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By Guolin Zheng, Jian Pan, Deqing Zhu, Xianlin Zhou

"In ferronickel production, nickel oxide and part of the iron oxide are reduced to metal by agglomeration and smelting in blast furnace. Due to the physical and chemical properties of the laterite ores, a large fraction of fines is generated during the pre-treatment stages and the strength of agglomeration is weakened, which results in low productivity and bad quality. In this paper, the process of pelletization of nickel laterite was developed, and some parameters to strengthen the pelletization of nickel laterite have been optimized. The results show that the compressive strength of fired nickel laterite pellet can reach over 2000 Newton per pellet while firing at the temperature of 1220 °C~1250 °C in 12 min. The product pellet can be used as high-quality burden for blast furnace to manufacture ferronickel.IntroductionIn recent years, the global stainless steel market was developed exuberantly, which greatly promoted the needs of the basic raw material of stainless steel smelting - metal nickel. Currently nickel sulfide ores are only 40% of global nickel reserves, but offer 60% of all the nickel production. However, with the deficit of resources, the nickel sulfide ore (high grade ore) is depleting, so there is an increasing focus on the utilization of low-grade nickel laterite. Recent research has focused on the wet treatment process to utilize nickel laterite, and less on the use of other technologies [1-8]. The economical and efficient technology relies on the reduction of nickel oxide and part of the iron oxide metal by agglomeration and smelting in blast furnace in China. Some domestic steel companies have adopted this process [9, 10]. Unfortunately a large fraction of fines is generated during the pre-treatment stages and the strength of agglomeration is weakened, which results in low productivity and bad quality of fired pellets. In this study, the process of pelletization of nickel laterite was developed firstly, and some parameters to strengthen the pelletization of nickel laterite have been optimized, and the product pellet can be used to produce stainless steel and ferronickel alloy by blast furnace."

Jan 1, 2011

By F. Tailoka

Microporous membranes have been used to create a very fine dispersion of bubbles which greatly enhances the mass transfer of electroactive species to the electrode. Using this system, it has been shown that it is possible to electrowin copper as a coherent planar deposit, at high current densities, from copper chloride solutions.

Jan 1, 1990

By Rolando Campos

The CODELCO-CHILE Teniente Converter Technology, is presently being applied in four Chilean smelters (Caletones, Chuquicamata, Potrerillos and ENAMI-Ventanas). A Teniente Converter is due to be used at ENAMI-Hernan Videla Lira (Paipote) smelter in the near future. Also, a Teniente Converter is to be installed as part of a retrofit project for Nkana smelter of Zambia Consolidated Copper Mines Ltd. (ZCCM). The charge to be treated through this smelter will consist of a blend of concentrate arisings from the various concentrators within the ZCCM group. The present status on the application of the Teniente Converter Technology at Caletones smelter as well as its projected performance when used at Nkana smelter, are presented in this paper. The design operational basis, autogenous smelting throughputs, concentrate to matte ratios and benefits due to the use of technical oxygen, are presented and analysed.

Jan 1, 1992

By I. Gaballah

The electrochemical behavior of a chalcopyrite concentrate having a high pyrite content was studied in HC1 by potentiodynamic, potentiostatic and galvanostatic experiments using a cell having separate anodic and cathodic compartments. Anodic oxidation of chalcopyrite particles was realized both by their contact with the cunent feeder and by reaction with ferric and cupric ions. An increase of current leads to a more selective dissolution of chalcopyrite. Surface passivation was observed after an electrolysis time related to the cell current. Cathodic reduction of chalcopyrite concentrate seems to be more promising. Almost complete conversion of chalcopyrite to a copper sulfide (Cui.8.S) is observed, whereas no reaction of the pyrite was detected. This confirms the possible selective dissolution of copper from the chalcopyrite concentrate. Copper sulfide obtained by cathodic reduction was leached using a cupric chloride solution.

Jan 1, 1994

By T. C. -M. Cheng

Iron removal and disposal in zinc plants has imposed a major environmental challenge to the industry. Among the existing options of precipitating iron as jarosite, goethite, and hematite, the Hematite Process seems to be the best candidate for the future development of a waste-free technology, because of its potential of producing saleable iron oxide residues for feed in iron-steel making industry. Unfortunately, under the current practice of the Hematite Process, it is not possible to produce iron residues clean enough to meet the specifications of the said industry. In this paper, the practice of industrial hematite precipitation and the relevant technical literature are reviewed with the objective to identify the critical processing parameters which are responsible for the contamination of hematite, particularly with sulfur and zinc. The analysis is conducted from a crystallization theory standpoint with emphasis given to the role of supersaturation with respect to the cleanliness of hematite precipitates.

