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By Zhou Shu-cai

"A method has been proposed for the pre-treatment of high phosphorus iron ore by carbothermic reduction assisted with microwave irradiation and magnetic separation on a laboratory scale. Chemical analysis of the reduced ore sample, the metal sample and the slag sample were conducted. Based on the above research, the influences of carbon addition, microwave power and microwave irradiation time on the recovery of Fe and dephosphorization were discussed. It indicated that the increase of microwave irradiation time and power had substantial effect on the recovery of Fe while the influence of carbon addition was not obvious and the highest iron recovery ratio reaches some 95.5% when the dephosphorization ratio was 37.68%. A high iron recovery ratio and a reasonable dephosphorization rate were incompatible under the conditions investigated in this study due to the reduced iron and because unreduced P-contained gangues were not efficiently separated. This method may provide a reference for the future utilisation of high-phosphorus iron ore.IntroductionWith the rapid growth of crude steel production in China, the source of iron ore tends to become increasingly strained and is facing the risks of raw material shortage for the iron and steel industry. In order to decrease the production cost, China has to focus on the utilization of its domestic low grade iron ores for the iron and steel plants [1-2]. China has a large deposit of high phosphorous iron ore with a reserve of 7.45 billion tons which is unused in any large scale [3]. Therefore, the development of a successful and economically viable technology for high phosphorus iron ore is of profound importance. To remove phosphorus from the high phosphorus iron ore, several mineral and metallurgical processes have been proposed, such as bio-leaching [4], roasting reduction plus melting separation [5], pre-reduction and screening methods combined with mechanical crushing or air jet milling[6] selective agglomeration plus reverse flotation [7]. However these processes are not cost effective or are time consuming. The traditional pyrometallurgical process( BF+ BOF) refuse this kind of ore mainly because that molten iron is saturated with carbon or high carbon content and thus all phosphor us in the burden goes to the molten iron[8]. Therefore, it is important to exploit the cheap and abundant high phosphorus iron ore as a resource in ironmaking. In recent years, the microwave was widely introduced as a heat resource for extractive metallurgy of iron ore or other minerals. For example, microwave assisted ore milling, microwave assisted carbothermic reduction of metal oxides and microwave assisted mineral leaching issues[9-10]"

Jan 1, 2014

By Patrick R. Taylor

A non-transferred arc thermal plasma assisted cyclone reactor has been designed, built and operated to evaluate its use in vitrification of wastes. Simulated waste (liquid, slurry or fine particulate) is injected near the plasma flame, where nearly instantaneous dehydration and calcination reactions happen. A non-transferred arc plasma torch was attached tangentially to the cyclone and is utilized as both an enthalpy source and to provide the gas velocities required to generate the cyclonic gas flow patterns. The closed top cyclone flow sends the solid particulates to the wall, where they are captured by a thin film of molten glass that is injected as a powder at a position lower in the reactor. The molten glass is then collected in a crucible. The feasibility of simulant injection directly into the flame zone and its effect on electrode lifetimes has been studied. Several candidate refractory systems have been evaluated for their suitability for extended use under the demanding conditions present in the cyclone reactor.

Jan 1, 2002

By Chaoying Ni, Dimitry Sediako, Prashant Karandikar, Sean Fudger

Neutron diffraction measurements were performed on steel encapsulated metal matrix composites (MMCs) in order to quantify bulk residual stresses. A coefficient of thermal expansion (CTE) mismatch induced residual compressive stress method is utilized as a means of improving the ductility of the MMCs and overall efficiency of several macro hybridized materials systems. Systems consisting of an A36, 304 stainless steel, or Nitronic® 50 stainless steel shell filled with an Al-SiC or Al-Al2O3 metal matrix composite are evaluated in this work. Upon cooling from processing temperatures residual strains are generated due to a CTE mismatch between each of the phases: steel, aluminum, and reinforcement. The analysis shows variation in the measured strain and stress results due to outer steel thickness, difference in CTE between materials, and relative position within the composite.

Mar 1, 2017

By Torma A. E.

