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By Deborah A. Kopsick

Several minerals were observed and collected in a small gully originating from a weathered coal processing waste (gob) pile in Barton County, Missouri. The rapid alteration of these various minerals after collection suggested that they might represent a dehydration sequence. X-ray diffraction of the dehydrated and rehydrated minerals deposited on the gob pile indicated the presence of the monohydrate and heptahydrate forms of ferrous sulfate, szomolnokite and melanterite respectively. The occurrence of melanterite (FeSO4.7H2O), was limited to isolated areas of ponded water while szomolnokite (FeSO4.H2O), was associated with the outwash areas of the pile. Laboratory dehydration of melanterite collected at the gob pile revealed the formation of rozenite (FeSO4.4H2O), an intermediate form of ferrous sulfate. Szomolnokite was shown to be the stable form of these ferrous sulfates during these experiments while melanterite and rozenite were shown to alter readily. Chemical analysis of szomolnokite revealed enrichment in Fe, Mg, Zn, Cd, Cu and Mn relative to the chemical composition of the gob ad the lechate generated from the gob wastes. Although this gob pile had been weathering for more than 35 years, significant concentrations of trace metals were still being released from the pile through the generation of leachate and the formation of various soluble metal enriched ferrous sulfate minerals.

Jan 1, 1982

By Jie Ma, Shun-Li Zhao, Jian Zhao, Jie-Yu Zhang

"Microstructural morphology evolution of Ni-45wt.%Mo droplets during rapid solidification process was investigated using an advanced modified 3D cellular automaton-finite element(CAFE) model by CALCOSOFT software. The model was modified by User-defined functions (UDFs) and validated with experimental solidification microstructural morphology of Ni-45wt.%Mo droplets available in the literature. Then, the influences of convection heat transfer coefficient, superheat of the alloy droplets and droplets size were investigated during the rapid solidification process. The predictions show that microstructural morphology is obviously sensitive to convection heat transfer coefficient and droplet size. With the decrease of convection heat transfer coefficient, the grain density decreases. In addition, the decrease of the droplet size could obtain refined microstructure. However, decrease the superheat ofNi-45wt.%Mo droplets has little effect on microstructural morphology.IntroductionFor several decades, much attention has been paid to undercooled alloy droplets of rapid solidification process for which can obtain refined microstructure, decreased microsegregation and extended solubility of alloying elements [1-3]. Extensive prior work shows that solidification of droplets plays an essential role in advanced material properties [ 4]. Consequently, it is very important to investigate the microstructural morphology evolution, especially for dendrite growth during non-equilibrium solidification process, for dendrite growth reflected the kinetics of the crystal growth process."

Jan 1, 2013

By B. Q. Li, R. A. Mirshams

"A numerical algorithm is described for the simultaneous prediction of the thermomechanical behavior of the materials and microstructure evolption during metal forging. The numerical development is based on the finite element solution of the thermoviscoplastic deformation of metals coupled with the internal state variable model describing the microstructure evolution involving work hardening, recovery, recrystallization and grain size distribution. The finite element code for rigid viscoplastic deformation is developed based on the modification of the existing code for the thermal and fluid flow calculations. The code is tested against and compares well with the results reported in literature. The procedures for the integration of the · rnicrostructure model into the macro finite element model are described. Results are presented showing the characteristics of materials dynamics and mechanical deformation during simple metal forging processes.IntroductionIn industrial deformation processes such as hot rolling and forging, the workpiece undergoes both macroscopic plastic deformations and microstructural evolution. A computer model that allows to predict both materials dynamics and macroscopic deformation is obviously more useful for both fundamental understanding and deformation process optimization. For some industrial applications, especially those involving novel, light and high strength materials, such an integrated model is critical in that both materials and thermomechanical 'behavior during forging must be carefully controlled to obtain the products that meet the desired strength requirement [I]."

