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By Shenghui Guo, Ying Lei, Wei Li, Jinhui Peng, Libo Zhang, Yu Li

"In this work, the Panzhihua low grade ilmenite and graphite were milled for 1, 2, 4 and 8 h firstly, then the temperature rising behavior of milled sample in microwave field were studied. The average heating rate of samples milled for 1, 2, 4, 8 h were 1.86, 4.08, 2.82, and 2.32 K/s; Before optimize the microwave reduction process, several experiments were conducted in order to confirm the parameters range. After milled for 4 or 8 h and reduced above 930 oC, the Fe metallization are higher than 90%; Then the optimization was investigated by using response surface methodology (RSM), the significance of predict model and each terms were analyzed, and the optimization parameters were given as: milling time is 4 h; reduction temperature is 1001 or 1070oC; the holding time is 37.5 or 26.9 min. Under these conditions, the Fe metallization given by predict model is 91 or 92 %.IntroductionThere is about 9.66 billion tons of Vanadic Titan-magnetite deposits in Panzhihua, China. In this reserve, there is about 8.73×108 t of TiO2, accounting for 90.54% of the Chinese reserves, and 35.17% of the international reserves and ranking first in the world. [1] Titanium mineral deposits are classified into Rock type and Placer type. Rock type is the igneous mineral, which have high content of FeO (Relative to Fe2O3) and gangue. The Panzhihua ilmenite is a typical rock type ilmenite ore. The higher contents of MgO, CaO, SiO2 and the complex mineralogy are making its direct reduction progressively more difficult."

Jan 1, 2011

By Adolf Mikula

Lead-tin solders are commonly used in electronic packaging due to their unique combination of electrical, chemical, physical, thermal and mechanical properties. Since it is known that lead and lead containing alloys cause great environmental concern and health hazards it is necessary to replace lead in solder materials. Besides the environmental concerns new technologies in electronic packaging require new and improved solders. In most cases the new solders will consist of ternary or quarternary alloy systems, the main component will be tin or indium and the second element could be bismuth, silver, copper and gold and to improve certain properties a third element will be added. For a third element zinc, nickel, antimony and aluminum can be considered. This report will concentrate on solders containing zinc as an environmental safe element.

Jan 1, 2003

By M. Opler

Presently, only a few large copper refineries are able to produce Grade A cathodes from copper scrap. Today's technology needs large plants for smelting, converting or refining the main impurities and casting the anodes for electrolytic refining. A new ECUPREX® PROCESS, by-passes all pyrometallurgical operations and produces directly copper cathodes starting from copper scrap with high lead and tin contamination. Copper scrap from chopped cables, copper cements and electronic scrap are suitable feed for ECUPREX® PROCESS. This process uses a non-conventional electrolyte and produces a surprisingly high quality, smooth cathode assaying only few ppms of total metallic impurities. Bench-scale work followed by a successful mini-pilot plant run, has led to the construction of an operating pilot plant equipped with a 1,000 Ampere cell. The results of the operations of this pilot plant are presented and described in this paper.

Jan 1, 1995

By D. E. Roberts

Over 425 million used automotive oil filters are discarded in the United States each year. Estimates prior to this research claim that 10% are recycled with the remainder typically being landfillcd. Surveys conducted with ferrous scrap users and oil filter processors as part of this research reveal that at least 15% are currently being recycled as ferrous scrap. Oil filter scrap is not being used by many operations because of concerns with scrap consistency and quality. These concerns stem from trials conducted in the infancy of the oil filter recycling movement. Consistent scrap quality depends both on the content of the used oil filters and the processing technique used to produce the scrap. Technology has advanced since the first recycling trials were conducted by steelmakers. Several different types of scrap are available, including pucks, bricks, cubes, and shred. This research conducted at the University of Missouri-Rolla investigated the content of used oil filters and compares the recyclability of different oil filter sizes and designs. Filters vary by application and vary between manufacturers for a particular application. An understanding of the scrap itself as well as the concerns and problems of both oil filter recyclers and oil filter processors is necessary to increase the number of used oil filters being recycled.

