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By Mitsutaka Hino

The contents of gangue minerals, such as Al2O3. P2O5, crystalline water and so forth in the iron ore imported to Japan tend to increase year by year. Though the increments of such gangue contents arc approximately 0.1-0.2 mass%, some problems for the blast furnace operation in ironmaking process have already been reported, In order to clarify the mechanism of harmful effect caused by the small increment of gangue minerals, mainly Al2O3. on the blast furnace operation, the dripping behavior of Fe,O-CaO-SiO2-Al2O3-MgO slag from the iron funnel, which simulated the micro-porosity in sinter ore, has been observed with the wide range of basicity, Al2O3, Fe2O and MgO contents. The effect of MgO on the dripping behavior of slag has been summarized in this paper. It was found that the addition of 2mass% MgO resulted in large increase of hold-up on the most of the conditions. When Fe2O content was less than 20mass% and the basicity was lower than 0.8, MgO lowered the hold-up even if the slag contained 10mass% Ah03. Every slag hold-up showed the minimum at the basicity of less than unity on the conditions of constant Fe2O and Al2O3 contents, This trend became remarkable when the slag contained 2 mass% MgO.

Jan 1, 2003

By Florian Aurelian, Mihai Popescu

"It will be tested four types of “geochemical barriers”. All those mixtures were contacted with mine waters containing uranium, radium and heavy metals. The loading capacity was determined. The optimum mixture was determined and its efficiency was tested within an uranium areal, where the activity was stopped. It was determined the possibility to recover the radioactive elements and the heavy metals from the investigated barriers.IntroductionThe paper presents the results concerning the performances of some “geochemical barriers” used for the decontamination of mine waters from uranium mining sites, which were tested in lab and in situ.ExperimentalThe research activity was carried out in lab and on the site.In the lab a module was constructed in order to follow up the uptake capacity of the “permeable reactive geochemical barriers” used to remove the radiolelements from the contaminated waters originated from the uranium mining industry. The barriers, which were used, are made of cheap natural materials, which can be easily got (wood chips, peat coal, sawdust, iron span, steel and zeolitic tuff). The following types of barriers were tested:•, 1st barrier: peat coal, sawdust, zeolite on weight ratio of 1/1/1;•, 2nd barrier: bentonite, sand, wood chips, peat coal on weight ratio of 1/1/1/1;•, 3rd barrier: iron span, steel, sawdust, peat coal on weight ratio of 2/1/1;•, 4th barrier: iron span, steel, sand, firry wood chips on weight ratio of 1/1/1.Lab researches concerning the uranium uptake capacity of the above described “reactive barriers” pointed out that the 3rd mixture (iron span, steel, sawdust, peat coal on a ratio of 2/1/1) didn’t reach the maximum uranium uptake capacity not even after eleven contact stages (the uptake capacity being of 70.6 mg U/ kg of mixture) and the mixture of peat coal, sawdust and zeolite has an uranium uptake capacity of 26.6 mg U/kg of mixture and becomes saturated after four contact stages.Each one of the components involved in physical-chemical processes of sorption, reduction and precipitation, will determine the diminution of uranium and other metals contents upstream the permeable reactive barrier."

Jan 1, 2008

By Elias Rigopoulos

In the present study the reductive behavior of dust from the rotary kilns (RK), in ferronickel production from nickeliferous Greek laterites, is investigated. The study concerns dust of various origins (washing towers, electrostatic filters, polycyclones) and pellets made from the dust. Reducibility was studied in the temperature range of 700 °C to 850 °C in a laboratory tube furnace. Experimental results showed that reduction degree increases with temperature up to about 800 °C. The rate of reduction is great during the first minutes, giving a reduction degree R% equal to about 25%, in only a few minutes. After this, the rate is decreasing until it diminishes to zero after about 10-20 minutes of reaction. Maximum reduction degree achieved is 26 to 28%. Rates and reduction degrees at various temperatures are higher for the dust samples than those of the respective pellet samples. Keywords: Ferronickel, metallurgy, laterites, pellets, reduction

