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By J. N. Hartley

Samples of ash from the May 18, 1980, eruption of Mt. St. Helens Were collected from several locations in eastern Washington and Montana. The optical microscope and the combined scanning electron microscope with energy dispersive x-ray microprobe were used to determine the composition and mineralogical characteristics of the samples. In addition, a quantitative image analyzer was used to examine the particle size distribution, and x-ray diffraction was used to identify major minerals. Both polished sections and ultra thin sections (less than 5 ~m in thickness) were prepared to study the mineralogical characteristics. The use of ultra thin sections provided access to microstructural detail. Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystal-line samples were dominated by plagioclase feldspar (andesine) and ortho-pyroxene (hypersthene) with smaller amounts of titaniferous magnetite and hornblende. Nearly all the samples contained from less than 1 to 3 wt% free crystalline silica (quartz, trydimite, or cristobalite).

Jan 1, 1981

By Wei Luo, Yuanbo Zhang, Zhixiong You, Zijian Su, Guanghui Li, Tao Jiang

"In this study, the appropriate sintering process parameters for low-grade ferromanganese ores were investigated. The results showed that, under the condition of natural basicity (R=0.03), the optimal parameters were obtained as follows: moisture of mixture 9 .1 %, coke powder 9 .9% and sintering negative pressure 7 KPa. And the corresponding yield, ISO tumbling index and utilization coefficient reached at 80.18%, 61.27% and 1.515t·m-2·h-1, respectively. Under the optimal parameters, the emission of harmful gases, such as S02 and NOx, were reduced evidently with 30% of coke powder replaced by biomass charcoal. Moreover, it was found that the basicity had obvious effects on the quality of the sinters when it changed between 0.03 and 2.4. The ISO tumbling index gradually decreased from 61.27% to 55.47% with the basicity increasing from 0.03 to 1.2, then, it began to increase after the basicity further increased to 2.4.IntroductionManganese is mainly consumed by steel and battery industries, particularly in the steel plants and ferroalloy units. The consumption of metal manganese in the ferroalloy industry accounts for 85%-90% of the total Mn [1-2]. Therefore, ensuring sufficient manganese alloys is essential to meet the rapid development of steel industry. Recently, rich-manganese slag containing high grade Mn (>40%), low Fe (1%) and P (<0.03%) is considered as superior raw materials for manganese alloys. While the sinters made from manganese ores are major raw materials for producing rich-manganese slag with the increasing exhaustion of natural rich manganese lump ores [3-5]."

Jan 1, 2013

By Guohua Bai, Lin Zhang, Shan He, Xuling Chen, Min Gan, Xiaohui Fan, Yanbin Tang

"For reducing the dust content in flue gas during copper smelting in the Ausmelt, technologies and mechanism of strengthening the pelletizing of copper concentrate were studied. The results show that adding bentonite, organic binder or composite binder can effectively enhance the strength of green pellet and reduce the rate of shedding powder in drying process, and composite binder works best. When adding 1 % of composite binder, the drop strength of green pellet increased from 1.9 times/P to 4.5 times/P, the rate of damage dropping from 2 m reduced from 50.12% to 13.08% and the rate of shedding powder reduced from 60.28% to 25.13% at drying temperature of 400111. In addition, the mechanism of binder absorbed in the surface of mineral was investigated by infrared spectroscopy. The results showed that composite binder absorbed in the surface of copper concentrate was in the form of chemisorptions, which made hydrophilic enhanced, while bentonite absorbed in the surface of copper concentrate was physisorption.IntroductionWith the technologies of copper smelting developing, the equipment of copper smelting steps into a large-scale and efficient level in recent years. As Ausmelt smelting is characterized by being efficient, environmentally-friendly and energy-saving, it is generally recognized by the enterprises of copper smelting [l]. The process of Ausmelt smelting starts with materials mixing, and then pelletizing. From this point onwards, pelletized balls are charged to the top of the furnace, undergoing drying and smelting reaction[2]. Since copper concentrate is fine-grained, directly adding into smelting furnace can make it blown out of the furnace together with the airflow upwards, rendering flue gas high in flue dust, which can cause the loss of concentrate greatly, and make smelting environment poor as well. The concentrate transported into the furnace and smelted after disc balling is conducive to improve the capacity of melting furnace during copper concentrate smelting, reduce the powder shedding rate and improve enterprise benefits."