Jan 1, 1996

By Mikula Adolf

Lead-tin solders are commonly used in electronic packaging due to their unique combination of electrical, chemical, physical, thermal and mechanical properties. Since it is known that lead and lead containing alloys cause great environmental concern and health hazards it is necessary to replace lead in solder materials. Besides the environmental concerns new technologies in electronic packaging require new and improved solders. In most cases the new solders will consist of temary or quarternary alloy systems, the main component will be tin or indium and the second element could be bismuth. silver, copper and gold and to improve certain properties a third element will be added. For a third element zinc, nickel, antimony and aluminum can be considered. This report will concentrate on solders containing zinc as an environmental safe. element.

Jan 1, 2003

By Paula Ana Paiva

The high economic value and unique technological properties of the platinum-group metals (PGMs), plus their growing scarcity in the Earth’s crust, justify the crucial importance of developing recycling practices for PGMs end-of-life materials. Examples of top devices relying on the use of PGMs are automotive and industrial catalysts, and electrical and electronics equipment. This article critically describes the most recent research on the use of solvent extraction to recover one PGM, palladium, from spent catalysts. Some groups focus on the development of schemes involving commercial extractants, while others prefer to design specific molecules to efficiently and selectively recover palladium from these particular complex leaching solutions. Examples of commercial extractants proposed for the former schemes are Alamine® 308, TBP and LIX® 84I; while on the other hand, sulfur-containing diamides, thioamides, thiocarbamates, and dithioethers have recently been developed. Ionic liquids have to be mentioned too.

By G. N. Shannon

Keywords: inclusions, slag, modeling, interfacial energy, capillary force, particle flotation, particle separation A previously introduced model of inclusions separating across a steel-slag interface, developed by Nakajima/Okamura and Bouris/Bergeles, is expanded to include different inclusions shapes (octahedral and plate-like, besides spherical) as well as comparison between model ladle-, tundish-, and mold-slags. Investigation of the relation of these shapes with the interfacial capillary force ? which arises due to the dynamic interfacial energy during separation ? has shown that the force has a significant effect on whether the inclusion separates rapidly or settles at the interface. For the slags considered, the most significant physical property is found to be viscosity, which resulted in fast separation times for inclusions in the mold and ladle slags, relative to the more viscous tundish slag. Particle dissolution (using experimental data) is included in separation modeling.

Jan 1, 2005

By Yafei Xiong, Yue Wang, Guotao Xu, Shuzhong Li, Huaiyuan Li

"The composition, properties and structure of taphole clay with high strength and friendly surrounding used in a new blast furnace with 3800 M3 volume was studied. The developed taphole clay had been applied in the blast furnace for four months, pouring times were 11-13 every day, flowing rate of hot iron was 7.5 t/min and the consumption of taphole clay was 0.49Kg per ton iron, which can make the new blast furnace attach the designed production quickly and decrease the cost of hot iron. The taphole clay is easy to be opened in the channel of hot iron which can be remained in stable shape under the corrosion of slag or hot iron, and it dose not produce poisonous smoke in yellow or dark color in the use process. The development of new taphole clay is useful to improve the work surrounding of the blast furnace.IntroductionIn the iron-making process, the taphole clay's function is filling up the taphole and protecting the formation as well as the growth of the clay in the blast furnace, maintaining the enough taphole depth; simultaneously it is easily to open a hole and knock out the clay. The taphole clay has a good performance of molten slag and hot iron resistance. The traditional taphole clay uses coal tar or carbolineum as a binder, and the performance of taphole clay is good, but it has the black and yellow poisonous smoke, which is harmful for work condition. Through the investigation on the binder's composition and poisonous performance of taphole clay, the environmental taphole clay is developed by some foreign companies, which is named the third generation product with benzene is less than 300ppm, and it has been used in European steel companies. This application of the taphole clay with high strength and environment-friendly using in 3800m3 blast furnace is introduced and the performance is discussed and analyzed in this paper."

Jan 1, 2012

By María Eugenia Castro, Silvia Galasso, Jorge Duca, Claudia Osuna, Ernesto Esparza

"We present a procedure for treatment of non-active solutions equivalent to the solutions obtained from dissolution of ionic exchange resins used in purification of a nuclear reactor primary cooling system containing Co, Ni, Cs and its isotropic varieties as main radioactivity source. Finally it is immobilized into a ferritic matrix by calcination which avoids its future leaching into environment.In order to achieve the objective of this treatment, a bivalent and a trivalent iron salt is added to the solution. Then, either a base or an acid is added, depending on the initial pH of the treated solution, with a Cs precipitating additive in order to reduce Co and Cs by precipitation, flocculation and adsorption. Controlling the amount of precipitating reactives it is possible to modify the activity/volume rate becoming a medium into a low radioactivity waste.The leaching test result applied over the ferritic sample is lower than the minimum limit established by law. Therefore, it can be kept safely in a interim storage."

