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By Jay S. Gunasekera

Since great emphasis is being placed on the manufacturing science and processing science programs in the Department of Defence and other government research agencies and industries; currently, extensive research on computer aided design(CAD)/ computer aided manufacturing (CAM)/ and computer aided engineering (CAE) is being conducted at Ohio University (OU) . OU has invested over a million dollars in CAD/CAM hardware and software. Design and analysis packages like ALPID, NIKE, STREAM, SHEAR, POLY_FLON, RINGROLL have been developed or modified at OUusing finite element method, finite difference techniques or enhanced slab analysis. Packages like ABAQUS, FLUENT, and NASTRAN have been extensively used.

Jan 1, 1990

By D. Morin

A general study of gold refractory arsenopyrite-pyrite concentrate bioleaching has been carried out including two continuous bioleach testworks at different sizes, namely one at a laboratory scale with a 100 I unit at a 2 kg/d dry solid flowrate and the other at a pilot scale at a 100 kg/d dry solid flowrate. Both tests show a 80% bioleaching of arsenopyrite in about four days of treatment and with the same kinetic. Pyrrhotite is attacked at the earlier stage of the bioleaching but pyrite remains unaffected. The weak potential of oxidation associated with the decomposition of arsenopyrite and the abundance of arsenite leads to a high grade of elemental sulfur in the bioresidue which consumes the major part of the cyanide during the gold recovery. Furthermore. the arsenite and ferrous produced in solution have to be oxidized to obtain a stable precipitate in the waste products and as outlined in previous works of other authors on this subject the addition of iron to obtain a Fe/As molar ratio at least above 3 is necessary. The agitation equipment used in the pilot unit allowed an optimization study calculation for scaling-up the design and power requirements of an industrial installation. For the pretreatment of a gold refractory As high-graded concentrate the reagent cost has the greatest part in the operating cost of the biooxidation step due to the necessary retreatment of the biosolution. In that conditions the power cost is quite marginal. actually it is significant for the treatment of pure pyrite.

Jan 1, 1991

By Muammer Kaya, Sait Kursunoglu

"The aim of this study was to investigate the effectiveness of ascorbic (C6H8O6) / oxalic (C2H2O4) acid as a reductant for the simultaneous recovery of zinc and manganese from a spent and mixed zinc-carbon and alkaline battery powder in sulphuric acid leaching. The effects of sulfuric acid concentration, ascorbic/oxalic acid dosages, reaction temperature and leaching time on the zinc and manganese dissolutions were investigated according to 2k full factorial experimental design; then, a simple optimization study was carried out for the best reductant. The optimum reductive acid leaching conditions were determined at 3 hours leaching time, 70°C leaching temperature, 0.5M sulfuric acid concentration, 13 g/L ascorbic acid dosage, 1/20 g/mL solid/liquid ratio and 200 rpm stirring speed. Under these conditions, the dissolution efficiencies were 99.9% for Zn and 99.3% for Mn. When our results were compared with the previous results, our findings were better than previous studies.In addition, the manganese dissolution kinetics was undertaken, and the activation energy was found to be 7.04 kJ/mol. Selective precipitations of Zn and Mn from acid solutions were carried out using NaOH and KOH. Using 3M NaOH as precipitating agent at room temperature and at pH 8; 95.4% of Zn and at pH 10; 93.7% of Mn were precipitated from the leaching solution. Under the same conditions, using 3 M KOH at pH 8; 91.6% of Zn and at pH 10, 96.4% of Mn were precipitated. Based on the experimental results obtained, an appropriate flow sheet was proposed to recover zinc and manganese."

Jan 1, 2012

By Sayavur Bakhtiyarov

Keywords: Rheology, Viscoelastic, Oil In this paper we present the results of the rheological property measurements on viscoelastic composite materials used in oil industry. Laboratory experiments were carried out to determine important thermophysical, rheological and mechanical properties of the test materials using both the standard commercial and in-house made equipment. The composites with the paramagnetic particles (?-iron oxide) are exhibited a significant magnetic memory after magnetic treatment. The measured value of the yield stress after the magnetic treatment increased almost twice in comparison with the yield stress value of the magnetically untreated composite. The yield stress of the composite material exponentially decreases with time and reaches its magnetically untreated value after 15 hours. The yield stress also increases with the amount of the paramagnetic powder additive, and it reaches a maximum value at 8 wt-% of this additive. The obtained results provide valuable information for computer modeling of the viscoelastic fluid flow in pipes of complex geometry.

