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By Nickolas J. Themelis

The flash oxidation and smelting of mineral sulfides is a very prominent metallurgical achievement of the second part of this century. Its initial industrial implementation owes much to the work of Petri Bryk, in Finland, and Paul Queneau, in Canada. However, attempts to develop flash reduction pro- cesses, such as the reduction of iron oxide concentrates with hydrogen, have not yet been successful. The author, on the basis of experimental studies on both kinds of flash reaction systems, examines the respective rate controlling phenomena and the relative rates of flash oxidation and flash reduction.

Jan 1, 1993

By Fanke Meng

Electrolyzing oxides of titanium, aluminum and niobium could prepare high-Nb bearing TiAl alloy (Ti-45Al-9Nb) at 1500°C. The chosen electrolysis voltage is 3.5V, which is lower than reducing voltage (~4.7V) of electrolyte CaF2, but higher than that of titanium, aluminum and niobium oxides. The investigation shows that compared with traditional methods, this method for preparing high-Nb bearing TiAl alloy is of many advantages such as few steps, friendly environment, low energy consumption, low cost and high current efficiency.

Jan 1, 2009

By Florian Kongoli

The behavior of cobalt as a by-product in the NilCu smelting and converting processes effects directly the quality of the final products as well as the revenues gained from the overall process. An effective way to evaluate and predict this important behavior is thermodynamic modeling which reduces the time and the cost of experimental investigation. In this work a thermodynamic model of cobalt-containing matte phase in NilCu smelting and converting processes is presented. The model predicts a priori the thermodynamic properties and phase relations of the ternary and multicomponent matte based solely upon the optimized parameters of the binary systems. This model can be used with other models such as those of slag, metal, gas etc. to predict various aspects of cobalt behavior such as matte- slag, metal-slag distribution, etc.

Jan 1, 1999

By J. Rastas

The recovery of lead, silver and gold from existing and potential zinc process residues using a sulfidization-flotation method was investigated on a laboratory scale. The following residues were tested: neutral leach residue, high acid leach residue, and hematite residues. The sulfidization of lead and silver is carried out at low pH by the addition of a stoichiometric amount of sulfide at a controlled rate. To increase the particle size of the sulfides, seeding with synthetic lead and silver sulfides -is employed. The flotation is carried out at pH 2-4 using low pH-collectors such as dithiophosphates and dithiophosphinates. Special attention must be paid to the role of oxygen in the conditioning stage. The effect of different parameters on both the sulfidization and the flotation has been evaluated. Recoveries of 85-90, 90-95 and about 80 % were obtained for lead, silver and gold, respectively. Typically, concentrates containing 50-60 % lead, 3-5 kg/t silver and 10-15 git gold were produced.

Jan 1, 1990

By S. M. I Kytö, J .. K. Mäkinen, K. Saarhelo

"At the Outokumpu Oy Harjavalta Copper Smelter the control philosophy of the flash smelting process has been changed from the slow feed-back control to feed-forward control. This is important as the fluctuations in the flash smelting furnace matte grade and slag temperature are desired to be minimized.The system is based on a specially designed automatic sampling device and the Outokumpu Courier 20 on-stream X-ray fluorescence analyzer. A microcomputer-based Analyzer Operator Station (AOP) controls the system and calculates the process parameters for the furnace from the analyzed chemical composition and other existing data.A considerable reduction in the deviation of the matte grade and slag temperature has been gained. This has resulted in conservation of energy and refractories, lower copper losses and higher through-put in the flash smelting furnace and converters.1.0 IntroductionThe flash smelting technology for copper concentrates was developed at the Outokumpu Oy Harjavalta Smelter soon after the World War II. The incentive for this development was shortness and high price of any form of energy. The fact that smelting can be carried out autogenously, without external energy by utilizing the latent heat of sulfide combustion was known decades before, but Outokumpu Oy was the first company to take the advantage of this knowledge in practical operation. A further advantage of this technology was that the SO2 containing gases suited well for sulfuric acid production, thus minimizing the detrimental effects on the environment (1).The very heart of the flash smelting process is the reaction shaft of the flash smelting furnace (see Appendix I). Heating up of the dried feed mixture, dissociation of several compounds, ignition and oxidation of the feed take place very intensively in the reaction shaft during 2 - 3 seconds, which the fine grained particles reside in the reaction shaft. A very accurate control of the amounts of the feed materials as well as of oxidizing gases, fuel, etc. is of primary importance."

