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By Lisa E. Helberg

"Titanium tetrachloride is produced through the chlorination of a variety of titanium bearing ores, some occurring in nature, and others enriched in titanium content by a variety of ""beneficiation"" processes. The chlorination step can produce a variety of metal chloride impurities, such as iron chlorides and vanadium chlorides, which must be removed from the TiC14 before it can be used to produce pigmentary TiO2, titanium metal or for any other commercial use. The requisite manipulations involve both physical and chemical separations in a multi-step process. The history of various purification strategies will be discussed.TextThere are a wide range of titanium-based products available, all of which start with titanoferrous ore of some type. Two main routes are used to convert ores into products, known as the sulfate and chloride processes. The sulfate process uses sulfuric acid to digest the ore, separate the impurities, and then precipitate titanium dioxide from the resulting titanyl sulfate (TiOSO4) via metatitanic acid. This process can also supply TiOS04 for other applications."

Jan 1, 2011

By Zhou Jiemin

A mathematical model is developed to determine the economic thicknesses of refractories and insulations in rectangular furnaces, Both the heat loss cost and the lining investment are taken into account to achieve a minimum operation cost. For the sake of calculating the heat flux, the paper is particularly concerned with the simulation of the three-dimensional transient heat conduction processes in the lining and a Douglas-Rachford method is used to solve the finite difference equations, The model has been used to design an industrial electric resistance furnace operated periodically. the values of temperatures and power consumption measured from the furnace correspond with the model results.

Jan 1, 1991

By S. Yabe

The reinforcement of the annual copper production capacity to 330,000 metric tons has been attained at Saganoseki Smelter & Refinery in 1991, which is one of the largest and most efficient custom smelters in the world. Many operational improvements and technology developments have realized the increase of smelting and refining capacity without adding main facilities to the existing process. The blister copper refining and anode casting process is composed of two 400 tonnes anode furnaces and one double-wheeled casting machine with the capacity of 80 tonnes per hour. The great innovations in this process such as the finding of essential issue on the extending of anode-mould life and the development of a new anode-mould casting machine have raised the operation efficiency by 14% Now, the process is producing 38,500 tonnes per month of best quality anode in well- controlled working condition, and anode productivity per worker increased by 52%. The progress in extending anode-mould life, the mechanism of the new anode-mould casting machine and the increase of efficiency in butane reduction, that were the principal parts of many technological improvements, are described in the present paper, including some operation results.

Jan 1, 1993

By Stig Petersson

Slag from the converting of copper matte is usually recirculated to the smelting furnace. This recirculation generally causes disadvantages as magnetite-build-up in the furnace, accumalation of impurities as antimony, lead, nickel etc in the process. The treatment of converter slag in a separate furnace in order to recover the copper and nickel content would be of advantage from several points of view. At the Mining and Metals Division, Boliden, testwork has been carried out to treat converter slag from the PS-converters in a separate furnace. The tests have been performed in laboratory and pilot plant scale. The pilot plant tests have been carried out in a TBRC with charges of 5 tons. Based on these tests a full scale TBRC has been projected in order to treat the slag from the PS-converters. This slag will be reduced with copper concentrates to give a matte and a final slag low in copper and nickel. The background and data from the testwork are presented. Also the lay out, technical data and flowsheets for the projected process are shown as well as some production data from the Rönnskär smelter.

Jan 1, 1976

By Hong Yong Sohn

A thermodynamic and experimental investigation has been performed to develop a new process for converting sulfur dioxide to elemental sulfur by a cyclic process. The most promising new process is a cyclic reaction scheme involving calcium sulfide and calcium sulfate. In this process, the reaction between sulfur dioxide and calcium sulfide produces elemental sulfur vapor and solid calcium sulfate. The latter is reduced by a suitable reductant such as hydrogen to regenerate calcium sulfide. 'Experimental results showed that up to 60 % of calcium sulfide powder was converted to calcium sulfate in 10 min at 1153 K under a sulfur dioxide partial pressure of 25.8 kPa. More than 95 % of nickel-catalyzed calcium sulfate powder was converted to calcium sulfide in 20 min at 1123 K under a hydrogen partial pressure of 86.1 kPa, water vapor being the only gaseous product. Sulfur dioxide-containing streams from certain new sulfide smelting plants contain much higher partial pressures of SO2. The rate of the first reaction is expected to be accordingly higher than in the test conditions reported in this paper.

Jan 1, 2002

By Tom W. Gonzales

Magma Metals Company commissioned a 3000 tpd Outokumpu flash smelting furnace in July 1988. Through September 1992 the PSP has smelted a first campaign record 4.1 million tons of concentrate. This paper discusses modifications made to the original process equipment to overcome design flaws as well as future design changes currently under consideration.