Jan 1, 2000

By Xiao Long, Ting Wu, Lilong Zhu, Qian Wang, Shengping He

"During the continuous casting of peritectic steel slabs, mould fluxes with high crystallization capacity are usually chosen for improving slab surface quality. However, the lubrication condition of casting shell also could be deteriorated. Since precipitation of crystals within liquid slag film can change the composition and property of liquid slag over solid-liquid slag film interface region, its impacts on continuous casting process also are not clear. In order to clear this phenomenon, an experiment method was put forward, and mould fluxes for peritectic steel slabs continuous casting were selected and examined. The results reveal that after crystals have been separated, the crystallization capacity of leftover liquid slag increased with different levels, which could deteriorate the lubrication condition of casting shell and cause a series of problems. Thereby, mould fluxes with high crystallization capacity at beginning for heat transfer control and then weaker after crystallization should be considered in the future.IntroductionIn the continuous casting of peritectic steel slabs, contradiction between heat transfer control and slab shell lubrication by mould fluxes has been treated as a key problem for maintaining a smooth manufacturing process [ 1]. Strong and uneven horizontal heat flux over the meniscus region will cause uneven solidification of casting shell, especially for peritectic steel slab with enormous volume change caused by phase transition. All of those could cause surface defects like longitudinal crack [2-4]."

Jan 1, 2013

By W. G. Davenport

Inco flash smelting blows industrial oxygen, dried Cu"Fe-S concentrate, Si02 flux and recycle materials horizontally into a hot (-1500 K) furnace. Once in the furnace, the oxygen reacts with the concentrate by Reactions 1.1, 1.2 and 1.3 to give: (a) liquid matte, 55 to 60 mass%Cu (b) liquid slag, 1 to 2 mass% Cu (c) off gas, 60 to 75 volume % S02. The matte is tapped into ladles and sent to converting, Fig. 1.3. The slag is tapped into ladles, and sent to a stockpile; with or without a Cu-from-slagremoval step. The off gas is water-quenched, cleaned of dust and sent to a sulfudc acid plant. The [nco flash furnace is also used to recover Cu from molten recycle converter slag. The slag is poured' into the furnace via a steel chute and water-cooled door, Fig. 3.1. In 2000 there are five Inco flash furnaces in operation: at Almalyk, Uzbekistan (Ushakov, et at. 1975); Hayden, Arizona (Marczeski and Aldrich 1986); Hudey. New Mexico (Belew and Partelpoeg, 1993); and Sudbury, Ontario (two furnaces, Carr etal, 1997, Humphris et ai, 1997; Molino et ai, 1997). The Almalyk, Hayden and Hurley furnaces smelt Cu-Fe-S concentrates. The Sudbury furnaces smelt Ni-Cu-Co~Fe-S concentrates'to produce -45% Ni+Cu+Co matte and -1% Ni+Cu+Co slag.

Jan 1, 2001

By Qingyu Deng, Shiwei Ma, Guibao Qiu, Hua Wang

"The flow behavior of the blast furnace slag bearing titanium, like viscosity, play an importance role during the iron-making process with the vanadium-titanium magnetite, which is a very special minerals in Panzhihua, China. The dependency of the viscosity on the chemical composition like TiO2, Al2O3, MgO, binary basicity (CaO/SiO2), temperature, reaction time were studied. The experiments showed that the viscosity decreased with the increase of TiO2, MgO content and binary basicity, and it increased with the increase of Al2O3 content and temperature. The viscosity showed a slight decrease within 60mins’ reaction with graphite crucible, however, it increased rapidly afterwards with the formation of Ti(C, N).IntroductionThe ordinary iron ore has been an essential part of raw materials for vanadium-titanium magnetite smelting in Panzhihua to avoid a series of problems, such as slag thickening, adhesive bond of slag and hot metal, etc. The ratio of vanadium-titanium magnetite has been decreased gradually since 1970s, and has down to about 65% now. However, with the substantial appreciation of price of imported ordinary iron ore, Panzhihua Iron and Steel Group aims to increase the ratio of vanadium-titanium magnetite and decrease the dependence on ordinary iron ore in order to lower the cost of smelting process."

Jan 1, 2012

By Alexander I. Raitchenko

"An electroconductive viscous liquid may flow in laminar or turbulent regime under Lorentz-force generated by the intercrossed electric current and magnetic field. When there is a starting flat layer between hard and free boundaries with surface tension the spatial Lorentz-force can create a specific stationary regime of flow: the plane free surface will transform into the wavy one, and the movement in the depth will be not laminar and not turbulent, but this regime will be characterized by organized forms with indications of ""rolling of long cylindrical drops"". Wave-length is determined by the viscosity, the density, the surface tension, the average thickness of layer, and Lorentz-force. ·The limit of wavy regime is determined by most long of wave which is directly proportional to the critical value of specific flow and inversely proportional to the kinetic viscosity. The proper critical value of Reynolds number is determined by the dimensionless combination containing surface tension, density, viscosity, and Lorentz-force. The mentioned dimensio.nless combination in our case is some criterion substituting the known Kapitsa number for case of the thin viscous liquid layers under gravity. Spreading of admixture by mechanism of wavy regime is more rapid than by common diffusion or by laminar flow. The suggested conception can be a contribution into the theoretical basis for elaboration of some specific liquid metals technologies."