Jan 1, 1997

By Ying Mao, Zhancheng Guo, Long Ma, Huiqing Tang

"A new 2D computational fluid dynamic (CFD) model was developed for the gaseous reduction of iron ore fines in an innovative reactor-multilayer moving-fluidized bed. The solution of the proposed model was performed by integration of FLUENT and PHOENICS. Numerical results of cold state were compared with the experimental data and the agreement between them was good. A hot case-gaseous reduction of iron ore fines using syngas with this reactor was simulated using the present CFD mode. Results indicate that under the given simulation conditions, total pressure drop is 90 Pa less than that under cold state though the gas supply rate is increased about 4m3 under hot state. Gas temperature decreases from 1073 K at the bottom to 500 K at the top, Utilization efficiency of the gas reduction potential is about 27 %. For ore fines reduction, the final reduction fraction could reach 0. 70 and solid temperature 900 K.IntroductionWith the development of coal gasification technology, various coals could be converted to Syngas with air or steam. Therefore gaseous reduction of iron ore fmes becomes an acceptable alternative process for iron making besides blast furnace route[!] and moreover it still has some advantages in processing low grade iron ore fines[2]. Gaseous reduction using fluidized bed technologies is the most competitive in all direct reduction iron-making processes up to now. It has the advantage that ore fines can be directly charged to the process without prior treatment while its disadvantages are particle agglomeration and high gas/solid ratio[3]. To avoid these advantages, a new reactor, multilayer moving-fluidized bed reactor has been developed for carrying out the gaseous reduction. Hydrodynamic behaviors of gas and fines in the reactor were studied and the results were satisfying[4]. However, due to its unique structure of the multilayer moving-fluidized bed and unique gas-solid flow pattern, models of multiphase flow as IPSA, DPM and Eulerian Model could not give a satisfying solution. The current paper is developed a new CFD model and a new solution approach for simulation of the reactive gas-solid flow in the multilayer moving-fluidized bed for its optimization, design improvement and future scale-up."

Jan 1, 2013

By Richard S. Kunter

Artech Recovery Systems, Inc has developed a low pressure and temperature? leach process called the "Cashman Process" to extract metals from arsenical flue dusts and residues and fix the arsenic in an environmentally stable form as ferric arsenate (scorodite). The process was pilot tested at Hazen Research in an integrated plant including continuous recycle from August 1989 to October 1989 during which several tons of flue dust were processed. Based on this pilot program, the process was deemed technically feasible and produced commercially salable products. Residues from this pilot program were subjected to a long-term stability test jointly designed by PTI environmental services and the USEPA. The process, its versatility, and the nature of the products is discussed in some detail.

Jan 1, 1992

By Liu Wei-feng

Base on the thermodynamic calculation of vapor pressure of lead, antimony and arsenic at high temperature, the possibility of separating lead, antimony and arsenic in different temperature was analyzed ,and the practice of producing qualified antimony white from lead-antimony alloy by direct blowing was introduced in detail in this paper. The blast furnace reduction smelting was brief introduced firstly, and then alkaline refining was applied to removing arsenic from lead-antimony alloy that contains As1%,Sb39%,Pb58%,the arsenic in the treated lead-antimony alloy could decrease to 0.009% by that method. The antimony white containing Sb2O3 99.5% could be produced by air blowing in the special furnace at 650? from the treated lead-antimony alloy. And the electrolytic lead could be achieved by electrolysis from the lead-rich alloy which contained 83% lead.With high-grade product being obtained the process was shortened. The technology has been applied successfully many years in Guangxi, China.

Jan 1, 2009

By William Petrul

Image analysis studies were performed on mill products from laboratory flotation tests of the Zn-Pb ore from the Faro deposit in Yukon, Canada, to determine mineral liberations at specific grinds and to predict recoveries at optimum flotation conditions. The minimum and optimum grinds for liberating sphalerite and galena were predicted from size analysis data for the minerals in large ore pieces, and determined by image analysis studies of the mill products. The determined optimum grinds are about 2 Tyler mesh sizes larger than predicted because sane of the fine grained sphalerite and galena occurs in interstices between coarser grained pyrite and is liberated when the pyrite grains are broken apart. Materials balance calculations were performed on the analyzed values for the liberated and unliberated sphalerite and galenaa to determine their distributions in the mill products. The laboratory flotation tests recovered 74% of the sphalerite and 83% of the galena in Zn and Pb concentrates respectively. The mineral evaluation study indicates that the optimum recovery for sphalerite and galena are 85 and 83% respectively. The company is currently recovering 80% 'of the sphalerite and 82% of the galena.

