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By Ray Y. Lin, Sunil G. Warrier

"Low cost processing of metal matrix composites is an essential requirement for this class of materials to be acceptable in commercial application. In an effort to reduce the cost of processing of metal matrix composites, an infrared pressureless liquid infiltration technique has been developed. The salient features of infrared infiltration are that it is rapid, simple and a low cost process. The rapid processing capability causes very little oxide formation on the alloy resulting in both improved wetting and flow characteristics and reduced oxygen contamination in the composite. Thus, vacuum is normally not required. Using infrared inflltration, aluminum and titanium matrix composites have been prepared under an ambient argon atmosphere. Reinforcements in these composites include carbon fibers, silicon carbide Nicalon fibers and Textron's SCS fibers. Microstructural and mechanical test results indicate that completely consolidated composites with good fiber distribution, limited interfacial reaction and high mechanical properties can be manufactured by this process. IntroductionAluminum and titanium matrix composites reinforced with ceramic reinforcements are strong candidates for numerous applications in the aerospace and automotive industries. Aluminum matrix composites are commonly fabricated by either solid state vacuum hot pressing, liquid state pressure infiltration or squeeze casting [1]. Although liquid state pressure infiltration and squeeze casting has significant advantages over solid state processes, the requirement for pressure makes these composites uneconomical for large scale industrial application. Titanium matrix composites are primarily fabricated by solid state diffusion bonding [2]. Pressureless liquid infiltration can significantly reduce the cost of fabrication in both the composite systems. However, during pressureless infiltration processes, several complications concerning the wetting characteristics and chemical compatibility arise."

Jan 1, 1994

By C. M. F. Viera

In this work the properties of a clayey ceramic incorporated, up to 10 wt.%, with three types of wastes from a water treatment plant was evaluated. To determine the physical and mechanical properties such as linear shrinkage, water absorption and diametrical compression, specimens were prepared by 18 MPa uniaxial pressure and then fired in laboratory furnace at 700oC. The results indicated that the wastes incorporation changed the properties of the clayey ceramic. From the results it was found it possible to recycle these wastes into clayey ceramic in low amounts to avoid deleterious effect on the quality of the fired product.

Jan 1, 2008

By K. Abe

Onahama Smelter has two green-charge reverberatory furnaces and the annual smelting capacity is 600 thousand tons copper concentrate. In addition to the concentrate, various kind of industrial wastes has been processed and utilized. First, the brick waste from converter is ground and used as raw material of castable for repairing the copper melt launders. Second, the slag containing calcium-sulfide from other foundry is fed to the reverberatory furnaces. Calcium sulfide is oxidized to CaO. The melting rate of concentrate is accelenlled and the slag loss is decreased. Third, the tip tire made of waste car tire is charged into the reverberatory furnaces as fuel. The steam of waste heat boiler for turbine generators has been increased so as to decrease the electricity cost. Fourth, the sulfur accretion from other chemical plant is blended into the copper concentrate and the sulfur is recovered as the gypsum for sale. Fifth, the processed waste oil has been utilized in the copper concentrate dryer by which the smelting capacity was increased effectively. Consequently, Onahama smelter contributes to the society by processing the wastes to the harmless slag and utilizing them as fuel through the copper smelting.

Jan 1, 1996

By John R. Hugens

Modifications in the ALSCAN method of measuring hydrogen dissolved in liquid aluminum have made it possible to monitor the level of hydrogen dissolved in liquid copper. Measurements from the tundish show a correlation with eddy current readings from the continuously cast and rolled copper rod from the continuous casting and rolling system at Amarillo. The measurements also indicate that the copper in the tundish is supersaturated with hydrogen.

Jan 1, 1994

By Ajay K. Singh

The surface quality demands for galvanized and galvannealed steel sheets by the automotive and appliance industries have been getting increasingly stringent over the past few years. Intensive efforts by Hot-Dip-Galvanizers to meet these demands have resulted in substantial improvement to the hot dip coating process. However, elimination of zinc bath contaminants which directly affect the coated strip surface quality continues to remain a tough challenge. As part of our effort to improve the zinc bath cleanliness, Inland Steel Company has developed a test method to quantitatively measure the contaminants in incoming zinc spelters and establish a specification for incoming zinc quality. The test is currently being used for auditing the incoming zinc quality. The zinc suppliers are also using this test for quality control purposes. The purpose of this paper is to describe the test method and how it has improved the galvanizing operation at Inland.