Jan 1, 2005

By H. Doostmohammadi

During the tapping of liquid steel from Electric Arc Furnace (EAF), some slag is carried over into the ladle. High levels of FeO and MnO in slag carryover increase the oxygen activity in steel melt leading to oxide inclusion formation during the ladle treatment. The demand on cleaner steels requires minimization of carryover slag. In this work, the effect of EAF slag carryover on ladle slag-steel equilibrium calculations for a hot working tool steel was studied. Steel and slag sampling were done in Uddeholm Tooling AB in Sweden. XRF and OES techniques were used to determine chemical composition of samples. The quantity of slag carryover was calculated based on a mass balance followed by thermodynamic calculations on metal-slag equilibrium using Thermo-Calc software. The agreement between predictions and experimentally determined compositions was good. This leads to the development of a prediction method for optimizing the production of other tool steel grades.

Jan 1, 2009

By Chang-Dong Li

Cadmium ingot and nickel powder were prepared by high-temperature distillation, solvent extraction and liquid phase reducing method with spent Cd-Ni batteries as raw material. The impacts of the temperature in the distilling stage, the concentration of H2SO4 in the leaching stage, the pH value in the extracting stage and the dosage of hydrazine in the reducing stage were discussed respectively. The as- prepared samples were characterized by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic absorption spectrometry (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results showed that the recovering efficiencies of Cd and Ni reach 99.5% and 99.3%, and the purities of Cd ingot and nickel powder were higher than 99.90% and 99.80%, respectively.

Jan 1, 2009

By A. Iván, Patiño C. Francisco, Flores B. Javier, Peréz L. Miguel, Hernandez A. Juan, Trapála P. Norma, Salinas R. Eleazar, Rivera L. Isauro, G. Flores, U. Mizraim

"Tills work is related with the production of tiles using wastes from mining and metallurgical industry of Hidalgo State, as raw material. These wastes present a majority particle size (60 %), minor than 53 m (mesh 270, in Tyler Series) with the following composition; 70.01 % wt. of Si02, 12.82 % wt. of Ah03, 3.80 % wt. of Fe, 0.70 % wt. of Mn, 3.98 % wt. ofK20, 3.34 % wt. of CaO, 2.50 % wt. ofNa20, 0.04 % wt. of Zn, 0.026 % wt. of Pb, 56 grams per ton of Ag and 0.6 grams per ton of Au. In this work, the partial results and experimental conditions for the preparation of some composites to produce tiles are shown. The composite that offers the best results in productions of tiles was that with 66.67 % wt. of mining waste, 26.67 % wt. of red mud and 6.67 % wt. of black mud.IntroductionTo now, mining activities carried out during more than 457 years in Hidalgo State, Mexico; has lead a great volume of wastes; which can be classified into different types, having among the more common; Acid mining water, solid transport water, elements in radical form, abandoned minerals without processing and processing minerals wastes known as burrows, being these the most abundant in the region counting with an approximated volume of 110 million of tons, presenting a fine particle size that can affect population health during windy epochs [1 -4].Form metallurgical point of view, is well known that a fundamental characterization study it is necessary to know the viability of reusing or recycling of these wastes. According this, these residues can also be considered as raw materials in other economical activities, due its Si, Fe, AI, Ca, Na and P oxides contents, its mineralogy and the distribution of chemical elements in the primary and secondary phases [1,2,5,6]."

Jan 1, 2012

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

By Purushottam Kumar

Keywords: Magnetostriction, magnetic properties, Pd(Fe,Co,Ni) single crystals Fe-Pd, Co-Pd and Ni-Pd alloy systems show appreciable magnetostrictive strains that are of interest for sensor applications. These systems exhibit congruent melting minima. In this work the magnetic and magnetostrictive behavior of congruent melting Fe-Pd, Co-Pd, and Ni-Pd compositions have been examined. The alloys examined include Fe-54.9 at.-% Pd, Ni-45.4 at.-% Pd, and Co-45 at.-% Pd. The paper describes the growth of bulk single crystals of these alloys using Czochralski technique. X-ray diffractometer was used to obtain rocking curves that were used to determine the [001] crystal direction. Magnetostriction in [001] direction was measured using strain gages. Magnetic properties were measured using a vibrating sample magnetometer. Ni-Pd showed the highest magnetostriction values among the congruent melting compositions. Magnetic and magnetostrictive behaviors of these alloy single crystals are presented.