Jan 1, 1989

By Xu Weimin

The existing copper electrorefining tankhouse of Jinchuan Nonferrous Metals Complex (JNC) was commissioned in 1986 for refining blister copper anodes. Blister copper is produced by reverberating chalcocite separated from converter high grade nickel-copper matter by means of flotation. Special chemical analysis of the anodes shows, a composition of 93.02 - 95.72 % copper, 3.0 - 4.96 % nickel and 0.5 - 1.23 % sulfur. The wide range of composition makes the electrorefining process fairly different from others throughout the world. The initial nickel content of 20 ppm and sulfur 40 ppm or more in copper cathodes are reduced to 8.5 ppm and 11 ppm respectively. Since 1986 the tankhouse has undergone significant evolutionary modifications and implementations to ameliorate cathodes quality desirably. The important fact is that the N-additive was utilized through many studies and pilot and field trials successfully. While our primary purpose is to improve chemical quality of the cathodes, tankhouse capacity is increased considerably and the process is perfected satisfactorily. The tankhouse is described with special emphasis on JINCHUAN PROCESS. The upgrading of our product by the utilization of the N-additive is highlighted. The other aspects of the tankhouse including spent electrolyte treatment and by product nickel sulfate manufacturing are briefed as well. Key words: JINCHUAN PROCESS, anode, cathode, electrolyte, electrorefining, N-additive.

Jan 1, 1993

By Michael Sheedy

Recoflo® ion exchange technology utilizes fine mesh resin beads, a fully packed resin bed, and counter-current regeneration. These unique features help to improve exchange kinetics, reduce regenerant consumption, and increase the concentration of strip solutions. Commercially, Recoflo technology has been extensively used in the following areas: the separation of strong mineral acids from dissolved metal salts, the purification, removal and recycle of dissolved metals in the surface finishing industries, and the production of high purity water. In the mining and metallurgical industries Recoflo ion exchange systems have been installed to treat a copper refinery bleed stream at Falconbridge's Kidd Creek plant and to treat a nickel and cobalt bearing ammonium sulfate effluent stream at another primary metal producer's facility. In the first application an APU® Recoflo system is used to separate the sulfuric acid at 200g/L from the dissolved copper and nickel sulfate salts at 80 g/L. The absorbed sulfuric acid is recovered from the resin by elution with water and is then returned to the refinery electrolyte circuit. In the second application a chelating ion exchange resin is used to remove nickel and cobalt at 0.01 - 3.0 g/L from process streams containing 120 - 240 g/L ammonium sulfate. This Recoflo system has been designed to reduce the nickel and cobalt levels to 0.001 - 0.002 g/L while recovering cobalt and nickel at concentrations up to 30 g/L and 15 g/L respectively. Case studies for both these metallurgical applications and other Recoflo processes are presented in this paper.

Jan 1, 1998

By T. T. Chen

Raw anode slimes consisting primarily of PbSO4, AgCuSe, Cu3Se2, Cu2-x Se, Cu2O, CuSO4.5H2O, Sn arsenate and Sb-Bi-As oxide are batch-leached with electrolyte-O2 to dissolve Cu. During this process, Cu2O and CuSO4.5H2O are solubilized and the Cu in the selenides is leached with the formation of Ag2Se and Se. A small amount of Cu remains in the Ag2Se, Sn arsenate and Sb-Bi-As oxide. The decopperized slimes are repulped in Na2CO3 solution to convert most of the PbSO4 to NaPb2(CO3)2(OH). The Sn arsenate and Sb-Bi-As oxide partly react, but the Ag2Se is not significantly affected by the Na2CO3 solution. The NaPb2(CO3)2(OH) intermediate phase is dissolved in acetic acid to leave a final product consisting of Ag2Se, Se, Sn arsenate and Sb-Bi-As oxide, together with small amounts of PbSO4, NaPb2(CO3)2(OH) and various gangue constituents.