Biotechnological processes are considered to be cost effective especially for situations where the recovery of metals from 'Very large volumes containing trace metal concentrations (less than 10 ppm) is concerned. Microorganisms, alive or dead, or their products can be highly efficient and selective biosorbents for metal concentration. It is important that the metal bound to the biosorbent can be stripped by suitable agent(s) and regenerated for repeated use. The stripped solution should be concentrated enough to be introduced into the common metal recovery circuit. The industrial acceptance of biosorption processes is dictated by increased competitive advantage over other processes. This paper reviews the pertinent literature?, regroups the information, and points out future possibilities for the mineral and metal processing industries.

Jan 1, 1992

By D. B. Dreisinger

The zinc pressure leach process developed by Sherritt Gordon, Ltd. permits the direct leaching of sulphide concentrates according to the overall reaction, ZnS +H,zS04 +402.+ZnS04+H20 +S0 The kinetics of the leach are affected by three rate controlling steps; ( l) oxygen mass transfer from the gas to the leach solution, (2) homogeneous oxidation of ferric ion to ferric ion by dissolved 011.ygen and (3) ferric ion leaching of zinc sulphide in the presence of a sulphur dispersing detergent (lignin sulphonic acid). Fundamental studies have been conducted to identify the factors that influence the kinetics of each individual rate controlling step. Oxygen mass transfer studies have been directed toward optimization of the agitator configuration for solids mixing and gas pumping from the atmosphere above the leach slurry. The rate of ferrous oxidation by molecular oxygen and the rate of zinc sulphide leaching by ferric ion have been studied over a wide range of temperature and solution compositions. The study of zinc sulphide leaching by ferric ion was supplemented by a series of interfacial tension measurements in the liquid sulphur - zinc sulphate solution system. The various kinetic studies have been summarized in terms of the importance of each rate to the performance of the process.

Jan 1, 1990

By Zhou Jun

Water-quenched samples were taken from a commercial flash furnace at three levels along its reaction shaft during operation at high feed rate. The samples were subjected to a series of analysis and observation. Such processes of the feed in reaction shaft as oxidation, desulfurization, melting, slag and matte formation and etc., variations of particle size along axial and radical direction of the shaft are investigated. The following smelting mechanism in reaction shaft named as “Multi-particle and multi-phase fusion model” is proposed: (1) Fragmentation and collision of concentrate particles take place simultaneously in reaction shaft with particle size growing up. Collision produces large-size “unit melt” which falls into the reaction layer in the settler bath. (2) In the settler reaction layer below the shaft, weak bath smelting reactions take place among the shaft products, producing final matte and slag which separate into two layers. (3) The processes in the shaft are all progressive along the whole height of the shaft. The predominant reaction in the shaft is oxidation, not reduction.

By Kymberley Worrell

The Cripple Creek and Victor Gold Mine was acquired by Newmont in August 2015. The high grade flotation mill project was commissioned in February 2014. The mill to date has been throughput limited due to mechanical and design issues. In order to create the most value from a throughput limited plant a campaign to provide timely ore characterization was undertaken. A diagnostic leach methodology was developed to determine gold associations by ore type. The resulting associations were then used to characterize feed blend; gold losses and optimize gold production. The diagnostic methodology is presented along with discussion on flotation implications.

By Naiyang Ma

Along with fast growth of EAF steelmaking, better ways of treating EAF dust have been continuously pursued for better environmental protection and better economic benefits. In this contribution, various ways of collecting EAF dust in EAF off-gas cleaning systems are reviewed, and generation of dust and concentration of zinc in the dust from various collecting devices are examined. Accordingly, recycling of EAF dust through source separation is discussed.

Mar 1, 2018

By Ross W. Smith

Microorganisms are increasingly finding use in mineral processing and hydrometallurgy both for the enhancement of mineral engineering operations and for the remediation of mineral industry wastes. Some of the applications, such as biologically assisted leaching of sulfide ores and biooxidation of refractory sulfide gold ores, are established commercial processes. Others, such as the use of organisms for the removal of heavy metal ions from dilute aqueous streams, are nearing commercial application. Other uses of microorganisms are potentially possible. These include use of microorganisms in leaching non-sulfide ores, the flocculation or flotation of minerals and remediation of toxic chemicals discharged from mineral engineering operations.

