the main constituent of the samples, and two samples contain Kaolinite Al2(Si2O5)(OH)4. EDS reports showed that all samples contain aluminum and carbon, but some of them contain calcium. XRF measurements revealed that some samples contain more than 97% silica, while one sample contains more than 90% silica, and the main impurity is Al2O3. FTIR revealed the known bands of silica, and this sandstone is free of organic compounds impurities.

Mar 1, 2017

By Tracy Morris, Shijie Wang

Preparative Continuous Annular Chromatography, or P-CAC, is an innovative separation technology, a unique approach to high-performance chromatography for the separation of PGM component mixtures from solutions. P-CAC consists of inlet/distribution head and outer/inner cylinders, and bottom plate/fraction-collection as well. P-CAC has been applied in biotechnological and pharmaceutical downstream processing. This was the first time to explore an efficient PGM separation and recovery at the Copper Refinery. Laboratory trials with using a chloride solution for raffination for PGM are described and the tests results are presented in this paper.

Mar 1, 2017

By A. Haxhiaj, Mitovica, E. Haxhiaj

"The paper discusses problems encountered during the release and possibility of using the thermal gas quantity Mathematical models are used to calculate the positive thermal effects of the gases and losses of thermal quantity with gases in the melting process of electric furnaces. The paper discusses in details the percentages of CO, CO2, H2S, O2 and the humidity in gases and their impact on the technological process in electrical furnaces in Drenas. The paper also confers the quantity and temperature of gases, the transfer of thermal quantity and dust with gases in the environment. The paper presents the percentage of humidity in the load which is added in electric furnace for melting and its impact on thermal and environmental balance in the technological process of melting in electric furnaces. Key words: Furnace, load, temperature, humidity, gases.IntroductionNickel easily reacts with gases in the atmosphere of the furnace in which the nickel ore is processed. Such reactions can explain challenges in producing high quality nickel. Reductive atmosphere with the surrounding gases composed of sulphurous anhydrite has harmful effects on the production of nickel. This is mainly due to solubility of hydrogen as well as nickel oxide in the melted metal. Nickel reacts with carbon monoxide and forms carbide of nickel and nickel oxide which dissolve in the melted metal. Carbon monoxide also dissolves in the melted metal. The presence of carbon dioxide and water vapor in the atmosphere of the furnace impact the decrease of acidity in reductive atmosphere of the furnace. The carbon dioxide reacts with nickel and forms nickel oxide and carbon monoxide. Water vapor reacts with nickel and forms hydrogen and nickel oxide that have negative impact on the structure of nickel and its alloys. In this paper the analytical and experimental analyses are proposed that lead to minimization of the negative effects of gasses and humidity in the melting process. As the practical example, the electrical furnace in Drenas is analyzed.1. The Load and Its CompositionThe basic function of the rotational furnace is drying and reductive roasting of the ore which directly is loaded into the electrical furnace for melting. It is important to mention that the degree of roasting and pre-reduction of iron-nickel oxides is reached if the roasting process of the load in the rotational furnace is done at the temperature of 900°C to 1000°C, with the reductive atmosphere in the furnace and with minimal amount of oxygen in the processing gas. The optimal process of roasting and pre-reduction of the load in its mass is around 13 wt%. With the removal of the humidity and the sterile pare of the ore, with the positive impacts in utilization of the thermal and electrical energy in the melting process in electrical furnaces."

Jan 1, 2013