Jan 1, 1993

By M. Waladan

The top submerged lancing Sirosmelt system has been developed through laborator.y scale testwork and pilot plant trials for recovery of zinc from ISF slag. The effects of the process variables of gas injection rate, method of coal feeding, and temperature on zinc fuming rates were studied in the laboratory. It was found that the rate of zinc elimination was dependent on all of these variabl.es. The rate of zinc removal from slag was independent of zinc content of slag down to approximately 1.5% Zn, below which the rate was proportional to zinc content in slag. Pilot plant trials were carried out to evaluate a proposed process and results followed predictions from the laboratory scale tests. A comparison of the proposed process with conventional slag fuming operations is made and it is shown that the process has a number of advantages which have a significant impact on the economics of zinc slag fuming.

Jan 1, 1990

By B. Mishra

Several reactive metal purification processes using molten salts generate effluent from which significant quantities of metal can be recovered prior to discardinglrecycling the salt. A Salt-scrub [SS] process has been applied where the reactive metals are recovered as a metal-gallium alloy by calciothermic reduction of the metal compounds. The SS alloy compositions were produced by mixing, pressing and sintering the metal-powders. Measurement of metal recovery has been studied for cerium, silver, tin and lead. The process has been optimized for variables such as the metal quantity per kg of effluent salt, amount of excess calcium over stoichiometry, stirring rate and time and holding time at reduction temperature. Over ninety-seven percent metal recovery has been obtained under optimized conditions. The development of an alloy for efficient Salt Scrub processing reduces a major contaminated waste disposal problem as well as recovering the valuable reactive metal. Surrogate metals have been used in this work to study the behavior of plutonium.

Jan 1, 1994

By F. D. S. Marquis

An investigation of the mechanisms of formation of two types of porosity-primary and secondary-their characterization, evolution during processing, and effects on the mechanical behavior (fracture, fatigue, and failure) of 7X50 and 2X24 alloys has been conducted. The mechanisms of formation of three forms of primary or cast porosity were investigated, and each form was characterized: (a) macroscopic shrinkage porosity-MSP); (b) microscopic interdendritic porosity (MIP); and (c) hydrogen gas porosity (HGP) or primary hydrogen porosity (PHP). The mechanisms of formation of four forms of secondary or thermal/thermomechanical porosity were investigated, and each form of porosity was characterized: (a) high temperature oxidation (HTO). internal hydrogen precipitation (IHP), or secondary hydrogen precipitation (SHP); (b) preheating blistering porosity (PBP); (c) eutectic melting porosity (EMP);and, (d) dissolution micro void formation (DMF). The evolution and interactions of the primary and secondary types of porosity (w.ith special emphasis on PHP and SHP) during industrial and laboratory processing and their effects on the fracture and failure behavior of both types of alloys (with special focus on fatigue crack initiation and propagation) were investigated.

Jan 1, 1996

By J. M. Skeaff

As much as 100% of the gold and 67% of the silver in a sulphur-bearing hydrometallurgical leach residue have been transferred to copper metal at copper smelting temperatures by dissolving the partially calcined residue in an iron-bearing slag maintained in equilibrium with the liquid copper metal and matte phases. The precious metals can then be recovered by conventional refining techniques. Copper can be recycled at least four times without any detrimental effects on gold and silver transfers and recoveries. Apparent copper recovery in the .process can be over 100% because of the copper content of the residue. Based on slag analys.es, the overal1 recovery of gold in the copper metal and matte phases varies from 94% to 100% under all conditions investigated. On the? same basis, silver recovery varies .from 9S% ?to 99% under optimum conditions, but is only 4S% to 73% under other, less attractive conditions. Unaccounted for silver losses of' about 30% make it difficult to determine the major factors affecting ?silver transfer and recovery. A method for implementing the technology on a commercial scale at a Canadian copper/zinc smelter has been proposed. A preliminary economic assessment and comparison of the proposed pyrometallurgical process with conventional cyanidation indicates that either process is economically attractive for recovering gold and silver from leach residues. Although the capital costs are higher, the pyrometallurgical process is simpler, has higher recoveries, lower operating costs and no .potential environmental problems related to cyanide disposal.