Jan 1, 2004

By Sasa Djokic

In developed countries, the difference between demanded and produced quantities of non-ferrous and rare metals are compensated by secondary raw materials recycling and reprocessing of by-products from both ferrous and non-ferrous extractive metallurgy. Utilization of non-ferrous and rare metals from the metallic secondary raw materials is very significant, both for recovery of the metal value and contribution to the environment protection. Similar to all non-developed countries, the extractive metallurgy in Serbia was based on available natural resources and not so strict environment protection regulations, which was either insufficient or completely absent. Today, Serbia is at the beginning of development of efficient and economical technical and technological solutions in order to ?ecologize? technogenic systems by waste materials, secondary raw materials and degraded soils regeneration (by recycling and revitalization). Several metallurgical technogenic systems in Serbia, together with secondary raw materials classification according to their potentiality for metal extraction by using the existing technologies and expected economical and ecological effects of recycling, are discussed in this paper.

Jan 1, 2005

Lime-enhanced carbothermic reduction may provide an alternative process for treating low grade chalcopyrite concentrates. To date, most research on lime-enhanced reduction has been on pure, synthetic sulfides. In this study, preliminary experiments were carried out on natural chalcopyrite using a thermal analysis system to assess the rate and extent of reaction at several temperatures and identify the major solid and gaseous reaction products. Calculations were performed to establish the thermodynamic limits of the reactions in the temperature range of interest in order to identify the potential conditions for processing chalcopyrite concentrate. The study found that finely ground chalcopyrite can be reduced carbothermically in the presence of lime at moderate temperatures and in a reasonable time to form metallic copper, with the sulphur reporting virtually entirely to calcium sulfide. At temperatures below about 750?770ºC calcium ferrite is the stable form of iron whereas at higher temperatures metallic iron is stable. Further work is required to demonstrate the reaction on a scale to obtain sufficient sample for evaluation of subsequent processing steps to remove the gangue material and iron products from the copper.

Jan 1, 2009

By Denise Crocce Romano Espinosa

The recycling of waste of electric and electronic equipment (WEEE) is one of the main modern challenges. Among the variety of WEEE, batteries can be set apart due to their composition and their growing demand along with portable devices. The objective of this work is to characterize the thermal behavior of a sample of mixed types of batteries using a thermobalance (TGA). The results of tests showed that Cd evaporated up to 800ºC, Zn evaporation occurred mainly above 900ºC and manganese oxides were pre-reduced to MnO at temperatures above 900ºC.

Jan 1, 2009

By Gabriella Tranell

In the manganese ferroalloys industry, there is increasing focus on the performance of different carbonaceous materials within the smelting processes. With a developing scarcity of traditional raw materials, new carbon sources are being identified for potential use in the processes. For this purpose, it is important to be able to predict the suitability of different materials in the process. Hence, the effects of both the physical and chemical properties of the carbon material on the reduction kinetics of manganese and silicon from slag to metal, have been investigated using an advanced sessile drop technique. Using this technique, the reaction patterns of SiO2-MnO containing slag droplets in contact with various solid carbon materials (graphites with different properties as well as cokes and charcoals) at 1400 to 1600\\176;C were studied in-situ. In addition, slag and metal reaction products from kinetic experimental series were analysed. From these results, differences in reactivity between various carbon materials and slags were demonstrated and explained. Mechanisms for both manganese and silicon reduction were proposed.

Jan 1, 2006

By David A. Neudorf

Known resources of nickel laterites considerably exceed nickel sulfide resources and there is a growing consensus that most new nickel production will be sourced from laterites. The development of nickel laterite projects is very capital intensive due to inherently low grades, inability to concentrate ore prior to processing, complex processing technology and typically large infrastructure requirements. This has resulted in most recently proposed projects being "mega-projects," to achieve economics of scale. However, this may result in unacceptable project risk in many cases. Furthermore, many known laterite resources are not large enough to support a mega-project. This paper describes an alternative model for nickel laterite project development that allows, smaller scale and reduces capital exposure. The requirements of this model in terms of process technology, infrastructure and commercial innovation are described. Keywords: Nickel, Laterite, Project, Economics