Jan 1, 1992

By Fathi Habashi

The behavior of pyrite, covellite, and arsenopyrite during leaching is different from other sulfides due to the presence of the disulfide ion, Sl. Arsenopyrite contains in addition, the diarsenide ion, Asl. The disulfide ion undergoes auto-oxidation in high acidity leading to elemental sulfur and sulfide ion formation: The sulfide ion may oxidize further by oxygen to elemental sulfur if high acidity is maintained. In neutral medium, the disulfide ion does not undergo auto-oxidation but oxidizes to thiosulfate then to sulfate: This leads to the two overall reactions observed experimentally: In acid medium and in neutral medium Covellite and arsenopyrite behave similarly.

Jan 1, 1995

By T. S. Montgomery

The performance of carbon-magnesia brick in electric arc furnaces (EAF) is interpreted in light of their observed optical microstructures. Features at the bricks' hot faces were protruding periclase grains, metal globules, graphite-metal contacts and linear void patterns. These features were com-pared to similar features previously seen from microstructures of basic oxygen furnace (BOF) refractories. Modes of formation were sought; an attempt was made to interpret their influence related to wear mechanisms.

Jan 1, 1982

By Anjan Kumari, B. K. Soni, Manis Kumar Jha, A. Vidyadhar, Vinod Kumar

"In the present paper, recovery of valuable metals from the poly-cracked ash obtained by pyrolysis of discarded PCBs has been studied following physical beneficiation and a hydrometallurgical process alternate to smelting. The ash is subjected to comminution for the separation of metallic components from non-metallic fractions by scrubbing, tabling and froth flotation which enriched the metal in the concentrate -97% which was further screened to separate high and low metal concentrate. The finer fraction containing -12% metallic value was leached in acidic solution. Almost all (Cu, Pb, Fe, etc) were leached in 4M HN03 at 90°C in 75 min at a pulp density 100 g/L. The characterization of both ash and residues were made by XRD, EPMA, EDS, etc. to validate the experimental results. The metals from the leach liquor could be recovered/separated using solvent extraction techniques which can further be processed to get pure metal salts/ sheets.IntroductionPrinted circuit boards (PCBs) are an essential component of electrical and electronic equipments (EEEs) as it plays an important role during operation of these devices. The world market of PCBs has reached nearly $60 billion in 2012, with 1.7 percent real growth over 2011 [1]. The diverse technology-driven global market is expected to grow at an average annual rate of 5% by 2014 [2]. The waste EEEs are generated due to replacement of obsolete equipments with modem ones and thus their demand is also increasing rapidly [3]. The discarded e-wastes are being piled up as landfills which affect the environment and cause health threats to living organisms, if not disposed of properly. These e-wastes contain metals some of which are precious, few are hazardous and others as valuable."

Jan 1, 2014

By V. M. Paretsky

Oxygen-flame converting of a solid ground matte containing heavy non-ferrous metals in a wide range of concentrations is one of the perspective trends meeting the demands of modern non-ferrous metallurgy. As. a result, of semicommercial tests on oxygen-flame smelting of nickel matte containing 13,5-17,5% Ni; 0,45-0,65% Co under continuous autogenous conditions a converter matte containing 68 8-75,0% Ni and 0,48-1-,0% Co and ferrite -calcium slag containing 1,4-8,4 Ni and 0,16-0,56 Co were pro¬duced. Nickel recovery in a converter-matte was 76,2%, copper - 58,'2% and cobalt recovery in. a slag was 90%. Slag cleaning in an electric furnace allowed to after-recover nickel and cobalt in an alloy to produce a dumpy slag containing 0,03% Ni and 0,02% Co. The development of modern' ecologically pure energy-saving autogenous technologies of the treatment of sulphide raw materials containing heavy non-ferrous metals makes certain demands of the perfection of a process of converting rich sulphide-metallic intermediate products obtained at autogenous smelting. These-demands were connected first of all with the fact that converting process stages because of process periodicity are more unfavourable from the point of ecology, power intensity and unit stability. Besides, during rich matte treatment the problems connected with heat shortage when using air blast and heat excess-when using top oxygen blast to treat luquid matte a-rise and when enriching air blast by oxygen up to 26% fast erosion of the brickwork of a tuyere zone takes place. The technology of Outokumpu and Kennecott companies-on solid- copper matte converting in a flash smelting furnace using air blast is not universal as its possibilities are limited by certain composition of mattes. Besides, flash smelting to produce highly basic or combined slags requires larger enrichment-of blast by oxygen or extra fuel feed. Naturally a flowsheet with continuous converting of matte of various composition up to white matte production is simple,

Jan 1, 1993

By F. W. Warnaars

Chanarcillo is a historically well-known silver deposit which produced over 100 million ounces. High grade vein-type mineralization is confined to a prominent set of nearly vertical, NNW to NE fractures that intersected limestones, andesites and tuffs of Early Cretaceous age. A significant amount of disseminated silver mineralization extends laterally outward from the fractures for considerable distances in pyritic carbonaceous limestones, whereas more competent volcanic beds rarely contain lateral mineralization. Local exposures of skarns are mostly barren. Silver and minor base metal mineralization was probably formed peripheral to a granodioritic intrusion inferred to exist at shallow depth. Part of this intrusion is exposed nearby where it contains significant hydrothermal mineralization and alteration. This intrusion was dated at 83.8 m.y.