Jan 1, 1989

By Jiang Fan, Wang Haigang

"The three-dimensional complex multiphase turbulent flow in U-beam separators was simulated using the Reynolds stress equation models (RSM). To account for the effect of the stochastic characteristic of the instantaneous gas velocity on the particles, the improved Lagrangian stochastic model based on the Reynolds stress model for gas phase was adopted, which attributed to the successful prediction of the turbulence anisotropy and particle crossing trajectories effects. The interaction between the particles was also considered using the HardSphere model. To treat the particle-wall collision, the influence of the roughness of the wall on the motion of the solid particles was taken into consideration by imposing random collision angles. The result from this study not only shows the dynamic characteristics of the multiphase flow- in the separators, but also gives the relationship among the efficiency, structure and pressure losses of the separator.IntroductionCirculating fluidized bed (CFB) combustion is one of the most promising clean coal techniques. A main feature of CFB boilers is the un-delayed recycle of solid, coal and sorbant particulate, in an external loop. Separator, which is required to separate the solid particle from the flue-gas leaving the reactor of CFB, plays an importance role in the external solids recycle loop. It affects the combustion of CFB system greatly. Presently cyclone is the most commonly used as separators for CFB system and other chemical industrial processes. It provides high level of separation for CFB system for fine particles. However it suffers from some inherent disadvantages. It's volume and size is huge. Moreover, it is difficult to design and install when the CFB workload rises. The application of U-beam separators instead of hot cyclone separators in CFB boilers has many advantages. Publications indicate proposals or successful use of Ubeam separators in Swedenr11, USA 21, Russia r3land China [4]• But it is not possible to find results in the literature of detailed investigations of this new. type of separators or recommendations on the choice and calculation of an optimal design. For this reason, numerical simulation for the three-dimensional gas-particle two-phase flows with several rows of vertical U-beam elements, local in the chess order and blocking a way of outgoing from a CFB boilers dusted gases was carried out in this study."

Jan 1, 2004

By Christoph Sagadin

Corrosion mechanisms between high melting synthetic ferronickel slags and refractory were investigated. The used slags were prepared by mixing and melting of specific oxides. Substrates of the applied refractory material and specimens of FeNi slags were heated in a hot stage microscope up to 1650 °C. The experiments were performed under a defined gas atmosphere of 60% CO and 40% CO2. A further examination of the formed phases between slag and refractory occurred by scanning electron microscope. The investigations indicate that the slag penetrates between magnesia grains and partly dissolves magnesia. Spot analyses show that iron diffuses into the magnesia grains, which transform to magnesiawustite, meanwhile SiO2 forms different types of olivine like forsterite and monticellite. Thermodynamic calculations confirm the formation of these phases. The combination of practical lab scale experiments and thermodynamic calculations should finally contribute to an improvement of the refractory lifetime and performance.

By Jianguo Yin, Xuejiao Zhou, Xiaoyan Xiang, Wenqiang Yang, Xiaoli Yuan, Juan An, Wentang Xia

Low grade phosphorus-containing iron ore (LGPIO), a raw and wasted industrial solid material was used as an adsorbent to remove Cd(II) ion from wastewater. The effects of initial pH value, adsorptive time, initial Cd(II) ion concentration, adsorptive temperature and LGPIO dosage on the Cd(II) ion removal efficiency were studied. The results show that the Cd(II) ion removal efficiencies exceed 99.8% and Cd(II) ion concentrations are less than 0.10 mg/L under the pH value 6, temperature 20 °C, adsorptive time 90 min, initial Cd(II) ion concentration 50 mg/L, particle size <0.15 mm, adsorbent dosage 50 g/L and stirring speed 290 r/min. After Cd(II) ion removal reaction, the Cd(II) ion concentrations completely complies with the requirement of national discharge standard of water pollutants for cadmium and zinc industry (GB 20466-2010) (TCd(II) = 0.1 mg/L) in China. Therefore, it can be concluded that LGPIO is a new low-cost adsorbent which is suitable for the adsorption of Cd(II) ion from wastewater.

Mar 1, 2017

By SIMON TIMBILLAH

The chalcopyrite-molybdenite (Cu-Mo) flotation industry is increasingly turning to organic depressants as suitable replacements for inorganic reagents, such as NaHS, due to environmental and safety concerns as well as high consumption rates of the inorganic reagents. This presents an opportunity for improvements or design and synthesis of alternative reagents. Disodium carboxymethyl trithiocarbonate (Orfom® D8) depressant is an organic depressant with a carboxylate group on one end and a trithiocarbonate group at the other end. Fundamental results are shown regarding the interaction of the Orfom® D8 depressant in the bulk flotation of a Cu-Mo concentrate from an operating North American mine. Cyclic Voltammetry on pure copper and Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS) measurements on pure chalcopyrite with Orfom® D8 depressant treatment are also reported. Through such characterization techniques a potential adsorption mechanism of Orfom® D8 on the mineral surface was identified and its depressant characteristics in the Cu-Mo flotation systems explained.