Jan 1, 1993

By George P. Demopoulos

In this paper the production and stability of crystalline scorodite (FeAsO4·2H2O) is discussed both on the basis of previously published work as well as recent work performed in our laboratory. The production of scorodite, especially from arsenic-rich and iron-deficient sulphate solutions offers a number of operational advantages such as high arsenic content, stoichiometriciron demand, and excellent dewatering characteristics. In addition to hydrothermal production of scorodite the work done over the last 10 years in our laboratory has determined that it is feasible to produce scorodite by step-wise lime neutralization at 90°C. The atmospheric scorodite possesses the same structural and solubility characteristics with the hydrothermally produced scorodite. Long term equilibration tests (up to 66 weeks) in the pH range 5 to 9 and temperatures from 22 °C to 75 °C revealed scorodite to undergo slow incongruent dissolutionyielding a highly metastable nano-sized 2-line ferrihydrite phase. The equilibrium arsenic concentration with this phase was 0.35, 0.96 and 5.87 mg/L at pH 5, 6, and 7 respectively at 22°C. In the presence of gypsum slightly lower concentrations were measured, this being more pronounced at pH>7. It was tentatively deduced that a Fe-Ca-AsO4 association (in the form of a phase resembling the mineral yukonite) contributes to the lowering of As concentration. Finally thermodynamic calculations determined that scorodite is stable in the presence of ferrihydriteunder oxic conditions up to pH 6.75 at 22 °C or higher pH at lower temperature and gypsum-saturated solutions. Keywords: Scorodite, Crystallization, Arsenic, Solubility, Stability, Precipitation, Disposal, Extraction, Processing, Metals, and Environment.

Jan 1, 2005

By Florian Kongoli

Converters have been playing an important role in the extraction and processing of metals ever since the first type of converter was invented about 100 years ago. Historically their operation has been mainly based on the experience of talented operators rather than on strict control and optimization technologies. However, in the new realities of unavoidable necessity to increase productivity and in the conditions of diversification of primary materials from various geographical areas, improving control and optimization techniques have become indispensable. In this paper a review of the authors? previous work in terms of improving control and optimization of converter operational practices related to magnetite content and precipitation, slag and metal blows, problematic and dangerous elements such as As, Sb etc. has been described by highlighting the advantages that the new control and optimization methods and tools bring to everyday converter practices. Several examples are given and future work is underlined

Jan 1, 2005

By N. J. Themelis

The basic chemical, thermal and transport principles that underlie sulfide smelting of. copper, nickel and lead are reviewed. Two basic types of modern smelting processes are distinguished?: flash-smelting, where the predominant reactions occur between oxygen-bearing gas and concentrate particles dispersed therein; and bath-smelting where the concentrate is enveloped and reacted in a turbulent bath of matte, slag and gas. The controlling heat and mass transfer phenomena are discussed, and appropriate correlations are proposed.

Jan 1, 1983

By Satu Strömberg

A single-particle laminar-flow technique was used to study oxidation of two nickel concentrates and a granulated nickel matte (43 wt% of Ni). Experimental conditions were: reaction gas from N2 to N2 + 75 vol% O2; gas preheating temperatures ranging from 500 to 1100°C. The major nickel-bearing minerals in the two concentrates were pentlandite and violarite, respectively. Chemical analysis of the particles was used to determine the oxidation degree of the materials, and optical and scanning electron microscopy were used to detect their morphology and mineralogy. Total desulfurization of the nickel concentrates was achieved under the most oxidizing conditions, while the sulfur removal from the nickel matte was not as efficient, especially with the coarse size fraction. Pentlandite-based concentrate was found to be less reactive than the violarite-based.

