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By C. H. Tsau

The intermetallic compounds of Ni-25Al-xFe, x is 20-40 at.%, were prepared by arc melting and drop casting into ingots, and were rapidly solidified into ribbons by melt spinning. The microstructure evolution of these alloys with varied Fe content were examined by the x-ray diffraction, optical microscope, scanning electron microscopy and transmission electron microscopy. The results reveal that two phases, {y'} and {B} phases, are existing in the alloys with low Fe content, and the microstructure changes from the mixture of y' and {B} phases to a single 0' phase when the Fe-content reaches to 40 at.%. Also, the formation of y' phase will be suppressed by rapidly solidified process. For annealing both of the melt-spun and the cast specimens, a disorder 0 phase was revealed in both of the ribbon and the cast ingot of Ni-Al-Fe alloys with higher Fe content. In addition, increasing the increment of iron which substituting nickel in this alloys results in increasing the lattice parameter of both {y'} and{B} phases.

Jan 1, 1992

By F. J. Hogan

In early 1982 Atlantic Cement Company, a wholly-owned subsidiary of Newmont Mining Corp. will come on line with a new water granulating grinding facility at Sparrows Point, Maryland to produce 800, 000 tons a year of separately ground granulated blast-furnace slag. The process and product will be unique to the United States. This paper will review some initial investigations undertaken to evaluate the cementitious properties of granulated slag. The effect of slag fineness on strength development is discussed and data is presented showing a relationship between glass content and hydraulicity and grindability of slag.

Jan 1, 1982

By Terry Mandziak

Typical leach mine operations recover gold values through the application of a dilute cyanide solution onto ore within an engineered facility. Key to the success of mining operations is the, containment and management of the cyanide solutions within the facility. Properly engineered' facilities will have containment systems that are both protective of the environment while enhancing solution recovery. This paper not only discusses general containment standards, but identifies state-of-the-art containment and monitoring practices;

Jan 1, 1998

By George H. Edwards

Most cullets consumed in large-volume glass manufacturing processes receive little processing beyond crushing. But lead-glass cullets for specialty glasses such as industrial lighting refractors or cathode-ray tubes are combined with metals and various coatings that prohibit their direct recycling into the glass-melting processes that created them. In many cases, the contained lead renders these cullets hazardous. At present, virtually all industrial processes to separate one cullet from another depend on hand sorting, and thus are necessarily costly per unit weight. Lead-glass cullets of differing lead content are of interest because they offer the possibility of separating one glass composition from another by high-speed, automated processes at low cost. A potential process for comminution, cleaning, and separation of lead-glass cullets would involve primary and secondary crushing, magnetic and other metals separation, attrition scrubbing in water, separation of glass types by gravity techniques, drying if necessary, sampling, and preparation for transport to the point of use. Process water would be filtered to remove finely divided coating materials and glass, and reused. If carried out on a scale similar to a specialty industrial mineral processing plant, the cost per unit weight of such processing should be substantially less than the raw material value of the cullet in specialty glass production. The added value of avoiding waste disposal costs makes this process economically attractive.

Jan 1, 1994

By Ilona Johnson

United States metals and non-metallic minerals manufacturing consume about 5,000 trillion Btu annually. Various studies estimate that as much as 20 to 50 percent of this energy is lost as excess or waste heat. Recovery of waste heat can conserve energy, reduce operating costs, and lower environmental emissions. It would be valuable to quantify recoverable waste heat sources and identify the barriers that hinder its recovery. This paper provides an overview of waste heat losses specific to high temperature processes in primary metals and minerals manufacturing. It summarizes findings from a broader study conducted for the Department of Energy Industrial Technologies Program; the study evaluates energy losses, recovery practices and opportunities, and R & D needs for waste heat technology development.