Jan 1, 2013

By In-Hyeok Choi

Currently, spent V2O5–WO3/TiO2 catalysts contribute significant amounts of solid waste following increasing levels of global demand. V2O5–WO3/ TiO2 catalysts usually consist of TiO2 anatase as a supporting oxide, vanadium as a catalytic agent, and other promoters such as tungsten, silicon, and calcium. Although vanadium is the main catalytic agent, a relatively high content of tungsten (WO3, 7–10 wt%) typically exists compared to vanadium (0.5–1.5 wt%). Considering the irreplaceable properties and industrial importance of tungsten, a feasible method for the recycling of spent V2O5–WO3/TiO2 catalyst should be established to utilize it as a secondary source. This paper presents a process to recover tungsten from spent V2O5–WO3/TiO2 catalyst. The processes proposed here involving roasting, decomposition using HCl, ammonia leaching, and crystallization. Within the process, ammonium paratungstate (71 wt% as WO3) is obtained as a final product. The total yield rate of tungsten from feedstock was found to be 96.3%.

By Chris Twigge-Molecey

As emission constraints for metallurgical plants become more difficult to meet; control of major, multi-vessel, flue systems become more critical. Control instabilities can result in significant loss of system capacity or emissions to the environment. This paper will discuss the use of dynamic simulation techniques to optimize both the design and control strategies for these systems. A significant ,safety hazard is associated with pressure excursions from process upsets or equipment failures. Pressure rise rates of up to 10 kPajsec can occur. These cannot-be followed by conventional controls. Fail-safe high speed venting is required to protect both the furnaces and operating personnel&apos;. Design options, sizing techniques and practical problems are discussed.

Jan 1, 1992

By Edward Rosenberg

The synthesis and characterization of silica polyamine composites modified with a variety of sulfur containing ligands is described. The two most successful ligands in terms of sulfur in-corporation and mercury capture are ethylene sulfide and carbon disulfide. The ethylene sulfide forms either an amino mercaptane or a polysulfide upon reaction with amino groups on the composite. The carbon disulfide undoubtedly forms a dithiocarbamate functional group upon reaction of the amino group under basic conditions. Both materials posses excellent capture kinetics and capacities for mercury, Once captured, the mercury is extremely difficult to remove from the composite materials, even with concentrated acids, and they easily pass the TCLP test. The materials are compared with related thioether modified silica polyamine composites and appropriate potential applications are discussed.

Jan 1, 2003

By Adriana de Aquino Soeiro da Silva, Joao Alves Sampaioa, Luiz Carlos Bertolino, Francisco Manoel Garrido, Marta Eloisa Medeiros

"Brazil has a large agricultural potential and its production success is related to the chemicaland physical soil characteristics. Therefore, the demand in the use of a great quantity offertilizers to compensate the low amount of nutrients in the soil includes about 40% of foodproduction costs. In order to develop economical alternatives to traditional fertilizers, rockswith potential use in agriculture will be studied. In this work the potassium rock, a greensandslate, will be chemically and structurally characterized for the development of a potassiumthermophosphate. This alternative fertilizer will be obtained based on a fusion of a ponderedmixture of potassium, magnesium and phosphate rocks to be applied in the Brazilianagriculture. Preliminary characterization results indicate that the greensand slate presents ahigh percentage of glauconite, quartz and micas.Keywords: Potassium thermophosphate, alternative fertilizers, greensand slate.IntroductionBrazil has a great agricultural potential and its production success is closely related to thesoil's chemical and physical characteristics. However, the country's soils present lownutrients content and high acidity due to weather conditions. Thus, the use of a high amountof fertilizers makes up for the soils' lack of nutrients and accounts for 40% of food productioncosts. Therefore, research on obtaining new alternative fertilizers is a constant worry due tothe increase on food demand [ 1].The lack of raw material for the preparation of NPK fertilizers in Brazil is a concern and theissue of potassium fertilizers a priority. Such a fact is because in 2008 only 608.000 tons ofKCl were produced, corresponding to just 10% of the Brazilian necessity. Thus, the use ofrocks as agricultural nutrients can contribute to reduce the need for industrial fertilizers.This way, the development of a new agricultural raw material originated from a rock thatalready exists in the country's soil is of great importance for the mineral and agriculturalsectors."