Jan 1, 2008

By Sutham Niyomwas

Silicon-Silicon Carbide (Si-SiC) composites were synthesized by self-propagating high temperature synthesis (SHS) from a powder mixture of SiO2-C-Mg. The reaction was carried out in a SHS reactor under static argon gas at a pressure of 0.5 MPa. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The effects of silica sources and carbon mole ratio in precursor mixture on the Si-SiC conversion were investigated using X-ray diffraction and scanning electron microscope technique. The as-synthesized products of Si-SiC-MgO powders were leached with 0.1M HCl acid solution to obtain the Si-SiC composite powders.

Jan 1, 2009

By B. Mishra

Several reactive metal purification processes using molten salts generate effluent from which significant quantities of metal can be recovered prior to discardinglrecycling the salt. A Salt-scrub [SS] process has been applied where the reactive metals are recovered as a metal-gallium alloy by calciothermic reduction of the metal compounds. The SS alloy compositions were produced by mixing, pressing and sintering the metal-powders. Measurement of metal recovery has been studied for cerium, silver, tin and lead. The process has been optimized for variables such as the metal quantity per kg of effluent salt, amount of excess calcium over stoichiometry, stirring rate and time and holding time at reduction temperature. Over ninety-seven percent metal recovery has been obtained under optimized conditions. The development of an alloy for efficient Salt Scrub processing reduces a major contaminated waste disposal problem as well as recovering the valuable reactive metal. Surrogate metals have been used in this work to study the behavior of plutonium.

Jan 1, 1994

By S. Y. Tan

The thermal stability of fully silicided NiSi with arsenic doping on silicon was investigated. The aims of the work were to investigate the Ni silicide phase-related issues associated with arsenic dopant and thermal annealing on Ni-FUSI/HfO2/Si and Ni-FUSI/HfSiO/Si gate stacks. It was found that arsenic-incorporation demonstrated some improvement in both morphology and phase stability of nickel silicided films at high processing temperatures regardless underlying gate dielectrics. The correlations of Ni-Si phase transformation and arsenic doapnt with their electrical and physical changes were established by sheet resistance measurements, X-ray diffraction (XRD), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) analysis. Furthermore, the modulation of the work function (WF) of Ni fully silicided gates by arsenic impurity is presented, comparing the effects of dopant (As) on the WF and silicide phases (NiSi and NiSi2). It confirmed that the work function of NiSi can be tuned by implanting arsenic dopant, but it ineffective for NiSi2 phase.

Jan 1, 2010

By J. A. Holmes

Due to varying and complex mineralogy, the flotation tailings from the Chingola Concentrator have, for some years, contained upwards of 0.4% acid soluble copper. In 1968, an investigation was initiated, to determine a method for recovering this acid soluble copper. This initial investigation concluded with a recommendation to install a leach-solvent extraction-electrowinning plant at Chingola, to treat up to 900 000 tonnes of material per month, for an additional copper production of some 4 500 tonnes per month. The process consists basically of six stages :- Materials reclamation handling and preparation, acid leaching in air agitated pachucas, solid-liquid separation by countercurrent washing in thickeners, solution concentration and purification by solvent extraction, copper recovery by electrowinning, and residue neutralisation and disposal. This paper describes the development of the main parameters for design of each of the six sections, and gives details of the final plant design. Problems encountered in commissioning and initial operations are commented on, particularly insofar as they indicated any errors or misjudgements in the design. The choice of materials of construction is commented on in some detail.

Jan 1, 1976

By Z. Zhang, R. G. Reddy

The viscosities of industrial lead slags with various compositions were measured as a function of temperature. It was found that viscosities of lead slags decreased with increasing temperature, and the plots of ln(11) vs. 104tr followed a linear relation over the reported ranges of temperature. Using the data of this study and available other related data from the literature, a viscosity expression was developed as a function of composition and temperature. The calculated results using this viscosity expression are in good agreement with the measured data. The composition dependency of viscosity of lead slags is discussed.