Jan 1, 1987

By I. A. H. Schneiderl

Eichhornia crassipes approaches being a scourge in many parts of the world, .choking waterways and hindering transport upon them. At the same time it is known to readily abstract heavy metal ions from water and, thus, aids in the removal of heavy metals found in such waters. This paper considers the possibility of using specific parts of the plant as an inexpensive adsorbent for the removal of heavy metals from contaminated chemical and mining industry waste waters. In particular the root of the plant was found to be an excellent accumulator of 'heavy metal ions including uranium from solution. It is. also suggested that dried roots of the plant ?might be placed in simple bags and used in a very low cost metal ion removal system.

Jan 1, 1995

By Fernando Castro

Electric furnace steelmaking dust is a polluting residue that needs to be treated in order to recover metals contained and to produce an environmentally acceptable residue. Some hydrometallurgical approaches for its treatment have been evaluated, namely: caustic soda leaching followed by electrolytic recovery of zinc, ammonia leaching followed by zinc compounds precipitation and acetic acid leaching followed by lead, zinc hydroxide and gypsum precipitation.

Jan 1, 1992

By Toshihide Takenaka

The management of radioactivated stainless steel from a terminated nuclear reactor will become an important subject in the near future. The separation of the elements in stainless steel should be effective to reduce the management labor. In this study, the separation of the elements in stainless steel by an electrorefining tcchnique was investigated in an aqueous solution. The electrochemical reactions of the elements in stainless steel werc studied by voltammetry and potentio-static electrolysis was carried out. A stainless steel anode was dissolved electro-chcmically with good anodic current etliciency in a chloride solution. The residue, where Ni was concentrated, was found on the anode after electrolysis. The electrodeposit in a stainless steel cathode consisted mainly of Fe and Cr and the Ni content in it was less than 0.5wt% under suitable condition. It is concluded that an electrorefining technique is effective for the separation of the elements in stainless steel.

Jan 1, 2003

By Lifeng Zhang, Zineb Benouahmane, Yaqiong Li

Experimental oxidation tests at high temperature (1000-1200 °C) on SiC samples have been respectively performed under wet and dry air atmosphere for different holding times. The thickness of thermally grown oxide was experimentally measured by DEKTAK Stylus Profilometry. The results showed that the oxidation rate was increased with temperature and holding time, corresponding to a passive oxidation regime which led to the formation of SiO2 layer. The sessile drop method was employed in order to measure the contact angles between Si and SiC at high temperature. Contact angle can be varied from 39.6° to 75.6° by controlling the atmosphere. The deoxidation of the oxide layer and infiltration of liquid silicon caused a decrease in the contact angle.

Jan 1, 2016

By Carlos Maurício. F. Vieira, Lázaro A. Rohen, Sérgio N. Monteiro, Rafael G. de Castro, Gustavo X. Borges, Maycon A. Gomes, Frederico M. Margem, Anna C. C. Neves

Economic and environmental benefits are motivating studies on natural fibers, especially lignocellulosic extracted from plants, have been studied to substitute synthetic fibers, such as glass fiber as reinforcement in polymer matrices. By contrast to synthetic fibers, natural fibers have the disadvantage of being heterogeneous in their dimensions specially the diameter. About the hemp fiber, little is known of their dimensional characteristics. The aim of the present work was to statistically characterize the distribution of the diameter of hemp fibers. Based on this characterization, diameter intervals were set and the dependence of the tensile strength of theses fibers with a corresponding diameter was analyzed by the Weibull method. The diameter was measured with precision using a profile projector. Tensile tests were conducted on each fiber obtain mechanical strength. The results interpreted by Weibull statistical showed a correlation between the resistances of the fiber to its diameter.