Jan 1, 1989

By Y. Ono

In lightweight metal processing such as aluminum (AI) and magnesium (Mg), metal cleanliness is a crucial process parameter for refining, part manufacturing and recycling in order to obtain high quality parts and products. In this paper, techniques for cleanliness evaluation of molten AI and Mg using ultrasonic probes with clad steel buffer rods having high signal-to-noise ratio (SNR) are presented. Due to the high SNR of the ultrasonic probes used, backscattered ultrasonic signals from inclusions, which may be oxide films and/or particles, in molten Mg and those from silicon carbide particles, having an average size of 50f.Ull, added in molten AI are successfully detected with reflection configurations of pulse-echo and/or pitch-catch modes at an ultrasonic frequency of 10 MHz. In addition, relative cleanliness evaluation of molten Al and Mg is demonstrated. In order to establish the procedure and to investigate the optimum system configurations for cleanliness evaluation of molten metals, particle flow simulation system using water and polyvinyl chloride (PVC) particles has been constructed. Counting the number and measuring the size distribution of the PVC particles, having an average diameter of 128um, suspended in water with the PVC volume concentrations of 5ppm and 10ppm are performed with ultrasonic pitch-catch mode. The counted numbers of particles by the presented method and system have good agreement with the calculated results with a count error of less than 10% or two counts. Based on the results obtained with water simulation experiments, the prototype system for cleanliness evaluation of molten Mg by counting and sizing inclusions has been developed. Keywords: Ultrasound, Clad buffer rod, Molten metal, Aluminum, Magnesium, Inclusion detection, Cleanliness measurement, Counting, Sizing

Jan 1, 2003

By Ronald Erdmann

Today the BOF filter dusts and sludges are mainly dumped due to their zinc contents. By typically ranging from 2 to 5 % they prevent the filter dusts and sludges from beeing recycled via the blast furnace route. Based on the different discharge kinetics of Iron and zinc during the main blowing period In a bottom stirred BOF a simple and efficient system for recovery allow zinc fractions has been developed. The obtained material Is suitable for recycling without nsc of shell formation In the blast furnace. Different subsequent development steps have been performed. By starling with a very simple lime dependent model the sludge from the BOF off gas cleaning system was collected in two different sludge channel systems. This model based an the fact that most of the scrap based zinc Is discharged from the melt within the first eight to ten minutes of the BOF process. To Improve the system a spectroscope zinc sensor was Installed at the hot section of the off gas cleaning system to get more reliable informations on the actual zinc concentation of the BOF dust. By use of the system up to 50 % of the BOF sludge can be recycled.

Jan 1, 1995

By Sne?ana Devi

Mineralogy is a significant scientific discipline, essential in establishing the nature and the character of raw materials, regardless of whether they are monomineral or polymineral. Mineralogical characterization is very important, because its results give valuable information on features and nature of examined materials. Information's on mineralogical nature of mineral raw materials influence directly the quality assessment of a raw material, and thus the possibility of its use. The possibility of use of mineralogy in different industrial branches confirms constant activity of this scientific discipline. By use of methods within mineralogical analysis (optical microscopy, x-ray diffraction and others) data on mineral raw materials can be obtained as support in mineral raw materials quality assessment. Short description of results of mineralogical analysis of some mineral materials (granodiorite, dolomites, clay, refractory materials, slags and casting powders) in this paper shows the importance of its support to quality assessment and determine the possibilities of their use.

Jan 1, 2009

By David T. Bunney

In .December of 1987, International Mill Service, Inc. signed an exclusive licensing agreement with Tetronics Research & Development Co. Limited of Faringdon, Oxfordshire., England to commercialize plasma technology which had been demonstrated in an EAF dust processing application. The intent of the process is to reduce and volatize the zinc, lead and cadmium oxides inherent in EAF dust and collect these elements as metals in an ISP (Imperial Smelting Process) zinc splash condenser, and to render the resultant slag an inert, non-hazardous material. With these objectives in mind, IMS started commissioning facilities in 1989 at Florida Steel in Jackson, Tennessee and Nucor-Yamato Steel in Armorel, Arkansas. This paper will address the commercial development and progress of the technology at these two installations. Process Description In the EAF steelmaking process typically the off gas stream is cleaned by some form of baghouse. The particulate collected is known as Electric Arc Furnace dust and has been designated by the U.S. EPA as hazardous waste number K061, once it leaves the collection system. This designation was given to the material due to the high toxic concentrations of lead and cadmium (nickel and chromium for stainless EAF dusts) inherent in the dust. IMS' method of operation is to locate the facilities on the client mill's property adjacent to the baghouse. The dust is transported directly to IMS via a closed conveyance system. This method enables the technology to be an additional processing step in the steelmaking process. Once the dust has been transported to the IMS facility, it is fed, metered and mixed mechanically in the feed conveyance system with a carbon reductant (typically coke breeze). The carbon reductant is approximately 10% of the dust feed rate. This mixture passes through the feed system and enters the furnace

Jan 1, 1992