Jan 1, 1995

By H. Ikeda

The new Onahama N0.3 tankhouse was put into operation early in 1973. This new tankhouse, which has a capacity of 90,000 metric ton cathode per year, is distinct in many important respects from conventional tankhouses. The major objectives in design were to simplify the construction and ope- ration for reduction of the costs for labor, interest and depreciation and also to reduce the copper inventory in the tankhouse by the use of conti- nuously-cast anodes. As a result, the investment cost was decreased by approximately 30% and the inventory cost by approximately 600, while the production per unit area of the tankhouse was increased by 80 - 100% as compared with the existing conventional-type tankhouses at Onahama. By abolition of cell inspection and maximum mechanization of materials handling the labor cost was decreased by as much as 80%. On the other hand, the new system has some disadvantages, such as increase in anode scrap ratio and increased cost of anode casting. The No.3 tankhouse system is, however, still at its starting point, while conventional methods have been continuously improved over the past years of operation. It is expected that the innovational ideas behind this system will serve as bases for a more efficient electrolytic refining system in future.

Jan 1, 1976

By Deng Ma

In order to obtain the solubility of carbon in vanadium-bearing hot metal, graphite powder is used for the carburization experiments. The other kinds of carburizers, namely low nitrogen carburizer, anthracite and coke are used for carburization of vanadium-bearing hot metal weighing 500 g at temperature of 1450, 1500 and 1550 °C respectively. Carbon increments of low nitrogen carburizer, anthracite and coke fall in descending order. It was found by comprehensive analysis that anthracite is the most cost-effective carburizer among three carburizers. Magnitude of apparent rate constant of carburization reactions is 10−4s−1. It is found that the carburization rate increase with temperature.

Mar 1, 2018

By Shengfan Zhou, XUEWEN WANG, Fuhong Xie, Qi Ge, Bianfang Chen, Biao Liu, Mingyu Wang, Sheng Huang

To recover iron, titanium, vanadium and chromium from vanadium bearing titanomagnetite, a process of direct reduction has been proposed. After magnetic separation, a material containing titanium, vanadium and chromium was obtained. In this paper, a salt-roasting process was proposed to extract vanadium and chromium from the material containing titanium, vanadium and chromium. The effects of the several parameters that included roasting temperature, roasting time and the addition of sodium carbonate were investigated. Under the most suitable conditions including a roasting temperature of 900 °C, roasting time of 2 h and sodium carbonate addition of 33 wt%, the leaching of vanadium and chromium reached 91.2 and 68.4%, respectively. After leaching, the leach residue can be used as the raw material for extraction of titanium.

Mar 1, 2018

By J. R. Odekirk

The nature of mineral distributions and locking characteristics in mill products are important factors in understanding mill performance. Such data are obtained by microscopic point counting methods. Reduction 'of point-count data from volume to weight percentages, and reduction of data for each size fraction back to a head sample requires lengthy hand calculations. The use of computer processing for such data reduction results in obtaining information on a realistic time basis. An example of computer processed point-count data is presented.

Jan 1, 1981

By Jan Pan, Deqing Zhu, Xianlin Zhou, Yanhong Luo, Zixing Xue

"Magnetic roasting process, aiming at obtaining magnetite concentrate, is the principle method of exploiting siderite as a raw material in iron and steel industry. Study on preparing DRI from siderite through coal based reduction technology is sporadic. To make the process of how siderite is reduced to iron clear, roasted ore reduced from siderite by lignite under different time periods were analyzed. The results indicated that: at the temperature of 1050°C, siderite was rapidly decomposed into magnetite, and further reduced as Fe30r?FeO?Fe, the later step was slower than the previous one. A fracture of particles was found during the process of thermal decomposition and the reduction of newly formed magnetite. As the reduction proceeded, metallization rate of products increased, and the iron grain grew along with time.IntroductionWith the rapid development of economy, China demands more and more iron ores for the iron and steel industry. China has rich iron ore resources, but 97% of them are below 30% in iron grade, many are refractory and unutilized [1], therefore large quantities of imported iron ores are in a desperate need. China imported 686 million tons of iron ore in 2011 (data from the China Customs), accounting for nearly 60% of the total consumption. To guarantee the healthy development of iron and steel industry, domestic refractory iron ores have to be utilized both economically and environmentally."