Jan 1, 2004

By Adam Powell, Salvador Barriga, Matthew Earlam

"The inert anode is a key enabling technology for dramatic energy and emissions reduction in extractive metallurgy. In molten salts, the materials challenge is nearly insurmountable: the anode must conduct electrons at high temperature in a pure oxygen and molten salt environment. A solid electrolyte, e.g. zirconia, between the salt and anode removes the molten salt stability constraint, and can act as a container for a liquid metal anode. This can be liquid silver for oxygen-generating inert anodes, or several metals for natural gas-fueled anodes; it is possible to switch between these modes. The solid electrolyte brings several other benefits: it eliminates molten salt contamination of the anode gas, creates a reducing environment enabling low-cost steel vessels, increases current efficiency, and eliminates carbon contamination of the product. New developments presented here, including current collector and low-cost anode designs, amplify these benefits for producing aluminum, magnesium, rare-earths, and other metals.IntroductionReactive metals such as magnesium, aluminum and rare-earths play increasing roles in efficient transportation and clean energy. In response to new fuel economy standards, automotive OEMs are planning large increases in use of aluminum and magnesium to reduce vehicle weight. Rareearth permanent magnet motors and generators exhibit better power-to-weight and efficiency than induction motors and other designs, making this today's primary motor technology for hybrid and electric vehicles, and for wind turbines. Nickel metal hydride (NiMH) batteries with lanthanum are dominant in hybrids. In 2011, transportation comprised 28.6 out of 103.1 EJ of US energy consumption [1] and 1,845 out of 5,471 million metric tonnes (MMT = 109 kg) CO2e of US greenhouse gas (GHG) emissions [1], creating big targets for economy-wide reductions.Unfortunately processes for making reactive metals for these applications are very inefficient and heavily-polluting. In primary aluminum production, Hall-Heroult cell electricity use [2] is more than double the reaction enthalpy due to heat losses through frozen cryolite side-walls and anode gases, graphite anode plants add significant energy use and GHG emissions [2] (see Table 1). Magnesium is even worse: silicothermic reduction by the Pidgeon process in China produces about 85% of the world's magnesium using coal or coke gas [3]. Chloride electrolysis begins with high-purity MgO and requires carbochlorination or hydrochlorination and costly chloride dehydration [4]—rendered unnecessary for aluminum by the Hall-Heroult cell. Production of neodymium and lanthanum with graphite anodes leads to inconsistent carbon content: small cells make 1 kg batches for analysis, sorting and sale by carbon content, with very high labor and analysis costs. And vertical electrodes give no incentive to reduce anode effect: some reports indicate that China's rare-earth metal industry emits more CF4 and C2F6—with global warming potential (GWP) 6500 and 9200 times CO2 respectively—than China's aluminum industry [5]."

Jan 1, 2014

By Jean-François Boulanger

The production of rare earth elements from ore usually consists of three steps; the separation of a concentrate of REE bearing minerals; the cracking of the REE minerals to liberate the REE into an aqueous solution and separation of REE into individual elements. This paper describes the results of laboratory tests conducted on a carbonate-rich REE ore containing bastnaesite and monazite. The tests cover the whole processing sequence of beneficiation, preparation of the REE solution using a caustic leach followed by acid leach to break monazite and bastnaesite and liberate REE into an aqueous solution and the partial separation of the REE using solvent extraction. Details on the product quality and process performances (recovery and impurities removal) are given for each studied step. The paper also discusses the economic advantage of separating the REE rather than producing a mixed REO product to be sold to a refinery for REE separation. A mini-pilot plant version of the process is currently planned.

By Jorge Alberto Soares Tenório, Flávia Paulucci Cianga Silvas, Denise Crocce Romano Espinosa, Ivo André Homrich Schneider, Erika Gusmão, Daniella Cardoso Buzzi, José Roberto de Oliveira

"This study evaluated the Salvinia sp action on metals biosorption in a synthetic sample of acid mine drainage (AMD) in order to determine the time and amount of metals uptake. Biosorptives tests were realized varying the contact time of 5, 20, 60 and 240 minutes. And keeping constant the follow parameters: pH (2.6), biomass concentration (1g.L-1), temperature (25°C) and agitation (175rpm). In order to quantify the metals concentration captured by biomass, the AMD samples will be analyzed by ICP. Biosorbent, Salvinia sp., will be characterized before and after the biosorptives tests through analysis of SEM and IR. The micrographs indicate the occurrence of micro-precipitation and changes in biomass physical structure. The infrared spectra indicate changes in functional groups present in the biomass before and after the biosorptives tests.IntroductionThe current emphasis on environmental sustainability leads the industry in general, to treat their waste. The human activities are increasing, highlighting the industrial and mining activities, and have promoted the contamination of soil, waterways and groundwater by metals (1). The waste must undergo treatment processes aimed at reducing pollution, and therefore, less aggression ecosystems.This means the importance of studies of economic and effective methods to eliminate these metals from wastewater generated. The bioindicators are good investments in this area. The aquatic weeds are plants that inhabit swamps up from truly aquatic environments. They have several morphological and physiological adaptations that enable them to colonize the various aquatic environments. They are used as bioindicators of water quality and have also been used in decontamination of aquatic environments, production of biomass for livestock feed, fertilizers, soil and fish tanks (2)."