Jan 1, 2005

By Pengfu Tan

Converter slag chemistry control has played an important role in optimizing converter operations. A thermodynamic model of copper P-S converter has been developed to predict the behavior of magnetite in the converter slag. Predictions of bath temperature, slag and matte compositions, and magnetite content in the slag have been validated by industrial data. The effects of fluxing strategy, returns and skim charges, oxygen enrichment, and temperature on the magnetite formation in the slag have been predicted and discussed. Some improvements of the industrial operations have been presented.

Jan 1, 2005

By Chang Chia -Fu

The generic structure of our bimesogens is shown in and for a typical blue-phase mixture of the type we describe here. We use mixtures of the ratio 33.4% (n =2.6), 34.1% (n =6.57), 36.6% (n= 11.15) with of the high twisted power (HTP) agent BD H1381(available from Merck Chemicals and described in ref. We then studied the electric-field dependency of the selective reflection in BP I* at 20.7 °C by applying increasing and the decreasing pulsed alternating current (a.c.) electric fields (100 Hz).

Jan 1, 2006

By Chen Song

Keywords: Mixed extractant, Copper, Cobalt, Nickel, Synergistic effect During separation process of copper and cobalt from nickel sulphate solution, the effects of constitutions and compositions of mixed extractant D2EHPA and PC88-A or Cyanex 272, has been studied. In one step extraction cycle, the following results are obtained:[Ni]/[Co]>4000 and [Ni]/[Cu]>40000 in nickel sulphate solution, [Co]/[Ni]>1000 and [Co]/[Cu]>30000 in cobalt chlorinate solution, [Cu]/[Ni]>10000 and [Cu]/[Co]>200 in copper sulphate solution. It was elucidated that the above-mentioned synergistic mixtures can effectively separate cobalt and copper from nickel sulphate acid solution and achieve a greater synergistic effect.

Jan 1, 2005

By Daniel Bennett

There are few methods currently applied towards on-line bulk mineralogical analysis. Yet on-line knowledge of process mineralogy could potentially provide large benefits, such as increased extraction efficiency or resource optimization. The work described in this paper involves the development of radio frequency methods for bulk mineralogical analysis. Some resonances that occur in the radio frequency spectrum are mineral specific, and potentially allow quantitative estimation of mineralogy in an ore stream. Results will be presented on the specific detection of chalcopyrite. Initial quantitative measurements investigating matrix effects have indicated the feasibility of on-line mineralogical estimation using radio frequency techniques.

Jan 1, 2006

By D. C. Lynch

While a sizable amount of data exist as to the activity and distribution of minor elements between matte and metal, there has been no unifying theory presented delineating the form of dissolution of these elements in molten sulfides. In order to alleviate that deficiency the literature concerning the behavior of As, Sb, Bi and Pb in mattes is reviewed. Models present in the literature, regarding the thermochemical behavior of minor elements, are tested, and new models are presented and evaluated using thermodynamic theory. The results of those analyses are used to predict optimum conditions for the volatilization of minor elements. The dearth of data on the behavior of minor elements in nickel mattes requires that this review focus on copper- iron mattes. An effort is made, however, to utilize basic knowledge regarding nickel sulfides and the interaction of nickel with the minor elements to predict the behavior of those elements in nickel-copper and nickel-iron mattes.

Jan 1, 1993

By Hirokazu Narita

Keywords: solvent extraction, precious metals, thiodiglycolamide, rapid separation, hydrochloric acid The solvent extraction of some precious metals (Pd(II), Pt(IV), Rh(III) and Au(III)) and base metals (Fe(III), Cu(II) and Zn(II)) in a hydrochloric acid solution was carried out using N,N'-dimethyl-N,N'-dioctyl-thiodiglycolamide (MOTDA) dissolved in the mixed solution of 80 vol-% dodecane and 20 vol-% 2-ethylhexanol. The extraction percentages of Pd(II) and Au(III) in the 0.01 M MOTDA-1.0 M HCl solution system are 99.6% and 71.8%, respectively. In contrast, the other metal ions are hardly extracted under the studied conditions. The Au(III) and Pd(II) extracted in the organic phase are easily back-extracted with a 1.0 M thiourea/1.0 M HCl solution. A comparison with the conventional extractant for the Pd(II) separation, di-n-hexyl sulfide (DHS), revealed that the extraction rate of Pd(II) with MOTDA is much greater than that with DHS. The extraction percentage reached over 99% in less than a 2 min contact time. However, in the DHS-Pd(II) system, it takes about 240 min to achieve the extraction equilibrium. Furthermore, MOTDA can quantitatively extract Pd(II) up to half the molar amount of MOTDA. Therefore, MOTDA is a promising extractant for Pd(II) from the HCl solution after the removal of Au(III).