By Gopalakrishna M. Rao

"Several industrial and government laboratories are of the opinion that solar--cell technology will grow into a billion-dollar industry by the year 2000, especially if oil prices rise again. Of the variety of materials that have been investigated as the major component of photovoltaic systems, silicon appears to have an outstanding advantage. The cost factor is the primary importance in photovoltaic development, since the technology to make silicon cells of acceptable efficiency and life time has existed since the early stage of the space program. Electrometallurgy is one of the low--cost processes for the production of silicon, since it allows direct, single-stage production from some abundant, inexpensive source materials such as silica and fluorosilicates. Among several systems, two are given particular attention, using inorganic baths with Si0 2 or K2SiF6 as the source of silicon respectively. They appear capable of development to commercial production. Conceptual designs of a commercial--scale cell for silicon production at temperatures above its melting point, and of a pilot' plant for plating silicon from an all-fluoride bath are presented. Energy ProspectsThe major changes in the world energy since the first energy crisis in 1970 have impacted on our community. When oil was $40 a barrel in the mid-1970s, we became obsessed with the energy conservation and a search for alternate energies. Even though the crude oil fell below $15 a barrel during the last several years, our energy security fears continue to haunt us. This time it is not the scarcity, but the abundance of foreign oil and the decline in the domestic production.The prospects of energy depends on the demand and supply of energy. These, in turn, depend on future energy prices, which are linked to economic factors, political events, and unforeseen circumstances. Although no one can predict the future with certainty, three energy consumption patterns used by the Ford Foundation are as shown in Fig. 1."

Jan 1, 1988

By C. Ramasamy

The tariff reductions on imports, as a part of on-going liberalisation process in India, has fueled competition within and outside India and has, in turn provided an opportunity to reach global markets. This change calls for quality upgrades and cost-competitiveness without impairing the environment. In this context, gas based processes, contributing to improvement in quality and environment as well as processes where controls are applied when gases inimical to environment are involved, are discussed in a remelt/cast-house scenario. The impact of such processes on fabrication cost of sheet ingot is seen alongwith consumption and cost of materials and compared with a world class standard plant in North America.

Jan 1, 1996

By Gary A. Wickham

In the zinc industry, this past decade has seen both prosperity and depression. Significant changes have occurred throughout the world in mining, smelting, refining, and marketing. This paper will review many of the industrywide changes of recent years and the potential impact for 1990s. In addition to an historical review of supply and demand are discussion of technology considerations for zinc and zinc based products, effects of geographical shifting of markets, and projections for the 1990s.

Jan 1, 1990

By Zhiqiang Zhou, Shengnan Zhou, Zizong Zhu, Yuchuan Ding

The effect of silicon on removal of phosphorus from high phosphorus Si–Mn alloy was investigated at 1673 K by CaO-based slag. It was found that the dephosphorization efficiency increases significantly as increasing the silicon content, which is due to the reaction between silicon and CaO at slag/alloy interface. The relation between silicon content with oxygen activity and phosphorus activity coefficient of Si–Mn melt was determined respectively as follows: lg aO = -1:55xSi - 1:67; ln rP = 9:26e xSi 0:0433 + 11:0839 The carbon content in Si–Mn melt decreases continuously with the increasing silicon content, meanwhile, the decreasing rate of carbon content becomes rapid when the mole fraction of silicon is about 0.32. Si addition is beneficial for both dephosphorization process and low carbon Si–Mn alloy production.

Mar 1, 2017

By Afshin Sadri

Acousto Ultrasonic-Echo (AU-E) is a technique developed to provide accurate measurements of the refractory lining wear in operating smelters based on the principles of stress wave propagation. The objective of the system is to provide feedback for the continuous optimization of the overall smelter operation. In some cases, the AU-E refractory lining measurements have allowed clients to extend their smelter campaigns and operate safely for several years beyond their planned reline schedule. In other cases, AU-E results inform clients of serious issues within their furnace allowing them to shut down their smelters ahead of predicted failures and possible disasters. This paper presents the results of several smelter AU-E inspections of the hearth and sidewall. These case studies demonstrate how the AU-E results were used to positively affect the smelter operation.