Jan 1, 2012

By Robert L. Stephens

"It can be argued that one of the most important property of any material is cost, since this property detennines the applications for which a material can be considered. Despite growing demand and production for commodity metals such as copper, nickel, zinc, lead, and tin, the cost of these metals has been steadily decreasing in real terms. The only way that metal miners and producers can remain financially viable in the long term is by continuing to lower their cost curve through the implementation of new metals production technologies. This paper reviews technological developments in the production of copper, nickel, zinc, lead, and tin that have or threaten to redefine the cost curves for these metals.DisclaimerThe opinions expressed in this paper the author's, and are not necessarily those held by the author's employer, Cominco Ltd.IntroductionThis meeting will discuss many novel technologies and processes for producing metals and materials with specific properties that will enhance the applications ranges for the material or will allow entirely new applications to be developed. However, in every real-world case, the cost of the new material or process is an important property that determines which applications the material or process can be used in. Other properties that are important depend on the applications.A recent press report (1) discussing the potential replacement of aluminum radiators with copper radiators in pickup trucks and sport utility vehicles provides an interesting example to reinforce the importance of cost in materials selection. In this case, the displacement of aluminum by copper is being considered because of the more favorable heat dissipation characteristics of copper. Heat dissipation has become more important due to the development of hotter-burning V-8 and V-6 engines. For this application, engineers also consider cost, weight, size, durability, and manufacturing process. The report stated that the development by the International Copper Association (ICA) of the ""CuproBraze"" manufacturing process for heat transfer products was an important development. This technology produces 845 radiators that weigh less, are more uniform in quality, and are potentially more compact. They are also expected to cost less in high production quantities than copper units produced in the past, last three to four times longer than soldered copper radiators, and the process also eliminates the use of lead solder from the manufacturing process."

Jan 1, 2000

By Lauri E. K. Holappa

Ferrochrome, as the central constituent in stainless steels is one of the most rapidly growing primary metallic products. In this contribution results of a comprehensive study on the reduction process of chromite ore to FeCr are presented including thermodynamic examination, experimental work on kinetics and mechanisms in solid state, and smelting reduction conditions as well as kinetic modelling of solid state reduction.

Jan 1, 1999

By Michael S. Moats, Scott C. Campin, J. Brent Hiskey

"Electrochemical techniques are a valuable means of analyzing the passivation of commercial copper anodes. Electrochemical impedance spectroscopy (EIS) provides information concerning transport and reaction phenomena occurring at an electrode surface. Commercial. copper anodes of varying compositions have been examined using EIS. Experiments were conducted in a flat cell with an electrolyte of 40 gil Cu2 + and 160 gil H2S04 maintained at 65 DC. Impedance spectra were obtained at the potentials characteristic of the open circuit voltage and passive region for each anode. The spectra of the passivating films exhibited a flattened resistive/capacitive loop at middle to high frequencies and an inductive loop at low frequencies. An equivalent· circuit utilizing an inductor-resistor series in parallel with the double layer capacitance and charge transfer resistance was adequate in modeling the impedance data. The influence of anodes impurities on the components of the equivalent circuit is discussed and correlated with a hi-layer passivation model.IntroductionPassivation of copper anodes during industrial electrorefining has received considerable attention in the past few decades. Great strides have been made in understanding the roles of anode impurities [1-25], electrolysis parameters [20,26], and electrolyte chemistries [20,26]. Even so, passivation still occurs even in the most modem of refineries. The exact cause of passivation is not fully understood. It is known that the anode surface becomes covered by a passivating film. This film has been proposed to be CuS04'&5H20, Cu20, or mixed oxides. The localized concentrations of Ft, Cu+, and Cu2+ ions determines which phase is more favorable. The presence of these ions is controlled by the reaction kinetics and diffusion of species through the slimes layer.Reaction kinetics between Cu, Cu +, and Cu2+ are based on the dissolution mechanism of copper. There exists four different models to describe the dissolution of pure copper. The classical model of Mattsson and Bockris [27] involves two single electron transfers with the cuprous-cupric reaction being the rate detennining step. More recently, Wong, Collier, and MacFarlane [28] used ac impedance to elucidate a more complex mechanism involving the affect of pH and anions. Their findings indicate that the formation of cuprous ions in solution, Cu(I)so~ is favored over Cu(1I) ions adsorbed to the electrode surface in the presence of sulfate and as pH increases from pH 1 to pH 5."