Jan 1, 2005

By Vijaya Thangavelu

Biological leaching of low-grade nickel laterite is based on a non-traditional leaching of oxide minerals using heterotrophic micro-organisms. The organisms solubilise metals by excreting organic acids; these acids then form complexes with heavy metals. High salinity of water supplies and soils in the vicinity of nickel laterite ore bodies is a major abiotic stress to fungi and represents a major challenge in the application of bioleaching process in-situ. Salinity exposes fungi cells to Na+ toxicity and osmotic stress. This study examined the salt tolerance development of Aspergillus foetidus based on gradual acclimatization of organism, its salt threshold and the salinity effect on its metabolism. The biological leaching of weathered saprolite ore with the resulting halotolerant organism under saline conditions was assessed. It was observed that salinity stress affected the organism?s growth and energy utilization

Jan 1, 2006

By Ryan Walton

The Flash Converting Furnace at Kennecott Utah Copper converted over 465kmt of high-grade matte in 2002 but was restricted due to low matte production to 395kmt in 2003. This paper presents updated operational performance data and describes improvements implemented since the mid 2001 rebuild. Matte burner feed distribution, silica and arsenic impacts on settler lime-based slag operability, blister laundering, uptake/boiler accretion control, and dust sulfation will be discussed, as well as current development requirements dictated by operational imperatives and furnace modification plans.

Jan 1, 2005

By D. Gu, R. G. Anthony, C. V. Philip, M. E. Huckman

"In this paper, we review the equations needed to construct an ion exchange column model. These models contain three major components: 1) a differential material balance around the column, 2) a differential material balance around an ion exchange particle, and 3) a constitutive equation for diffusive flux. We then examine the ability of a fairly simple mathematical model to predict ion exchange column experimental data. This model contains the traditional absorption theory equations and is used to predict the behavior of a column filled with a hydrous crystalline silico-titanate and which is removing trace amounts of Cs+ from a high pH, complex electrolyte solution. Finally, we propose replacing Fick's law with the Nemst-Planck equation as the constitutive equation for diffusive flux. We use a NemstPlanck type model to predict batch experimental data, then evaluate it by comparing it's ability to predict experimental data to that of a more traditional Fick's law type model. The data from this comparison suggests that the Nemst-Planck type model yields better results.IntroductionMillions of gallons of strongly basic, radioactive waste are currently stored in underground storage tanks at Hanford and Savannah River and several locations within the United States. Due to the limited life expectancy of the tanks, there is a pressing need to remediate these wastes. This need has prompted the recent development of new ion-exchange materials for removing radioactive elements from aqueous solutions. A novel material called TAM-5 has been developed jointly by Texas A&M University and Sandia National Laboratories. TAM- 5, a crystalline silico-titanate, is highly selective for Cs + in the complex electrolytic solutions typical of these wastes. It is stable in very basic solutions and in radioactive environments [1, 2 ,3]. In laboratory testing to determine the selectivity of various materials, TAM-5 was superior to other candidate ion exchangers [4, 5]. The selectivities were determined by measuring a distribution coefficient, Kd, which is defined as the concentration, gig or mmols/g of Cs in the solid phase divided by the concentration, mg/L or mmols/mL, of Cs in the liquid phase. The units of Kd are ml/g or L/kg. Table 1 shows Kd values for TAM-5 compared to 9 other candidate materials in a typical waste solution [6]."

Jan 1, 1996

By Pengfu Tan

The control of converter slag chemistry and slag viscosity has played an important role in optimizing converter operations. A thermodynamic model of copper P-S converter and a viscosity model of converter slag have been used to predict the chemistry and viscosity of converter slag. The effect of oxygen potential, SiO2/Fe in slag, detection of slag blow endpoint, and temperature on slag viscosity, liquidus temperature of converter slag and skimming operation has been discussed. Some applications of the industrial operations have been presented.

Jan 1, 2006

By Kim Fagerlund

Boliden Harjavalta Oy operates a copper smelter in Finland, which is based on flash smelting together with Peirce-Smith converting of copper matte. This paper reviews a case study when a high arsenic feed mixture was successfully eliminated in order to guarantee the anode quality. Based on theoretical and practical knowledge in slag chemistry at Outokumpu Research, the CaO-fluxing practice was introduced. Description of a thermodynamic simulation using MTDATA and implementation of the results into converting practice is given. Results showed that the impurity fluctuations in raw materials could be effectively controlled by efficient utilization of different slag chemistry.

Jan 1, 2005