Jan 1, 1999

By Yuuki Hagio, Hiroyuki Tobo, Michihiro Kuwayama, Yasutaka Ta

"Reduction of CO2 emission is necessary to remedy global warming, however, promising approaches of CO2 separation require a large amount of energy. Molten slag, which is generated as by-product of steel production, has high temperature, but its energy has not been harnessed. To recover the thermal energy from the slag and to apply to separation of CO2 are economical and environmental conscious ways. We propose a new heat recovery system, in which, molten slag is solidified continuously on water-cooled roll and the solidified slag plates are charged into counter-current heat recovery equipment. In laboratory scale experiments, heat recovery ratio of more than 30% was acchived by controlling the thickness of slag.IntroductionThe steel industry in Japan has been working on the projects of ""Environmentally Harmonized Steelmaking Process Technology Development (COURSE50)"". COURSE50 aims at developing technologies to reduce CO2 emissions by approximately 30%. One of the main technologies is to capture and recover CO2 from blast furnace gas using chemical absorbents to regenerate CO2-laden chemical absorbents by separating CO2 from the absorbents. As one of the solutions, JFE Steel Corporation has been developing sensible heat recovery process from steelmaking slag. It is effective to recover and use unutilized high temperature waste heat within a steel plant as the thermal energy required."

Jan 1, 2012

By S. de Vries, B. Wasmund, J. Metric, N. Voerrnann, S. Kasinger

Gulf Chemical & Metallurgical Corporation (GCMC) operates a circular DC electric smelting furnace to treat nickel and cobalt bearing residues at its plant in Freeport, Texas. The furnace, originally built by others, has experienced problems including runouts through the hearth and the lower sidewall. Hatch has designed several improvements to the furnace to alleviate these problems. The single anode at the centre of the hearth was replaced with a patented system of twelve air-cooled copper anodes evenly spaced around the furnace lower sidewall. The DC power supply comprises two transformers and two rectifiers operating in parallel. The water-cooling system on the bottom and lower sidewall shell plates was replaced with an air-cooling system using copper cooling fins. The existing row of water-cooled copper coolers in the metal bath zone was re-designed for greater heat removal capacity and better element joint sealing, and a new row of water-cooled copper coolers was added to cool both the alumina bath and freeboard zones. The existing water-cooled metal and alumina tapblocks were also re-designed for more robust cooling. A binding system was added to provide refractory compression that reduces the risk of liquid leaks. Finally, the furnace tilting frame was relocated to the top of the furnace where it is less likely to be damaged.

Jan 1, 2000

By Ramasamy Santhanam

"India’s present annual marine fish catch is 2.9 million tonnes and its low value fishes such as sardines, sciaenids, goat fishes and leiognathids amount to 60%. The fish meal obtained from these resources is mainly used presently as an ingredient in live stock and aquaculture feeds. These fishes offer vast scope in the production of pet foods. Pet foods prepared with leiognathid fish meal (60%), maize flour (10%), wheat flour (5%), vitamin and mineral mixture (5%) and water (20%) and experimented with 50 cats and 50 dogs were found to be ideal. Depending on protein level, feeds are being formulated for experimenting with more number of pet animals. Training programmes are also planned for unemployed people to popularize pet foods for commercial purposes.IntroductionIndia’s present annual marine fish catch is 2.9 million tonnes and low-value fishes sucha s sardines (Sardinella albella, s. gibbosa, S. fimbriata and S. melanura); sciaenids (Otolithus spp. and Jhonius dussumieri); engraulids (Stolephorus indicus); and leiognathids Leiognathus bindus, L. equilus and Gazza achlamys) constitute 60% (Figure 1)[1]. The fish meal obtained from these resources is now mainly used as an ingredient in livestock, poultry and aquaculture feeds. Considering the rich nutritional status of these low-value fishes, it is felt that these resources could be converted into value-added products viz. pet foods."