Jan 1, 1997

By Christopher Gammons

In developing countries throughout the world, gold ores are being processed by mercury amal-gamation, a technique long banned in the U.S. - unless a retort operation is used for mercury recovery - due to mercury toxicity and its effects on the environment. Amalgamation is a simple process that involves contacting a ground, slurried concentrate or ore with mercury in a slightly agitated vessel, usually for several hours, The amalgamated mercury is separated by gravity and then filtered through a fine cloth to collect the gold amalgam as a sponge, which is then fired to remove the final remnants of mercury and produce high quality gold. However, in Peru and other developing countries in South America and throughout the world, tailings are simply discarded into uncontrolled drainages and ponds and the sponge is fired in the open air. Clearly, in this case, environmental friendly and, to make matters worse, is typically conducted by family members of all ages without proper protection. Furthermore, the technique is inefficient, yielding approximately 50% gold recovery. For the past two years, faculty members from Montana Tech in Butte, MT, USA and the Universidad Nactonal del Altiplano in Puno, Peru have teamed to study the La Rinconada Mine Complex located in southern Peru approximately 100 kilometers north of Lake Titicaca and 25 kilometers west of Bolivia. The mining complex is over 5,000 meters above sea level and exists at the foot of a receding glacier in the Andes Mountains. A suite of soil and water samples collected in 2001 documented extensive Hg contamination in the Rinconada area [1]. The present paper summa¬rizes a follow-up investigation in July-2002, in which water samples were collected at numerous locations along the 200 km length of the Rio Ramis, from the Rinconada mine com¬plex to Lake Titicaca, In addition, we report new results of Hg analyses of fish from Lake Titi¬caca, The results of this study have relevance to safety and health concerns for the miners as well as people in downstream communities.

Jan 1, 2003

The cleaning of copper containing fayalite slag using a CuFe alloy was studied under an oxygen pressure ranging from 10-7 to 5 X 10-11 atm at 1200º c. The reduction of copper from fayalite slags by Cu-Fe alloys was found to be very effective. For example, at a P 02 of 10-7 atm, the copper content in the slag was reduced from 4.1 to 0.402 wt. percent after 90 min. of reaction time using a Cu- 5.27 wt. percent Fe alloy. The copper reduction rates were found to be independent of P02 in the gas phase when using Cu-Fe alloys which exhibit an iron activity of greater than 0.4. A mechanism for slag c1eaning is proposed based on the concept that the Cu-Fe alloy lowers the oxygen potential of the slag according to Eq.1 1, fol1owed by the reduction of cuprous oxide by wustite as shown in Eq.2. Here X represents element X in the alloy phase while (X) represents the element in the slag phase. The copper and iron transfer behaviour obtained in this study are explained by a ?Stepwise equilibrium model.

Jan 1, 1985

By Tiebao Yang

In high pressure die casting processes, a die plays a critical role in removing heat from the molten metal during the cavity filling and solidification stages. Proper control of die temperature is essential for producing superior quality components and yielding high production rates. This paper proposes a local temperature control scheme for die thermal management based on a computerized intelligent real-time monitoring and control system (IRMCS). In this scheme, cooling water lines are controlled by a pump and solenoid valves. A controller is designed according to the law of die temperature fluctuations. The results obtained from the experiments carried out on a laboratory die casting process simulator indicate that the controller can limit the local die insert temperatures in a given band. Hence, the desired thermal pattern of the die insert becomes achievable.