Jan 1, 2008

By Chen Dong, Yuanling Gao, Jilai Xue, Jun Zhu, Luxing Feng

"Porous Ni-Ti alloy has many applications in a wide range of engineering areas. The porous NiTi alloys were prepared from Ti and Ni powders in sintering process under argon atmosphere. The major chemical compositions of the sintered Ni-Ti body were Ni Ti, Nh Ti4O and Nh Ti, respectively, the internal pore structures were characterized by image analysis technique, which were dependent on various processing parameters such as sintering temperature, amount of poreforming agent, forming pressure, etc. The results show that the porous alloy samples had the characteristics of uniform pore and high open porosity; pore-forming agent and sintering temperature are important factors in porous; pressure affected the sintered products' pore, by affecting the combination of alloy powder with pore-forming agent.IntroductionPorous Ni-Ti alloy materials exhibit not only excellent shape-memory and superelasticity, high yield strength and ductility, good corrosion resistance and biocompatibility, but also have low density, low stiffness, and high energy absorption rate due to their porous structures [1]. In recent years, these porous Ni-Ti alloys have found applications in a wide range of engineering areas, such as bone implants [2-4], impedance-matching connectors [5], energy-absorbing structures [6,7], separators [8] and actuators [9], etc.Pore characteristics can play very important role in determining of the performance of porous NiTi alloys. For example, when the alloys are used to repair or replace hard tissue implant material, the pore shape and size not only determine their mechanical properties, but also have great effect on the fluid transmission of human body. The pore characteristics can also influence the stressstrain behavior of the porous Ni-Ti alloy and, thus, strongly affect their mechanical properties, superelasticity, and fracture mechanisms [10].In this study, the Ni-Ti alloys with high porosity were prepared in a powder sintering process under argon gas. The pore characteristics were investigated using SEM, XRD and image analysis techniques, especially in association with the content of pore-forming agent, sintering temperature and compacting pressure."

Jan 1, 2011

By Virgil Optasanu, Yvon Lacroute, Eric Lesniewska, Tony Montessin, Pauline Vitry, Eric Bourillot, Cédric Plassard

A general challenge in metallic components is the need for materials research to improve the service lifetime of the structural tanks or tubes subjected to harsh environments or the storage medium for the products. One major problem is the formation of lightest chemical elements bubbles or different chemical association, which can have a significant impact on the mechanical properties and structural stability of materials. The high migration mobility of these light chemical elements in solids presents a challenge for experimental characterization. Here, we present work relating to an original non-destructive, with high spatial resolution, tomographic technique based on Scanning Microwave Microscopy (SMM), which is used to visualize in-depth chemical composition of solid solution of a light chemical element in a metal. The experiments showed the capacity of SMM to detect volume. Measurements realized at different frequencies give access to a tomographic study of the sample.

Jan 1, 2015

By Lei Zhang, Shining Chen, Lina Wang, Pu Liu, Benquan Fu, Jiannyang Hwang

A PFS(polymeric ferric sulfate) coagulation-photocatalytic oxidation technology was used for advanced treatment of coking wastewater from secondary biological treatment. Effects of some key factors on TOC removal rate were investigated, and the results were compared with those of the common photocatalytic oxidation technology under the operating parameters of the photocatalytic oxidation defined. Single factor experimental results showed that TOC removal rate could reach 81%, when optimal operating conditions were as follows: TiO2 loading: 4.0g/L, irradiation time: 4h, initial pH is 5.1and PFS dosage:700mg/L. PFS coagulation and photocatalytic oxidation have synergistic effect, which is meaningful for highly efficient treatment of coking wastewater

Jan 1, 2015

By Hyun Soo Kim, Joon Soo Kim, Myong Jun Kim, Jyothi Rajesh Kumar, Jin-Young Lee

Rare earth materials have an ever growing variety of applications in the modern and hitech technology. They apply to many an industry with crucial materials and they provide numerous a customers with benefits. Rare earth materials utilization increasing day-by-day in the worldwide, at the same time the resources is very limited in many countries like Korea. The present general article divided four sorts such as 1) mineral processing of Korean ore deals the gravity, magnetic separation and froth flotation, 2) decomposition and leaching of concentrates included sodium hydroxide fritting, sodium hydroxide hot digestion, hydrochloric acid leaching, 3) separation and purification of rare earth elements in mixed rare earth chloride solution consists reduction and oxidation method, solvent extraction, 4) preparation of rare earth oxide compound from purified elemental rare earth chloride solution having oxalate salt precipitation by reaction crystallization. The last part consists of a summary of the present study.