Jan 1, 1993

By B. Yawney

A copper-nickel sulfide concentrate was leached in water at about 2000C under oxygen pressures of about 0.35 MPa. Oxidation of sulfide to sulfate was virtually complete in about 30 minutes, resulting in greater than 95% copper and 98% nickel extractions. Leaching temperature was shown to be the most important factor affecting metal extractions. Measured rates of oxygen consumption were used to develop batch kinetic data. Mini-plant continuous pressure leaching tests agreed with batch leach results. A proposed overall flowsheet is briefly examined.

Jan 1, 1976

By M. Z. Sukiennik

A static method for vapor pressure measurement up to 1450 K and above 1 hPa is presented. The method is designed for equilibrium and kinetic studies of metallic systems, including those with a chemical reaction. Application examples are given for determination of activities in condensed phases, and heterogeneous reaction rates and equilibrium constants.

Jan 1, 1993

By Dean Ilievski

Mathematical modelling of the precipitation process requires that the kinetics of crystal growth, nucleation and agglomeration be known: This paper reviews the current state of knowledge on these precipitation sub-processes (ie. growth, nucleation and agglomeration) and describes a number of experimental techniques for estimating their kinetics. The experimental methods used to generate the precipitation data and the data analysis techniques used to extract the kinetics information from the data are discussed separately. There is no universal "best" technique for determining the kinetics. However, studies on multi-crystal systems are more reliable for modelling purposes than are single crystal studies. The selection of a technique will depend on which sub-processes are present. A problem with all kinetics studies is that there is generally a large uncertainty in the estimated kinetic parameters. This stems from the scatter in the experimental data being further propagated by the mathematical techniques used to extract the kinetic parameters.

Jan 1, 1996

By F. Elgersma

Hydrometallurgical zinc winning processes ?are frequently based on iron containing concentrates which yield a goethite, jarosite or hematite residue. Jarosite or goethite are mostly stored in waste ponds which ,are lined with foil. Water percolating through the pond is withdrawn from the deposit ,and decontaminated before discharge. Despite these measures, more and more pressure is put upon zinc companies to treat their (historical) residues and to produce environmentally acceptable residues. The criterion which determines this acceptability is the potentiality of leaching out hazardous elements by natural processes. This paper provides the comparison of five different process designs for integrated jarosite treatment in a hydrometallurgical zinc winning plant leading to environmentally acceptable residues. The processes are esigned for producing 200 ktons/yr zinc and for treating 80 ktonslyr historical jarosite. Mass and energy balances are used to determme parameters such as: the energy use per ton waste treated and the amount and composition of final residues. The conclusion of the work is that. pyrometallurgical jarosite treatment integrated in hydrometallurgical zinc winning is preferable to hydrometallurgical jarosite treatment. Integrated pyrometallurgical processes lead to a ?smaller quantity of remaining hazardous residues and require less energy.

Jan 1, 1992

By S Ivanaj

Oxidation of chalcopyrite from a copper concentrate in an electrochemical cell having separate-anodic and cathodic compartments was studied by potentiodynamic, potentiostatic and galvanostatic experiments. Oxidation of chalcopyrite particles was mainly realized by in-situ electrogenerated FeIII and Cull ions. The use of an ion exchange membrane, in this experimental set, avoids the reduction of the ferric and cupric ions. The effects of particle size, current feeder potential, current intensity and pulp density were studied to optimize the oxidation parameters. Selective complete oxidation of chalcopyrite was achieved. Oxidation of pyrite was negligible. Mom than 85 % of sulfur was obtained in its elemental form. This may allow selective extraction- of copper from the chalcopyrite concentrate without sulfur dioxide emissions.

Jan 1, 1995

By E. T. White, Dean Ilievski

"Mathematical modelling of the precipitation process requires that the kinetics of crystal growth, nucleation and agglomeration be known. This paper reviews the current state of knowledge on these precipitation sub-processes (ie. growth, nucleation and agglomeration) and describes a number of experimental techniques for estimating their kinetics. The experimental methods used to generate the precipitation data and the data analysis techniques used to extract the kinetics information from the data are discussed separately. There is no universal ""best"" technique for determining the kinetics. However, studies on multi-crystal systems are more reliable for modelling purposes than are single crystal studies. The selection of a technique will depend on which sub-processes are present. A problem with all kinetics studies is that there is generally a large uncertainty in the estimated kinetic parameters. This stems from the scatter in the experimental data being further propagated by the mathematical techniques used to extract the kinetic parameters.IntroductionCrystallisation operations, including precipitation, are widely used in a number of hydrometallurgical processes to recover a desired component or to remove an undesired impurity. The goals of industrial precipitation processes are to maximise the recovery while maintaining product quality (generally product crystal size distribution, purity and morphology and product handling properties). Knowledge of the precipitation mechanisms and kinetics is invaluable for designing new precipitators or for improving existing units. The mechanistic and kinetic information is generally incorporated into mathematical precipitator models, which are then used for process design and optimisation."