Jan 1, 2008

By V. Madhusudhan Rao

Fly ash is a finely divide non ? combustible material obtained as a by ? product of coal combustion. It is a major by ? product of coal based thermal power stations. Until recent past it was considered as a waste and highly polluting material. However its formation can only be minimized by using suitable technology in the boilers. In recent past it is found that Fly ash has many end uses and it has proven itself to be a potential construction material. But the suitability of fly ash for various applications largely depends on the amount of unburned carbon, which is turn depends on the firing method. Fly ash samples from various power plants existing in India using a fluidized bed method and pulverized bed were analyzed and a comparison of these two firing methods was carried. This paper deals with the compositional requirements for fly ash used for the fabrication of insulating doors using AAC (Aerated Autoclave Concrete) and the methods employed to make fly ash suitable for this purpose. It also includes the latest ?U? beam technology for effective fly ash recycle. If the by products of coal combustion from power plants like fly ash as the paper stresses are utilized properly, it is not an exaggeration to say that power generation is possible with absolutely zero cost.

Jan 1, 2006

By F. Mucciardi

With the increasing trend to continuous smelting and converting, granulation of copper matte is gaining prominence as a means of decoupling the smelting and converting operations. Moreover, granulation is also being seen as a possible avenue to using higher grade oxygen in converters. By feeding cold solid matte, the oxygen concentration can be increased to compensate for the lower enthalpy feed. This leads to a higher grade of SO2 in the off gas and a lower total flow rate. Current granulation technology relies on the cooling of a falling matte film by water jets. This technology while effective has several drawbacks including those related to safety. Noranda and McGill University have developed a new process (patent pending) for solidifying copper matte (or slag). It overcomes many of the negatives of current technology. The system is based on an air cooled twin roll caster. This: new system uses no water and instead incorporates heat pipe technology to transfer the heat from the solidifying matte to the cooling air to produce a thin strip of 1 to 2 mm in thickness. Testing of a prototype unit demonstrated its viability. This paper describes this newly developed, twin roll casting system that is completely waterless. The advantages of this process as well as the findings from several tests are also detailed.

Jan 1, 1999

By Chuan-fu Zhang

The fibrous precursor can be obtained by coordination precipitation process, using oxalate, cobalt chloride and ammonia. XRD pattern of precursor precipitated at pH=9.0 is different from that of ß-CoC2O4?2H2O precipitated at pH=1.0 which indicates that the precursor powders are one type of cobalt complex. According to the results of element analysis and IR spectra, it can be inferred that the composition of the precursor is [Co(NH3)x]C2O4?H2O(x=1.2?..6) formed by the coordination reaction at pH=9.00 in the Co(II)-C2O42--NH3-NH4+-H2O system. It?s found that the fibrous cobalt powders greatly inherited the morphologies of the precursors. Many factors could affect the formation of the fibrous cobalt precursor powders, such as the initial Co2+concentration, pH value and so on. The SEM images show how they influence the morphologies of the precursor powders. By adding proper surfactant, the dispersion of the precursor powders would be improved. At last, the final product-fibrous cobalt powders which are about 0.3~0.5min size and 40~60 in aspect ratio were produced by thermal decomposition of fibrous cobalt complex at 400~500°C in the weak reducing atmosphere.

Jan 1, 2006

By J. Garvey

The new Cyprus Miami electrolytic copper refinery was commissioned in October 1994. The refinery has been operating at its design capacity of 190,000 short tons per year, and in recent months to 110% of design capacity, producing high-grade electrolytic copper cathodes. Basic and detailed engineering, performed by Fluor Daniel Mining and Minerals, incorporated state-of-the-art technology, including stainless steel cathodes, automated electrode handling, fine-filtering of the commercial electrolyte, autoclave leaching of the anode slimes and other techniques. The major design goals have been safety of operation and quality of the product. Relatively high cathode current densities of 30 amperes per square foot and greater have been applied since start-up. Cathode current efficiencies of over 94% have been achieved since the latter part of 1997. The cathodes were certified on the Comex and LME markets during 1996. ISO- 9002 certification is in progress and should be completed during the first quarter of next year. This report discusses some of the studies that were performed to obtain an optimum layout for efficient materials handling and to create optimum conditions for producing high quality cathodes. A description of the design and operation of the anode slimes facility, including decopperizing with autoclave leaching, is provided. Finally, a description of the start-up experiences and present operation of the electrorefinery are presented.