Jan 1, 2011

By Larry Southwick

This Peirce-Smith Converting Centennial symposium is celebrating the contributions of two men, William Peirce and E.A.C. Smith, in advancing technology allowing the copper industry to realize its full potential. However, theirs is representative of a larger story: New, simpler technology releasing the stranglehold of older, more complicated technology, new developments in vessel configuration and design finding alternate routes around dead ends in operability, advances in technique and concepts removing roadblocks of cycle time and capacity, and overall innovation opening up vast new reserves around the world to those companies willing to embrace those improvements. Our story is also one of personalities, stubborn smeltermen versus the innovators, those inside the industry versus those from outside. It is a story of an initial borrowing from the steel industry, but also Peirce and Smith, from the refining end of the copper business, taking the ideas of Baggaley from Pittsburgh’s steel and airbrake industry, who built on what Hollway, Manhès and David, Douglas, and others had done in smelter tests, further to compete with the previous primacy and closely held expertise of the copper smeltermen in Wales. These advances have been well recorded in photographs taken over the last 150 years. A number were submitted especially for this symposium. Many others were published in the mining and metallurgy press of the times. Several mining schools also retained copies of photos either taken during field trips, or donated to the school by alumni and operating companies. This presentation will provide a selection and discussion from these sources of “converters in action”, describing the various designs, operations and developments depicted. The focus here will be on the first roughly 60 years of copper converter development, from Bessemer’s days at the dawn of this new idea, up to and slightly past the time of initial adoption of Peirce and Smith’s designs.

Jan 1, 2009

By Y. Kumagai, F. A. Souza

"Electroless plating process has been used in many fields such as automobile and electronic industries. Solutions used in these processes must be disposed or treated. Commonly, in these solutions metal ions, organic materials and others chemicals are in very high concentration. It is very difficult to keep the environmental regulations for disposal of these materials, and the cost of the plating process becomes higher.The objective of this study was to investigate the recovery of components of those baths in order to decrease the cost of the plating process as well as to meet the environmental regulation.In this study the recovery metal ions, sulfate ions, phosphite ions and organic compounds were investigated. Organic compounds used in electroless plating solutions are the organic acids. In this work the solvent extraction of the most used organic acids included citric, lactic, succinic, tartaric and malic was studied. The solvent phase considered in these studies was ethyl acetate.About 95% of the metal ion was recovered by chemical plating onto mica powder. The hypophosphite remained is oxidized to phosphite and with the sulfate ion, both are recovered as calcium salts by selective precipitation in pH 7 and 2 respectively. Organic acids were recovered by solvent extraction using ethyl acetate as solvent phase and the best results were for lactic acid and succinic acid.Along with this study, was developed the analytical parameters to perform wastewater analysis by using Ion Chromatography, High Performance Liquid Chromatography (HPLC), Fourrier Transform Infrared Spectroscopy (FTIR). Ion chromatography was used to perform analysis of sulfate and phosphite ions in liquid matrix, HPLC was used to perform analysis of organic acids in liquid matrix and FTIR was used for characterization of the solids obtained in the recovery processes."

Jan 1, 1997

By Ma Lijuan, Zhang Yubing, Wang Bo, Sun Huilan

The effect of lime ratio on phase composition and alumina leaching property of MgO-contained calcium aluminate clinker were investigated by analytical reagent, the XRD analysis of its mechanism was discussed. The results showed that: when the sintering temperature was 1350 ℃, C/A was 1.4, A/S was 1.3 and the content of MgO was 4%, the increase of the C/A promoted the formation of C12A7 and restrained the formation of Q-phase. The alumina-leaching ratio of the clinker (A/S was 1.3) was increased from 74.33% to 91.34% when the content of CaO was 5.21%.

Jan 1, 2015

By C. J. Newman

In January 1999, a redesign of the Kennecott Flash Converting furnace settler was initiated to enhance furnace integrity and extend furnace life. This furnace uses Kennecott-Outokumpu Flash Converting technology to produce copper directly from copper matte. A detailed assessment was made of all technology available around the world before making a decision on the design features to be incorporated in the new design. The new design includes the following: redesign of all sidewall cooling elements to include the latest cooling element technology; redesign of the furnace hearth to include a stadium hearth at the reaction shaft end of the furnace; redesign of the furnace hearth to include a stepped hearth design adjacent to the furnace sidewalls; addition of flat settler roof cooling elements .around the reaction shaft; replacement of reaction shaft transition elements with an improved design and improvements to the furnace cooling element monitoring systems. The Flash Converting furnace was shut down on a planned basis in July 2001 to implement these improvements after 29 months of operation, converting more than 1,000,000 tonnes of matte. During the 30 day shut down, the improvements were successfully completed, with furnace start up in August 2001