Jan 1, 2015

By Kai Kang, Jun Bao, Shouping Liu, Xiao Sun

Powder characteristics have a significant influence on selective laser melting (SLM) process. In this research, particle size, surface contour and the microstructure of IN718 powder used in SLM were tested, and the physical and chemical changes during heating process of the powder were investigated as well. The shape characteristic and fluid properties of IN718 powder were defined and measured. It is shows that most particles of IN718 powder exhibited nearly spherical shapes, and the particle size is about 22.95μm. On this basis, IN718 sample was fabricated by SLM process using the powder and the microstructure of the fabricated sample was investigated. The results indicated that the sample has a dense microstructure, no macro-defects but a few micropores and porosity. Compared with the powder, there was no new phase formed in the sample and melting point of the sample was little less than that of the powder.

Jan 1, 2015

By S. Redik, C. Wenzl, D. Gregurek, A. Spanring

Zinc is a component of many input materials used in various pyrometallurgical processes, for example primary lead and zinc production from Pb/Zn ores and recycling processes dealing with zinc-containing residues (e.g., copper recycling, WAELZ process). Hence, zinc and its compounds are present in the respective metallurgical vessels and interact with the refractory lining. In the present work the zinc attack on the refractories out of various primary and secondary furnaces is briefly introduced and discussed. At the prevailing processing temperatures in the metallurgical vessels, zinc oxide is highly corrosive for the brick components. The knowledge of the wear behavior is based not only on a detailed chemical and mineralogical characterization carried out on provided post mortem samples, but also on FactSage calculations. This together with results obtained by practical testing in the RHI pilot plant represents an important prerequisite for product development and brick selection for the individual customer application.

Jan 1, 2016

By Zhenyang Wang, Yiran LIU, Xiangdong Xing, Jianliang Zhang, Zhengjian Liu

Basic characteristics of marine placer were systematically studied by chemical analyze, scanning electron microscope and X-ray diffraction in this paper. It could be found that the marine placer mainly consists of titanomagnetite and titanohematite. A series of experiments were performed to investigate reduction-magnetic separation for Fe and Ti from the marine placer. Effects of reduction temperature, reduction time, carbon ratio, magnetic density, and grinding fineness on the reduction-magnetic separation process were investigated. And the optimal process parameters were obtained as follows: the reduction temperature 1300, the reduction time 30 min, the carbon ratio 1.1, the magnetic density 50mT, and the grinding fineness of 0.074μm 86.34%. Under such conditions, the metallization rate, iron grade of magnetic substance and iron recovery reached to 94.23%, 97.19% and 90.28% respectively, and the titanium grade in non-magnetic substance and recovery of was 57.94% and 87.22% respectively. The effective separation of iron and titanium could be achieved in reduction-magnetic separation process.

Jan 1, 2015

By R. W. Smith

The flotation response and electrokinetic behavior of Chlorella vulgaris and Chlamydomonas sp . when using dodecylamine hydrochloride as collector were studied in the absence and presence of Pb(I1). Also, an electron microscopy study was made of the algae after Pb accumulation. The flotation behavior of the organisms after Pb accumulation appears at least partially related to the location of the abstracted Pb onto or into the organisms.