Jan 1, 2015

By Antoine Allanore, Guillaume Lambotte, Bradley R. Nakanishi

Current industrial methods used for rare earth element (REE) extraction involve: 1) ore enrichment, 2) separation of rare earth oxides (REOs), 3) chlorination or hydrofluorination, and 4) individual electrowinning of REEs from a molten halide electrolyte. The complexity of REE extraction is inherited from their electronic configuration. Recently, molten oxide electrolysis (MOE) has been used to produce reactive metals directly from their oxides, e.g. titanium. As a single-step alternative to processes 3) and 4), or laboratory has investigated rare earth extraction by MOE. A key challenge is to find a molten electrolyte more stable than REOs. One possibility is to use binaries of REOs directly as a solvent. We have, therefore, developed two experimental approaches for studying molten REOs at temperatures exceeding 2200oC. The present work reports the most recent experimental results obtained with La2O3-Y2O3. Those promising results demonstrate potential for operating with molten REOs and refine the underlying materials challenge for electrodes to enable metal recovery.

Jan 1, 2015

By Chen Song

In the experiments of purifying the solution of chlorine leaching from nickel concentrate with N235, the effects of organic phase composition on purifying efficiency have been studied. From the results obtained, the optimal organic phase composition is found to be 25%N235+12%isomerous alcohol +63%sulfonic kerosene (VIV) and the saturated content of cobalt in organic phase is7.95 g*dm3. And then the serial experiment is carried out. The results show that at the given organic phase composition, the purified solution contains p(Ni) >200 gm dm3, p(Ni)l p(Co) >50000 and the contents of Cu, Fe, Mn, Zn meet the technical criterion of standard nickel electrolyte. The cobalt chloride solution contains p(Co) >I10 g L-1, p(Co) lp(Ni)>50000 and the enrichment of cobalt has been achieved.

Jan 1, 2006

By Yanhui Liu, Xuewei Lv, Pingsheng Lai, Chenguang Bai

The purpose of this paper is to study the effect of slag basicity on the Si content in stainless steel master alloys prepared by smelting reduction of Fe-Ni-Cr sinters. Theoretical analysis focusing on the gas, slag and alloy phases of the smelting reduction process at 1600°C was carried out by thermodynamic calculation software----FactSage, showing that the increase of CaO within the slag can result in the decrease of Si within the master alloy. Experiments were also carried out in vacuum melting furnace at 1600°C , and chemical analysis method was used to detect Si content in the alloys. When the MgO content is 9.00%, the experimental results were consistent with the calculated values. However, when the MgO content rises up to 14%, the content of Si in the alloy reaches the maximum when SiO2 equals to 22.81%.

Jan 1, 2016

By L. A. Harris

The formation of coke during coal liquefaction can eventually result in catastrophic failure of the conversion system. Coking typically proceeds by the formation of liquid crystals (mesophase) and the subsequent separation of these crystals from the plastic phase formed during heating of coal. The anisotropy of the mesophase makes it readily detectable in the optical microscope under polarized light. This study examines the solids formed during coal liquefaction processing by optical and electron microscopy. Observations on the relationships between the coke morphology, minerals and inert macerals are presented.

Jan 1, 1982

By Fan Xiao-Hui, Jiang Li-Juan, Chen Xu-Ling

"In order to solve air leakage of sintering testing cumbersome, inaccurate results, and other issues, the sinter machine air leakage characteristics were studied, and combining the mathematical modeling and the field detection. The temperature before air leakage was calculated by mathematical model, energy balance equation was established according to sintering process, using Adams prediction correction method which has stronge stability and high precision, to solve hyperbolic partial differential equation with astringency problem. The temperature after air leakage is detected by instruments, according to energy conservation calculation the sintering air leakage rate. According to the sintering continuity and periodicity, sintering air leakage location diagnosis expert system was established to judge specific air leakage locations.IntroductionStrengthening of modern blast furnace production depends on the quality of the raw material preparation to a large extent [1]. Technical and economic index of modern blast furnace production is advanced; the most important reason is the use of concentrated feed. Sintering plant is the ""kitchen"" of blast furnace’s concentrate. As we all know, sintering plant is major energy consumption of steel plant, in sinter process energy consumption, the solid fuel consumption of total energy consumption is 75%~80%, power is 13%~20%, ignition and combustion is 5%~10%. To reduce the air leakage of sintering plant is an effective measurement to save energy consumption. At present, our air leakage of sintering compared to the other developed countries is still a long way to go. Japan’s air leakage rate is about 30%, and 35%~60% air leakage of sintering machine at home, a big gap exists between the plants. At present the determination of air leakage is all for manual operation, long measuring period, considerable manpower and resources, and the results are significantly affected by operation. For air leakage of sintering control lag issues, research and development of diagnosis expert system for on-line monitoring model for air leakage and, through this research can reduce the use of detection equipment, detect sintering air leakage, improve the yield and quality of sintering production, reduce energy consumption, and extend equipment life span."

Jan 1, 2012