By I. Gaballah

About forty percent of the SOx emissions are generated during the processing of metal sulfides of Cu, Pb, Zn, Ni, etc. Although new technologies for metal sulfide&apos;s smelting allow the production of H2S04 with a reasonable cost and decrease the emissions of sulfur oxides, the generated quantity of SOx is considered as a serious threat to environment. This paper suggests alternatives for low temperature processing of complex sulfide ores or concentrates &apos;CSO or CSC&apos; under neutral, reducing and chlorinating atmospheres or their combination. At T > 400 "C, The neutral and reducing treatments allow the decomposition of pyrite and the partial recovery of sulfur as So and H2S. At 300 "C, the chlorinating treatment of CSC is fast, exothermic and allows the separation of FeC13 from the valuable elements&apos; chlorides. It also generates SyCIx that can be either reduced by H2 or hydrolyzed in presence of sodium sulfide. The recovery rate of elemental sulfur with respect to the sulfur input exceeds 90 %.

Jan 1, 1999

By R. Kola

Since more than 15 years the Waelz process at "Berzelius" in Duisburg has proved suitable for reprocessing the zinc and lead containing dust and .sludge which inevitably occur in making steel in EAF-plants. The produced Waelz-oxide is agglomerated in a hot-briquetting plant and charged to an Imperial Smelting Shaft Furnace to recover the valuable elements in form of metallic zinc and lead. In view of the actual importance of the dumping problems of the EAF wastes a description of the "Berzelius" treatment route is given but also the situation in Western Europe is illustrated. Dust from stainless steel production is successfully treated in the Scan Dust Plasma Process in order to recycle Chromium and Nickel, while the resulting Zinc-Dust is treated via the Waelz-ISF-Route. For treatment of low Zinc-containing dust, sludge and fines from integrated steelworks, pilot scale tests have been carried out successfully in the Circulating Fluid Bed in order to recover metalized iron and .zinc/lead fume. A 30,000 tpy Demonstration Plant is planned?.

Jan 1, 1990

By B. P. Sereda

The properties, characteristics and phase structure of chamotte refractories produced with the usage of mullitecorund chamotte and caoline have been given. The comparison of new refractory C-45 obtained by us and refractory C-43 produced by traditional method has done. The physical-chemical properties of refractories is reviewed. The visual porosity, density and pore characteristics of given refractories was calculated. It is established that C-45 has the less gas permeability then C-45 that gives melting units more stability. The petrographical microstructures of refractories have been done. The main phase structures and their influence on refractories properties have been observed. It is established that refractories with mullitecorund chamotte adition has more advantages then refractories gained by traditional method and can be applied to melting units.

Jan 1, 2010

By De-qing Zhu, Feng Zhang, Jian Pan

Sintering performance of a series of sinter blends with high ratio of limonite was investigated. The metallurgical performance and mineralogy of product sinter were also examined. The results show that good sintering performance could be obtained when the ratio of limonite was below 43% in the blends of iron ore fines, while good microstructure and metallurgical properties were achieved under optimum sintering conditions. In contrast, sintering performance will rapidly deteriorate when the ratio of limonite is elevated up to 63% in the blends.

Mar 1, 2017

By Jiang Diao, Yong Qiao, Xuan Liu, Tao Zhang, Bing Xie

Adding CaO into the vanadium extraction converter is an effective way to decrease the dephosphorization burden in subsequent steelmaking process. The crystallisation process of spinel is one of the most decisive factors in the subsequent extraction. The theoretical calculation results show that the temperature of the peak total crystallization rate will decrease 5K with basicity increasing 0.1. The relation between cooling conditions and grain size of spinels is also discussed. It is found that low cooling rate and high basicity benefit spinel crystal growth. And the non-isothermal crystallization kinetics results indicated that the restriction factors of spinel growth is that solid crystals accept new components from liquid-solid interfacial. While the sample was cooled down to 1250 (1523K) at cooling rate of 5K/min, the crystal growth is consistent with Ostwald coarsening grew up law, and controlled by diffusion of particle.

Jan 1, 2016

By M. R. Barkhudarov

Semi-solid metal can be formed into useful products of near net shape and high quality. Use of this method has been limited, however, because of the difficulty of working with metal in the semi-solid state, which has strong shear rate, temperature and time-dependent properties. In this paper we describe a thixotropic model and apply it to the problem of small metal droplets impacting on a flat plate.

Jan 1, 1997