Jan 1, 1991

By R. Padilla, M. C. Ruiz, R. Villa

"Bismuth is an impurity in copper minerals where it occurs mainly as the mineral bismuthinite (Bi2S3). In smelting of copper minerals, most of the bismuth reports to the white metal, as a result, a substantial amount of bismuth accompanies the copper to the electrorefined cathodes. Thus understanding the behavior of Bi2S3 at high temperatures is crucial to eliminate bismuth before electrorefining. In this paper, some experimental data on the decomposition/volatilization of bismuthinite in nitrogen- oxygen atmospheres is discussed. The results indicated that in nitrogen atmosphere, bismuth volatilization occurs through a fast decomposition of bismuthinite to metallic bismuth and sulfur with subsequent volatilization of bismuth in the range 850-1100 °C. Similarly, in the presence of oxygen, bismuthinite decomposes to bismuth too, followed by oxidation to the non-volatile bismuth trioxide at temperatures higher than 750 °C. Both, temperature and partial pressure of oxygen affect significantly the bismuth volatilization and the oxidation rates.IntroductionCopper sulfide minerals are the major source for the production of metallic copper by pyrometallurgical processes, which are the dominant processes in the production of copper by selectively oxidizing the sulfide sulfur to SO2 and the accompanying iron in the concentrates to iron oxide, which can be conveniently removed as a stable slag.Generally, copper concentrates contain some deleterious minor elements such as arsenic, antimony, bismuth and lead, which are present as sulfides. These elements depending on their concentration may originate problems in the copper smelting processes and they can ultimately lead to a final copper product with unacceptable high levels of impurities.During the treatment of these copper concentrates by smelting, the impurities generally distribute themselves in the condensed and gas phases and they are eliminated mainly through the gas phase [1-3]. Thus, smelter off gases contains substantial amounts of volatilized impurity elements. For example, in the case of bismuth, the estimated distribution of bismuth in flash furnace smelting [2] was 15 % in the matte, 5 % in the slag and 80 % in the gas phase, and recently, for Outokumpu flash smelting Davenport [3] reported the distribution of bismuth as 30-75% in matte, 5-30% in slag and 15 -65 % in the off gas."

Jan 1, 2011

By Olli Hyvärinen

The capacity of Outokumpu Pori Copper Refinery has been increased by 50 % to 70 000 t/a in the last five years by adopting periodic current reversal, reducing spacing and installing some new cells in the old tank house building. Five years operation of PCR has proved that it is possible to achieve additional capacity with PCR and yet produce high quality cathodes. The impurity level in anodes has considerably increased, and recently, arsenic, antimony and sometimes bismuth have displaced nickel as the most critical impurity.

Jan 1, 1987

By Charles Zimmerman

The Genesis gold mine, owned and operated by Newmont Gold Co., is located in section 31, T36N, R50E within Eureka County, Nevada along the Carlin Trend of sediment-hosted disseminated gold deposits. Mining commenced in 1986 with present mineable and stockpiled reserves listed at 17,711,000 tons of ore averaging 0.073 opt Au, totalling 1.292 million ounces of gold. Ore is primarily hosted within Devonian calcareous siltstones that have been subjected to intensive argillization and silicification episodes. Additional mineralogic and geochemical features of the Genesis ores include enrichment in iron-oxides, kaolinite, arsenic and antimony; the ore zone is relatively depleted in carbonates and sulfides as a result of supergene and hypogene oxidation. Two major structural zones enhanced the permeability of the siltstones and served as the main hydrothermal conduits within the deposit. Prior to the main ore stage, the host rocks were subjected to metasomatic effects caused by emplacement of the Juro-Cretaceous Goldstrike granodiorite pluton and associated dikes and sills. Micron-size gold occurs in clays, micro-crystalline quartz, and in arsenical complexes. Non-oxidized carbonaceous and sulfidic ores and silica-locked ores result in variable preg-robbing and refractory responses during cyanide recovery. Selective mining and milling has resulted in the successful treatment of the Genesis orebody.