Jan 1, 1996

By Tiejun Chun, Gutian Mu, Jiaxin Li, Hongming Long, Zhengwei Yu, Ning Li

The basic characteristics of iron ore, including assimilation, fluidity, cohesive phase strength and the ability to produce calcium ferrite, are often used to evaluate the sintering properties of iron ore and guide the optimization of iron ore blending. Six kinds of common iron ore used in a steel company in China were selected in this work. The basic characteristics of the single iron ore and blended iron ores were studied, as well as the difference between weighted averages of basic characteristic index of single iron ores and the real value of basic characteristic index of blended iron ore under different ore blending ratios. The results shew that the liquid phase liquidity, cohesive phase strength and calcium ferrite formation ability had a significant linear positive correlation with SiO2 content. The weighted average of basic characteristic index of single iron ore cannot fully reflect the actual blended iron ore properties. The optimization of the blending ratio can be achieved through the detection of the basic characteristics of the mixed iron ore, combined with the basic characteristics of iron ores.

Mar 1, 2018

By David N. Hanlon

The effect of high-temperature plastic deformation of the austenitic phase (y) on the subsequent phase transformation to ferrite (a) has been experimentally investigated, and modelled using a physically-based model. The effect is of importance for steel sheet, in view of me significance of the phase transformation with respect to the eventual properties of the material. In this paper the kinetics of the y ? a phase transformation has been studied after different degrees of prior deformation. The degree of deformation is varied by applying different deformation temperatures and strain rates, and by allowing a varying extent of recovery and recrystallisation. Consequently, both dynamic and static recovery and recrystallisation have been involved. The dilatometric observations on the phase transformation have been modelled using an interface-mobility model, in which the effect of the dislocation structure is introduced as an additional driving-force term. The effect of the stored energy on the nucleation process, which appears to be affected more strongly than the growth of ferrite, is examined in terms of the classical nucleation theory.

Jan 1, 2001

By Dengfu Chen, Yunwei Huang, Mujun Long, Kui Lv, Pei Xu, Lin Bai

The surface temperature of continuous casting slab in the secondary cooling zone is a key parameter of production control. However, the accuracy of radiation temperature measurement of high temperature casting slab is greatly affected by the environmental factors, such as water vapor, spray, water film and other participational medias during continuous casting process. In this paper, the radiation characteristics of water vapor and its influences to radiation temperature measurement of continuous casting slab were investigated. Based on the database HITRAN 2004 and the measuring principle of monochrome thermometer & colorimetric thermometer, the measuring errors under different operating infrared spectral wavelength were compared. Results showed that spectral region with wavelength nearby 1.0μm or 1.6μm would be the optimum for high temperature infrared thermometer used under the conditions with moist steam, water spray and water film at the secondary cooling zone in steel continuous casting.

Jan 1, 2016

By Chunlin Chen

Nickel-sulfide minerals are normally associated with copper and iron sulfides and often contain a minor amount of valuable metals such as cobalt and detrimental impurities such as arsenic. Metal losses in slag vary from process to process during the pyrometallurgical production of nickel and, depend on the feed composition, slag chemistry and operating conditions. Maximiz the metal recovery is one of major considerations to optimize operating condition for nickel smelting/ converting processes. At the same time, the deportment of minor elements between various phases during nickel smelting is of great importance by smelter operators. The Multi-Phase Equilibrium (MPE) is a thermodynamic package developed by CSIRO for simulating reactions between phases in multi-component and multi-phase systems [1]. Over the years the capability of the MPE model has been extended to cover the behavior of a large number of elements in high temperature systems. The sulfide smelting module of the MPE, which covers the minor elements such as As, Bi, Sb, Pb, Se, Te, Sn, Co and Zn, is capable of modeling the deportment of major and minor elements between various phases during nickel smelting. In this article the application of the MPE model in modelling the nickel smelting process is presented. The modelling results on the majors and minors are compared with the plant data. The deportment behaviour of arsenic in nickel smelting was analysed and the impact of slag chemistry on slag properties was modelled. These results can assist process metallurgists in exploring the optimum fluxing strategy for smooth operation and the potential practices for improving arsenic removal.