Jan 1, 2000

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 N. A. Warner

Fundamental studies on the reaction of limestone or dolomite at high temperature with S02 are extended to the realm of large scale primary copper smelting. Whereas flue gas desulfurisation in the electric power utility industry is concerned with S02 concentrations normally less than 0.5 percent, high temperature smelting gases can have S02 levels approaching 100 percent. The reaction involved is very exothermic so proposals are made in this paper for returning the heat generated in sulfur fixation directly back to the copper smelting process. This integration leads to metal production with lower energy requirements than current technology. The anhydrite reaction product can either be disposed of locally with minimum adverse environmental impact or upgraded to a value-added product. It is assumed, of course, that no viable market exists to support sulfuric acid production.

Jan 1, 1996

By Xingjian Gao

The mechanical properties of a low carbon low alloy steel in the austenite and _-ferrite regions have been examined by thermal-tensile tests using a Gleeble-1500D system at temperatures in the range 600oC to 1300oC and at a strain rate of 10-3/s; these being the conditions that apply to the unbending operation during the continuous casting of steel. The yield strength and tensile strength of steel decreased with increasing test temperature and the embrittlement zone occurred in the temperature range 800oC to 970oC. In the embrittlement zone, the fracture surfaces and microstructures of the tensile specimens were examined by scanning electron microscope. The results showed that the cause of the embrittlement at 950oC in which the minimum %R of A was around 36% is the second phase particles precipitated along the _ grain boundary during deformation leading to inter-granular brittle fracture.

Jan 1, 2010

By Xuan Li

Aluminum slag is generated when aluminum metals are recycled through a smelting process in the presence of salt. There are small amounts of aluminum metals trapped in the aluminum slag. This research aims at evaluating the use of aluminum slag as an expansion agent for the production of lightweight concrete by taking advantage of the residual aluminum metals in the slag. The research identified key elements of producing lightweight concrete products through utilizing various mixture components including sodium hydroxide (NaOH), lime (CaO), cement, and gypsum. The volumetric expansion rate was investigated and the density and strength of the products were determined. The results show that aluminum slag can be utilized for the production of lightweight concrete products.

Jan 1, 2010

By T. K. Bundtzen

Placer gold in the Iditarod and Innoko mining camps of western Alaska is derived from a suite of comagmatic, Late Cretaceous to Early Tertiary, alkali-calcic, meta-aluminous. volcanic-plutonic complexes and peralumi-nous rhyolite sills that intrude Mesozoic flysch. Heavy-mineral concentrates from 42 mining operations and streams draining known mineralized areas in the igneous complexes contain placer gold and a variety of ore minerals derived from epithermal to hypothermal conditions of formation. The minerals include cassiterite, ilmenorutile, samarskite, cinnabar, scheelite, chromite, stibnite, silver sulfosalts, monazite, and zircon. Results of the study show that 1) cinnabar. stibnite, and quartz formed with the bulk of the placer gold in an epithermal lode environment, 2) chromite appears to have originated in mafic phases of monzonite plutons and alkalic basalts, and 3) niobium-tin-tungsten-uranium-silver values may have been derived from stockwork accumulations in cupolas of monzonite plutons.

Jan 1, 1987

By Albert Wraith, Thomas Price, Wayne Boyd, Skip (I. E. ) Hills, Cameron Harris

Most Peirce-Smith converters inject air through tuyeres, with nitrogen representing the majority of gas passing through the process. The nitrogen controls the temperature of the vessel by carrying away heat from the reactions, both globally and locally at the tuyere tip. However, nitrogen adds energy to the bath and contributes to splashing and limits the blowing rate. High oxygen smelting has made streams of gas containing high concentrations of sulphur dioxide commonplace, which can be used to substitute SO2 for nitrogen and drastically changes Peirce- Smith converting (and all other smelting/converting processes as well). Less SO2 is required to carry away the same quantity of heat, which allows higher concentrations of oxygen and leads to the possibility of increased production. The paper investigates this substitution, its impact on converter productivity, and on the remainder of the plant. 181

Jan 1, 2009