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By M. Tomita

One of the most essential factors for a custom smelter to strengthen its competitive power is to Improve its comparative standing in purchase of concentrates from the world market. It is especially critical for Japanese smelters who depend almost 90% of their raw materials on import. In order to accomplish this breakthrough, the development of the new technology which enables us to treat concentrates containing higher Impurities is inevitable. Nippon Mining Company Ltd. made an intensive research on processing complex ore for three years from 1979, and successfully developed an original hydrometallurgical process to treat converter dust for eliminating impurities from the copper smelting circuit. The commercial plant was constructed at the Saganoseki Smelter & Refinery in 1982, and its nine years operation has been satisfactorily proven the advantages of the technology. The concept of this process and its operational performance are discussed.

Jan 1, 1992

By Eiji Iwamura

"Two types of diamond-like carbon (DLC) films with different microstructures were prepared by unbalanced magnetron sputtering, and the tribological properties of the nanoscaled DLC multilayer coatings consisting of alternating layers of graphitelike and amorphous-like microstructures were examined. The DLC microstructure was characterized by certain features of graphite-like clusters, in that some of them had onion-like structures. The films filled with the clusters were obtained in a condition with an incidence of high influx of energetic electrons, and the other films without apparent cluster structures were formed in a condition with ion bombardment controlled by negative bias voltage applied to substrates. Stacking each film layer-by-layer, the nanoscaled multilayered coatings showed superior tribological properties to individual single-layered films due to the combination of properties induced by the difference of microstructures.IntroductionIn various tribologiql applications, it is necessary for diamond like carbon (DLC) coatings to have adequate adhesion, significant hardness and a concomitant low friction coefficient. A number of deposition techniques and coating structures have been proposed to achieve suitable DLC properties [1-3]. However it is still difficult to obtain a satisfactory level of combination of the properties particularly desirable for engineering applications.In this study, the features of unbalanced magnetron sputtering were demonstrated with the effect of ion and electron bombardment. Two types of microstructures , namely amorphous-like and graphite-like, were prepared by changing the condition of the charged particles bombardment during deposition. Using the difference of properties induced by the microstructures, nanoscaled DLC multilayered structures were examined in an attempt to improve tribological properties."

Jan 1, 2000

By Sang Han Son

The vapor pressures of FeCI2 and ZnC12 in the FeCl2-ZnCl2 system were measured by the transpiration method at 873K and 917K. The vapor pressure data were interpreted to indicate the formation of complex ions in the FeCl2-ZnCl2 melts. It is presumed that the complex molecule FeZnCl4 as well as FeCI2 and ZnCI2 exists in the vapors in equilibrium with molten FeCl2-ZnCl2 mixtures. The activities in the FeCl2-ZnCI2 system are shown a negative deviation from Raoult's law. These results suggest the formation of complex ions such as ZnCl42- in molten FeCI2-ZnCI2 mixtures.

Jan 1, 2003

By Florian Kongoli

The production of a homogeneous self-fluxing sinter is an important step in iron making processes. A good sinler should have good permeability and reducibility and has to keep those characteristics for a certain time. An early melt down of the sinter in the blast furnace, where its solid state reduction is essential, would cause many problems such as low permeability and reductibility. Nevertheless, the important factors that influence these characteristics, such as the chemistry of the sinter and the fluxing effect during sintering and sinter reduction conditions have not yet been clarified, In today's new reality where many new minor components such as Al2O3 and MgO enter to the sinter through raw materials, the quantification of the fluxing effects during sintering becomes even more important. In this work, the liquidus surface and phase relations of the sinter primary melts in the CaO-FeO-Fe203-Si02 system at sintering conditions have been quantified. The fluxing effect of oxygen potential, Al2O3 and MgO has also been quantified by the means of some practical diagrams that can directly help the optimization of the sintering processes.

Jan 1, 2003

By M. K. Yelloji Roa

Effect of conditioning with Thiobacillus ferrooxidans on the floatability of sphaierite and galena has been determined in this work. The flotation behavior of the conditioned minerals clearly shows that such bacterial conditioning does produce marked modification of their surfaces. The variables affecting the surface modification and thereby the flotation response of the minerals were found to be cell concentration used for bacterial conditioning, the period of biotreatment and the pulp density. Importantly, while the enhancement in flotation obtained due to sulphuric acid treatment was retarded by biotreatment in the case of galena at all cell concentrations due to electrochemical effects, such decrease occurred in the case of sphalerite only at cell concentration sufficiently high for their attachment to the mineral surface. The effect of bacterial conditioning has significant implications to the differential flotation of sphalerite and galena. Mechanisms responsible for the modification of the surface properties of these sulphides due, to bacterial conditioning are discussed.