Jan 1, 1988

By Wantae Kim, Furnia Saito, Qiwu Zhang

"A novel mechanochemical processing technique for the preparation of zeolites from kaolinite in NaOH solution was investigated. Dry and wet mechanochemical treatments combined by subsequent moderate heat treatment could accelerate the synthetic reaction for zeolites from kaolinite. This stimulating process produced zeolite-A and zeolite-X from activated kaolinite at extremely lower reaction temperature than conventionally applied for zeolites production. Conversion to zeolite-A and zeolite-X was strongly dependent on the activated state of kaolinite. Wet mechanochemical treatment modified the chemical composition of activated solids. Rapid dissolution of AIO species rather than SiO ones in the reactant solution was accelerated by wet milling together with NaOH that promoted the formation of zeolite-X of high specific surface area.IntroductionZeolites are a family of hydrated alumina-silicate minerals contains alkali and alkaline earth metals. They have a framework structure that encloses inter-connected cavities occupied by large metal cations and water molecules. Zeolites are characterized for their ability toward ion exchange and reversible dehydration. Properties of them are exploited through commercial productions of particular structural and chemical features. Zeolites are used as commercial uses for catalysis for FCC (fluidized catalytic cracking) of petroleum refining, drying reagents of gases and liquids, and selective adsorbent for pollution control [1-3]. In such purposes, artificially synthesized zeolites are employed, although natural ones are associated with hydrothermal and hot spring alteration of volcanic materials. Commercially, a hydrothermal process has been used for the preparation of zeolite synthesis. This preparation method gives zeolites of high chemical homogeneity and purity, however, this wet-chemistry-based processing is significantly influenced by reaction temperature, pH, concentration, and composition of starting substances [4]."

Jan 1, 2000

By Natasa Mitevska

The statistical analysis of the slag composition influence on copper losses to discard slag in the reverberatory furnaces No.1 and No.2 in the RTB BOR, Copper Smelter and Refinery (Yugoslavia) is presented in this paper. The model for the slag basicity calculation is determined, and connected to the copper distribution coefficients between the matte and slag phase. The influence of all components on the slag structure is also illustrated.

Jan 1, 2003

By Denise C. R. Espinosa

The amount of secondary batteries are increasing about 15% by year. Among these batteries, it can be highlighted the NiCd ones, due to their high consumption. In Brazil, the consumption of NiCd batteries grown quickly in the last 5 years, due to the dissemination of cellular telephones and other electronic devices. The first step of a process to recycle spent NiCd batteries is the pretreatment through unit operations of mining treatment. The aim of this work is to define a physical pretreatment to conditioning the waste to a pyrornetallurgical recycling process of spent NiCd batteries used in cellular telephones. Batteries were disassembled by hand to release the different components. The studied batteries are basically composed (by weight) of: 78% nucleus, 18% plastic case and 2% circuits. The grinding of the batteries was performed by knife mill and also by hammer mill. After grinding the material was screened and submitted to a magnetic separator.

Jan 1, 2001

By WenCai Li, Yong Ren, Shuai Niu, Xin Hong

"Temperature measurement is very important in metal smelting process. Many devices are used to realize non-contact temperature measurements. Compared to conventional thermocouple, infrared temperature measurement has it's unique advantages. However, using an infrared temperature measurement at the top of the furnace can not obtain the desired optical signal because of disturbance from slag layer, high-temperature gases and other effects. A real time thermometry system with dual-wavelength radiation was presented to get optical signal emitted from molten metal through bottom-blowing nozzle. Taking into account the advantages and disadvantages of bottom-blowing devices, a MHP (Multiple Hole Plug) bottom-blowing device was used, through which the optical signal was transferred to the infrared thermometer by use of optical fiber. After conversion and analysis in real-time, the result was displayed and recorded in computer. After calibration, it could be a good predictor of temperature trend in a metallurgical process. IntroductionAt the refining stage of steelmaking, in order to achieve predetermined chemical composition and temperature, high-temperature molten steel is refined in a furnace such as converter. Because the refining process involved with chemical components and reaction velocities in the furnace rely on the temperature of steel, it is necessary to know the temperature accurately in real time during the process. And temperature measurement is also helpful for the end-point judgment. The temperature in the refining process changes quickly, for instance, in a converter, 300t molten steel is processed in only about half an hour.At present, traditional way of temperature measurement is using a thermocouple probe mounted on a lifter called a sub-lance. The thermocouple is immersed in molten steel and its temperature is measured during the short period until the thermocouple is fused. Accurate and reliable temperature can be obtained by this method, but in consideration of the discontinuous measurement and the costs, missing the end-point temperature may sometimes occur.According to the above background, a method in which a temperature-sensing element such as a thermocouple is immersed directly in molten steel is not suitable for the continuous temperature measurement because materials having such stability are not available. Therefore, radiation thermometry is promising. There have been some reports on radiation thermometry through an observation nozzle through the bottom or side of a refining furnace [1, 2]."

Jan 1, 2014