Jan 1, 2006

By Farhang Hedjazi

Anglo Asian Mining have recently installed an industrial-scale UF/RO plant to treat process liquors from the integrated heap leach/agitation leach/ resin-in-pulp gold ore treatment facilities at their Gedabek gold-copper mine in Azerbaijan. The UF/RO plant is designed to treat 60 m3/h of leach solution to produce discharge quality water. The RO concentrate, which contains elevated concentrations of copper, silver and cyanide, is sent to the company’s SART plant for the recovery of the metal values as a precipitated sulphide concentrate and the cyanide, which is recycled to leaching. The new water treatment plant improves the sustainability of the operations at Gedabek by enabling replacement of fresh water input with RO permeate and safe discharge of permeate to the environment, during periods of excess water balance. The paper includes pilot plant data and early results from the full-scale plant.

By Sharif Jahanshahi

Calcium ferrite slags are often associated with Professor Yazawa due to his pioneering work on the thermodynamics of this type of melts. Over the past years CSIRO has invested some effort in studying physico-chemical properties of such melts to fill in some gaps in our knowledge and explore opportunities for application of the understanding developed. These investigations cover thermodynamics, transport properties of calcium ferrite based slags, as well as the kinetics of reactions of such slags with refractories. The present paper provides an overview of some of these studies and highlights some of the interesting behavior of such melts, The oxidation state of copper and arsenic in calcium ferrite based slags are predominantly Cu+ and As3+, respectively, at oxygen potentials below 10-7 atm. The concentration of CU2+ in such slags becomes significant at oxygen potentials of greater than 10-7 atm at 1300 °C. The activities of CuO0.5 and AsO1.5 in calcium ferrite slags show strong deviations from the Raoultian Law, while that of CoO is very close to ideal behaviour with respect to pure solid CoO. Addition of SiO2 to calcium ferrite slags can have significant effects on the activities of FeO and Fe2O3 and hence the stability of magnetite phase. Transfer of oxygen in calcium ferrite slags is fast with diffusivity of 2x 103 cm2/s at 1350 °C and activation energy of 16 kcal/mol. Presence of solid phases, such as magnetite, has pronounced effect on the viscosity of calcium ferrite slags. The observed dependence on solid loading and shear rate indicates deviation from Newtonian behaviour. The interfacial tension between copper mattes and calcium ferrite slags is strongly dependent on the matte grade, with the determined values being much lower than the corresponding ones for interfacial tension between similar mattes and iron silicate slags. MgO, Cr2O3 and MgCr2O4 have low solubility in calcium ferrite slags and their solubility increases with increasing copper oxide content of the slag at 1300°C. The oxidation state of the slag has strong effects on phase transformation, dissolution rate and disintegration of refractories in calcium ferrite slags. Other key factors with major impact on slag-refractory interactions include viscosity and surface tension of slags as well as the contact angle between slag and refractory material,

Jan 1, 2003

By Zhao-feng Xie

A new process of recycling valuable metals containing in the slag of jamesonite smelting in the blast furnace was studied. In this process, the valuable metals such as Pb, Sb, Zn and In etc. were fumed and volatilized and enriched in the dust firstly and then the dust was leached by sulfuric acid. In the leaching procedure, Zn and In in the dust entered into the leaching solution and were separated from Pb and Sb which remained in the residue.The optimal operation conditions of the fuming procedure are as follows: the mass ratio of the blast furnace slag, coal powder and lime are 100:22:10 respectively and the fuming time are 1.5~2.5 h, the fuming temperature is not below 1200C and the volatilization rates of Pb, Sb, Zn and In are 95%, 92%, 86% and 75% respectively. The optimal conditions for the leaching procedure are also presented: the consumption of sulfuric acid is 1.15 times of the theoretical consumption, the ratio of liquid to solid is 4:1 and the leaching temperature, leaching -1time and stirring speed are 90, 1.5h and 300 r?min separately. The leaching rates of Zn and In are 98.5% and 95.2% respectively. The experimental results shows that the valuable metals in the dust can be recovered and separated effectively by this process and the?ir recovery efficiencies are as follows: Pb94%,Sb91%, Zn84% and In69%.

Jan 1, 2009