Jan 1, 2002

By Larry M. Southwick

Steel mill electric arc furnace dust is a RCRA listed hazardous waste and its treatment and/or disposal are regulated by a complex set of rules. These regulations were originally established to encourage recovery and recycling of valuable components. For EAF dust, the more valuable constituents include zinc, lead, cadmium and iron. In fact, current trends are in the opposite direction, as the regulations have complicated the ability to commercialize new treatment technologies and created substantial roadblocks and liabilities for processors. As a result, almost half of the EAF dust generated in 1997 will be landfilled. The problems are compounded by difficult processing requirements, less than sterling examples of technology development and mechanical and operating problems. This paper explores some options to simplify the processing requirements and thereby easing difficulties in commercializing new technologies and expediting the recycling of recovered metals. Dust processing usually includes a simple step followed by two complicated steps. The simple step is fuming of heavy metals away from iron and other residues. The complex steps are (1) separating and purifying the heavy metals and (2) upgrading the iron residue. The first complex step can be simplified by producing an intermediate product that is amenable to processing by zinc refiners. This route benefits from the currently underutilized (by dust processors) resource offered by refiners, who have experience in and existing processes for separation and purification of zinc-based heavy metals. Various processes and their associated product options are reviewed and compared. Future directions for dust processing developments are suggested.

Jan 1, 1998

By Gus Van Weert

Hydrometallurgical oxidation of sulphides is capital and energy intensive, with autoclave and bio-technology competing for lowest overall cost status. The use of surface aerators instead of stirred tank reactors could provide lower costs for bio-oxidation of concentrates. With this in mind, the Delft Inclined Plate reactor was designed with inclined plates above a settler shaped reactor to continuously return slurry from the lowest point in the settler to the surface of the liquid. The multiplate superstructure overcomes the scale-up restriction of the standard circular surface aeration patterns. DIP aerator energy and volume requirements for oxygen transfer from air will be presented in terms of kg O2/kWh and kg O2/m3/h transferred as a function of wt % sand in the slurry and compared to stirred tank performance. Scale up from the 4 m3 pilot unit will be discussed.

Jan 1, 1996

MODELLING FOR DESIGN AND CONTROL AT KALGOORLIE NICKEL SMELTER Modelling at KNS has been driven by a need to have better tools to answer questions about control, design and optimisation of the plant. This paper describes a number of modelling tools developed for use at KNS and how the development of modelling tools fits with a design and control strategy. In the area of control, a thermodynamic model has been developed to allow process parameters to be calculated. The model allows for the automatic selection of data from a laboratory data base, desired operating set points are input and the operating parameters are calculated. The model has the ability to adjust the burner efficiency and the furnace heat loss depending upon conditions. To assist with the testing of proposed furnace design changes, various mathematical models of the burner and shaft have been created using PHOENICS. These models are particularly well suited to combustion heat transfer and flow aspects of both the burners and shaft. Validation of these models have been based on novel sampling and measuring techniques in the shaft and also by using scale and cold models. Overall plant energy and cost structures can be analysed using a flowsheet simulation, developed to evaluate potential alterations to the plant flowsheet. This model system allows the global evaluation of process changes.

Jan 1, 1993

By H. Y. Sohn, Joshua E. Ramos, Moo Eob Choi

"A new technology for ironmaking based on direct gaseous reduction of iron ore concentrate is under development. This technology would drastically lower CO2 emission and reduce energy consumption by nearly 38% of the blast furnace requirements. Experiments were performed using iron oxide concentrate at 1150oC in a bench-scale facility, which was the highest temperature that could be reached in the facility. The reduction extent was determined at residence times of 3.5 - 5.5 seconds in which the reduction extent approached 43% with 0% excess H2 and 95% with 860% excess H2. Separate kinetics measurements showed that the rate is much faster at 1200 - 1400 oC. Experiments were also carried out using syngas (mixtures of H2 + CO). About 90% reduction in 3.5 seconds with 860% excess hydrogen contained in the syngas demonstrated sufficiently fast reduction for a suspension process and the feasibility of usingsyngas instead of pure hydrogen.IntroductionDespite the improvements in the modern blast furnace (BF) process, it suffers from many drawbacks. The process requires the feed in the form of sinters or pellets and high-grade coking coal. Thus, BF iron production is projected to decrease gradually [1]. The main factors for this are the environmental regulations [2] and the high capital investment cost.A large number of new ironmaking technologies have been developed or are under development [3]. Most of these processes, however, are not sufficiently intensive to replace the blast furnace because they cannot be operated at high temperatures due to the sticking and fusion of particles. Therefore, a new technology is under development for producing iron directly from fine concentrates by a gas-solid suspension technology, which would reduce energy consumption by about 38% of the amount required by the blast furnace and drastically lower environmental pollution, especially CO2 emission, from the steel industry."