Jan 1, 1999

By C. W. Vierrether

Mineralogical analysis contributes directly to the selection of applicable beneficiation techniques for a given site. Tentative remediation methods for use on the Sharon Steel tailings in Midvale, Salt lake County, UT, were determined in part by mineralogical characterization. A systematic characterization scheme was employed to identify mineral species, mineral associations, and grain size. This paper presents the mineral content and distribution data collected for site characterization. This data was used to determine areas that were representative of the total tailings at the Sharon Steel site. Although this was the main focus of characterization, other useful information was obtained. The approximate location of "old jig tails" was identified and insight on possible arsenic, mobility through the pile was also obtained from the mineralogical study.

Jan 1, 1991

By I. D. Reznik

Results of thermodynamic computations have been presented for reactions occurring in the process of segregation roasting of oxide nickel ores to describe more accurately the mechanism of the process. Under conditions of laboratory-scale roasting in combination with close-circuit flotation flow-sheets and magnetic separation, a recovery of 80-82% of nickel into 8 to 10% Ni concentrate and a recovery of up to 66% of cobalt was achieved. Process conditions have been selected for processing of both high-iron and high-magnesium ores. The feasibility of conversion of 94-98% of nickel and cobalt into solution by oxidizing pressure leaching with sulfuric acid has been demonstrated. It has been substantiated that it is reasonable to introduce double-stage segregation roasting.

Jan 1, 2003

By Gudrun A. Saevarsdotti

For decades tile aluminium industry has been practicing gas treatment of aluminium melts. This treatment is of great importance because of its influence on 'impurity" and inclusion removal from the melt. The gas-melt interaction is greatly influenced by the gas composition, melt temperature etc. This paper gives an overview of the interaction between argon-chlorine gas mixtures and the aluminium melt. It covers the thermodynamics of the reaction between the chlorine and a number of different elements commonly found in liquid aluminium, and discusses the behaviour of reaction products in the melt. The paper reports an experimental study of the behaviour of the chlorine-molten aluminium interface, using sodium contaminated aluminium melt with and without the addition of grain refiner.

Jan 1, 1996

By O. E. Omotoso

This study is part of an ongoing investigation to understand the mechanism of stabilization/solidification of hazardous chromium wastes in ordinary Portland cement (OPC). Tricalcium silicate (C3S*),a major component of OPC is mixed with reagent grade Cr(lll) and Cr(VI) solutions, to simulate complex cementiCr waste systems. Scanning electron microscopy (SEM) and energy disperse spectrometry (EDS) were employed to provide microstructural and chemical information. Transmission electron microscopy (TEMlEDS), apart from complimenting the SEM, was used to probe the distribution of Cr in the hydration products of C3S and to provide crystallographic information. 29Si MAS NMR (magic angle spinning - nuclear magnetic resonance) Was used to characterize the influence of Cr on the hydrated silicate structure.

Jan 1, 1995

By D. R. Kreuzer

The sulfide smelting industry is striving for up-scaling their operations by increasing the throughput and efficiencies of the furnaces. The physical phenomena related to refractory materials prevailing in smelters and furnaces are highly complex. The refractory materials are exposed to fairly high temperatures, thermo-mechanical stresses, penetration of pores, erosion and chemical corrosion. The application of numerical simulation tools is needed for the refractory engineering task to consider those phenomena and to evaluate the impact of operational regimes on the refractory design and finally on the integrity of the furnaces. The work discusses case studies of simulations addressing problems and questions related to the refractory design process. Practical simulation approaches which employ simplified models are introduced as the engineering process demands results in a reasonable time.

A study was undertaken to remove the Se from waste solutions using a raw form of the biomass called Iota Chips derived from the seaweed, Eucheuma spinosum. Removal of Se from solutions was investigated as a function of time, pH, conc. of Se in solution (0.1 to 100 ppm) and lota Chips to liquid ratios of 10-2 to 10-5. For solutions containing initial conc. of 0.1 ppm Se, with the addition of Iota Chips at a solid to liquid ratio of 10-3, the Se conc. decreased to 0.03 ppm in about 3 hours. Iota Chips absorption capacity to the Se and its application to the treatment of the metallurgical processing effluents are discussed.

Jan 1, 1992