By W. W. Albrecht

I. Introduction Refractory metals like tungsten, molybdenum, rhenium, tantalum and niobium and their compounds are essential ingredients of our modern technology. Especially in purified form, they are used in special alloys, electronics, optics and ceramics. The processing route from raw material to high purity refractory metals and their compounds includes, as a prime option, the following steps: - dissolution of raw materials. - liquid liquid extraction. - precipitation of high purity intermediate compounds. - calcination/reduction to high purity oxides/metals. Especially in the first three steps, major amounts of chemicals like acids or sodium hydroxide are used and, as by-products, substantial quantities of residues and effluents are generated. The impact of environmental regulations on these by-products and the attempt to reduce or minimize the amount of residues and effluents produced will be discussed in this presentation using Ta/Nb chemistry as the example. The basis of our considerations will be the way these by-products are handled at HCST, a major, and in some cases, the biggest producer of refractory metals (tungsten, molybdenum, rhenium, tantalum, and niobium).

Jan 1, 1992

By C. Beckermann

"A diffuse interface model is derived for the direct simulation of two-phase flows with surface tension, density differences between the phases, and phase change. The derivation starts from the balance equations for a sharp interface and uses a formal averaging procedure on an atomic scale to obtain diffuse interface versions of the equations. Two approaches are considered: (i) the two phases have different velocities inside the interface and separate conservation equations are solved for each phase, and (ii) the two phases have the same velocity inside the diffuse interfuce and mixture conservation equations are solved. Based on a superposition of microscopic (atomic-scale) and macroscopic interface morphologies, an expression for the interfacial momentum source term is introduced that models surface tension effects and accounts for immiscibility between the phases.IntroductionDiffuse interface methods have been a popular tool in the direct simulation of two-phase flows [I]. In diffuse interface approaches, the interface between the two phases is characterized by a rapid but smooth transition in the properties, such as density and viscosity. Usually, a phase function ? is introduced to represent this transition, and the evolution of ? in the domain is computed from a separate equation or recipe. A unique set of conservation equations (e.g., mass and momentum) is solved on the entire domain, irrespective of the phase present, by accounting for the transition in the properties and introducing terms that account for interfacial sources. The continuum surface force (CSF) model of Brackbill et al. [2], which accounts for surface tension, is an example of the latter. The volume-of-fluid (VOF), level set, and phase-field methods are all examples of diffuse interface approaches. The major advantage of diffuse interface methods is that explicit tracking of the interface and the application of traditional sharp interface conditions are avoided. A disadvantage can arise from the artificial smearing of what is in reality an interface of atomic-scale width; however, techniques have been developed to overcome this problem."

Jan 1, 2004

By E. T. White

The population balance is one of the basic relations for a:n:aIysing particulate minera1 processing operations. It is an exact relation. The principles of the population balance are reviewed and applications in the minerals industry discussed.

Jan 1, 1996

By L. Katgerman, E. N. Straatsma, Suyitno

"Single-roll strip casting process is studied using computational fluid dynamics which takes into account fluid flow, heat transfer and solidification. The computational model is based on the conservation Jaws of momentum, energy and continuity. Correlation of strip thickness, solidification zone length, and puddle shape on single-roll strip casting of Al-1 %Mn is explored. Feeding pressure and roll speed are investigated. The results show that the··strip thickness slightly increases with pressure, similarly the length of solidification zone. The variations of strip thickness and solidification zone length with roll speed show a sharp decline for strip thickness and slight decline for the length of solidification zone with increasing roll speed. The constraint and free-jet flow have different feature in term of flow field. Severe turbulence is observed on the free-jet flow.IntroductionThe near-net shape casting of strip metals is a demand nowadays. The demand is particularly stimulated by the challenge to become more competitive through enhanced performance. The improvement in the existing processes and new innovative technologies are introduced by the metal industry to gain better product quality, more efficiency in energy consumption, low throughput, yield and operating costs [1-3].There are many advantages that can be obtained by the direct casting of strip. The most prominence is the elimination of hot rolling. Beside that the high rate of heat extraction associated with strip casting offers the possibility of a finer, Jess segregated cast structure. The microstructure will result in the improvement of mechanical properties compared to conventional material, or alternatively the opportunity of using grades of metal outside the normal range for continuous casting.The concept of single-roll strip casting has been difficult to commercialize, because of the complex interactions between fluid flow, solidification, shrinkage, and stress, which lead to serious quality problems. Besides that, the quality and the thickness of the strip are affected by the thermal properties of the strip, roll cooling conditions, roll geometry, and other process parameters. To understand how these parameters affect the strip formation, some researchers have modeled the process [4]."

Jan 1, 2004