Jan 1, 2009

By Magnus Ek

After the installation of three new converters as part of the recent expansion of the Rönnskär smelter completed in 2000 work continues to further improve the converter operation. The converter upgrade led to an increase in blister copper taps from 150 tons per batch to more than 300 tons. The total cathode copper production increased from 130,000 tons in 1999 to 230,000 tons in 2001, the first year in full production. In recent years focus has been to improve operating practise, maximize the blowing time, extend the converter campaigns hence to reduce the specific brick consumption and improve the converter slag composition.

Jan 1, 2005

By Shinroku Matsuzaki

Data the measurement sensor installed with spatial distribution on the blast furnace were successively accumulated online from the process computer to the database system over a long period. This is a new system that accurately considers the relation with the installation position of each sensor, and picture computerization of the measurement data was developed. The overall operation state of a blast furnace, which skilled operators can see in their mind?s eye, was objectively visualized as pictorial information.

Jan 1, 2006

By QinGuo, Shenghui Guo, Jinhui Peng, Linqing Dai, Libo Zhang

This paper adopts a simple and novel preparation. Taking cellulose as a template, a tubular morphology structure of micro/nano ZnO crystals was obtained by microwave roasting at high temperature. The higher the microwave roasting temperature, the larger the degree of crystallization. The experiments indicate that the best photo catalytic effect can be obtained at 850 : At this temperature, the oxidation of cellulose is complete. Large quantities of hexagonal shaped ZnO crystal can be observed, specifically the (0001) crystal face. Under ultraviolet-visible irradiation, taking long arc mercury lamp as light source, the material had good photocatalytic activity. The decomposing efficiency of methylene blue reaches 97% in 60min, which is superior to that of preparations without templates at the same temperature.

Jan 1, 2016

By Kandipati Sreenivasarao

Ion and precipitate flotation involve adding an appropriate collector to aqueous solutions containing metal ions, to form hydrophobic metal-collector complexes or precipitates that can be removed by flotation. With a better fundamental understanding of the effects of physical, engineering and chemical parameters on the performance, ion and precipitate flotation techniques could usefully complement techniques now available for removing metal ions from dilute solutions. The removal of Cu(II), Pb(II), Cd(II), Cr(III) and Cr(V1) has been studied, using different types of collector, according to the nature of the metal-bearing species. The effects of collector/metal ion ratio, and solution and froth height on the flotation kinetics, bubble coverage by the metal-collector complex, recovery of metal and effluent quality are reported. The observed behavior is related to the solubility products of the metal-collector complexes, which were also determined.

Jan 1, 1994

By Francis C. Furman

Microscopic evidence indicates that the high sinterability of certain commercial dolomites is tied to specific dolomite textural characteristics. This study encompasses detailed characterization of the unprocessed dolomite and sintering doloma results. The chemical and mineralogical compositions, insoluble residue, chemistry homogeneity, crystal size, primary carbonate texture, secondary dolomite texture, deformation structure, porosity type, porosity, and density of the raw dolomite were observed. These characteristics are compared with sintering trials of <74um powder-compacts samples in which holding times were varied. The evolution of the dolomite characteristics are reviewed and related to the final sintered doloma characteristics. The critical characteristics of a single-stage sintering brick dolomite are the following: 1) primary oolitic texture, 2) dolomite purity, 3) dolomite stoichiometry 4) minimal impurities, less than 1 weight {%} Fe2O3 Al2O3 and SiO2, 5) chemical homogeneity, 6) high density, 7) very low porosity, S) very coarse homogeneous crystallinity, 9) nonplanar dolomite texture, 10) abundant strain related slip microdeformation structures, 11) minimal subsequent alteration. Even with grinding to <74um the nonplanar dolomite texture and slip deformation still have a major effect on doloma sintered density. The three newly identified characteristics of single-stage sintered refractory brick dolomite are their primary oolitic texture, secondary nonplanar texture and abundance of stress related microdeformation structures. The primary oolitic texture reflects a homogeneous pure carbonate with respect to chemistry and crystal size secondary nonplanar texture produces crystals with large surface area to volume ratio. Stress related slip deformation moves CO, groups in to the same site of another CO, group but different orientation which is very unstable. All of these characteristics may facilitate the formation of higher density dolorna sinters.

Jan 1, 1995