Jan 1, 2013

By Jared Ball, Darren Snashall, Paul Telford, Pengfu Tan, Ben Hogg

"The foamed converter charges were up to 3 8 per month in Xstrata Copper Smelter at Mount Isa. The issue of high converter foamover frequency had remained unsolved for many decades in Mount Isa. A thermodynamic model of copper P-S converter and a viscosity model of converter slag have been developed to simulate the slag blow and copper blow, in order to understand the mechanism of converter foamover. The model predicts the chemistry and viscosity of slag during slag blow and copper blow. The effects of oxygen potential, charge of dirty reverts, slag carryover, under-blowing, over-blowing, and temperature on the foamover and viscosity of slag in copper blow have been discussed. A theory has been developed to understand the mechanism of converter foamover. The practical solutions have also been developed and implemented in Mount Isa Copper Smelter. Some improvements of the industrial operations have been presented. After a series of improvements, the number of foamed charges per month in the converter operations has been decreased significantly from 35 in Aug 2008 to only one per month in 2009/2010.1. IntroductionThe Copper Smelter in Mount Isa receives the concentrate containing about 25% copper and produces anode copper that contains about 99% copper. There are several stages in the process. The first stage carries out in the ISASMELT™ furnace. The ISASMELT™ process produces a molten copper matte containing about 60% copper. An iron-silica slag and a sulfur dioxidebearing off-gas are the by-products of the process. The slag is taken to the slag dams for cooling before it is recycled through the Mount Isa Copper Concentrator.The matte is sent to Peirce-Smith converters. The converters further remove iron and sulphur to produce blister copper which contains about 97% copper. The anode furnaces remove any remaining sulphur and oxygen to produce anode copper that is about 99. 7% pure. This is cast into anodes and sent to the Xstrata Copper Refinery in Townsville for final refining.In the copper pyrometallurgical industrials, slag foaming is an important phenomena which occurs when the gas bubbles have stability and not rupture. Foaming greatly increases the interfacial area between matte, slag and gas and is essential for the operation of high intensity smelting processes. However, foaming or foamover is undesirable in P-S converter since it can damage the equipment and injure the operators. Figure 1 shows that the whole process of a foamover development in a converter."

Jan 1, 2011

By Zhongming Ren

"A new process of near net shape continuous casting of metal pipe has been put out. The specialty of the process is that no inner core is used. The principle of the process has been presented, and the effect of several factors on the thickness of the pipe has been investigated experimentally and numerically. It is shown that the temperature and the level of the molten metal, cooling intensity of the mold, and the velocity of casting influenced the thickness of the pipe apparently. In order to improve evenness of the thickness of the pipe, the mold was dedicatedly designed, and special methods were taken. By this process, a metallic material like ""bamboo"" was fabricated.IntroductionMetal pipe is a widely used material. Up to now, many processes have been put out to produce the pipe. However, the processes are usually expensive and inefficient. For instance, the welding pipe, which is most widely used, is produced through continuous casting of slab, rolling of the slab into sheet, and welding, with several times of heating and processing. Continuous casting of pipe can not produce small diameter of pipe, which is mostly needed, due to the inner core. Even though. OCC process is novel in fabricating the pipe with small diameter, it is inefficient. In this paper, the no-inner core continuous casting of pipe was proposed. With this process, pipe with small diameter can be produced efficiently. The influence of several parameters on the thickness and evenness of piper wall. With this process, a ""bamboolike"" pipe was fabricated.ExperimentThe experimental apparatus is shown in Fig. I. It is composed of mold, furnace, melt level adjuster, and dummy pipe. In the process, the level of the melt was adjusted at a proper position, then the mold along with the dummy pipe was inserted into the melt in a certain depth. The melt in the mold began solidifying, forming a solid shell. After that, the dummy pipe was pulled upward in a certain speed, drawing the solid shell out of the mold. Thus, a pipe was continuously cast."

Jan 1, 2000