Jan 1, 1991

By Jim Sundal

Primary steel manufacturers using electric arc furnaces generate one of the largest hazardous waste streams nationwide. The waste stream, known as electric arc furnace dust, is a listed hazardous waste with the designation K061. Oregon Steel Mills, Inc., (OSM) of Portland, Oregon, has implemented a process known as Glassificationn, which uses KO61 as an ingredient in an onsite recycling process. Because OSM was able to demonstrate that the Glassificationm recycling process beneficially uses all toxic constituents in the electric arc furnace dust and that the recycling process produces marketable products, the process is not subject to Resource Conservation and Recovery Act (RCRA) permit requirements. The marketable products manufactured using Glassificationn include roofing granules, ceramic glazes and colorants, abrasive blasting media and, more recently, synthetic slag fluidizers. The purpose of this paper is to identify the regulatory issues for recycling hazardous waste and demonstrate that OSM glass frit is effective as a slag fluidizer in primary steel manufacturing.

Jan 1, 1994

By R. W. McCallum, B. Jensen, K. W. Dennis

"There are substantial challenges in the exploration of magnetic materials in the R-TM-X system (R =rare earth, TM= transition metal, X =stabilizing element) where Xis an element which has high vapor pressure, high reactivity, toxicity, or a refractory nature. This research focuses on discovering new phases with high anisotropy and high magnetization through closed diffusion couples inside high purity Fe crucibles. Either vapor-solid reactions or powder metallurgy techniques are then employed to isolate a stoichiometric sample based on a potentially magnetic phase found in the diffusion couple. For this research, X = F, Ca, Sr, Se, Zn, Bi or Cd, TM= Fe, and R = Nd. New ternary phases have been discovered with WDS and EDS, and magnetic transition temperatures have been measured with a SQUID magnetometer and VSM.IntroductionSince the discovery of the RCo5 compounds in the 1960s, rare earth- transition metal (R-TM) magnets have been the main focus of permanent magnetic research over the last five decades. Iron-based magnetic materials were studied next in attempts to avoid the unstable price of cobalt as well as the high price of Sm, the top performer in the RCos and RzC011 series. This hunt eventually led to the discovery of Nd2Fe14B with a theoretical BHmax of 64 MGOe, nearly double that of the previous samarium based magnets. The next few decades were devoted to enhancing the magnetic properties ofNd2Fe14B by the improvement of processing techniques and the additions of alloying elements. The only complete elemental substitution discovered in this system was R1Fe14C, which did not improve magnetic properties. It is probably safe to say that most ternary R-TM-X systems, where Xis any element that may stabilize a ternary phase, have been investigated if they may be prepared by conventional processes such as arc or induction melting. The present study offers a systematic approach to developing a novel diffusion couple technique in which the volatile, reactive or toxic alloying elements are laser welded inside a high purity Fe crucible. This experimental setup will prevent the oxidation of the rare earth element, as well as contain the volatile X element. As the goal of the research was to find new rare earth permanent magnets, only phases which contained greater than 60 wt% Fe were investigated. 247"

Jan 1, 2012

By L. I. Rosato

A novel hydrometallurgical process for the recovery of silver and gold from neutral leach residue that is based upon leaching with thiourea, is described. Laboratory and pilot plant studies have shown that 80-90% of the silver and 60-70% of the gold can be recovered by:? ( i) leaching zinc calcine with 'Spent electrolyte at pH 2.0-3.0 to generate a precious metal-bearing zinc ferrite residue, (ii) leaching of the thickened zinc ferrite with 3-5 g/L thiourea in a six stage carbon-in-pulp circuit, (iii) elution of silver and gold from the loaded carbon with a thiourea- butanol solution, (iv) thermal regeneration of the stripped carbon and (v) recovery of the precious metals from the pregnant eluate by cementation with zinc dust. The reasons for adopting the thiourea CIP leach and the preferred operating parameters for each process step are presented. The requirements for the destruction of any thiourea transferred to the zinc circuit are outlined, and the results of an integrated one tonne/day pilot plant operation at Canadian Electrolytic Zinc are given.

Jan 1, 1990

By N. Y. Ma

Solid wastes produced in ironmaking and steelmaking off-gas cleaning systems often contain zinc. The zinc level in these solid wastes is generally too high to recycle the wastes for iron through blast furnaces, but too low to economically treat the wastes for zinc through zincrecovery facilities. The behavior, status, and distribution of zinc in the ironmaking and steelmaking off-gas cleaning systems have been analyzed from three aspects: thermodynamics of zinc condensation, oxidation and deposition, correlation of zinc concentration with particle size and density, and aerodynamics of dust particles in the off-gas cleaning systems. Theory and supporting data show that spontaneous separation of zinc from iron-bearing dust occurs in the ironmaking and steelmaking off-gas cleaning systems. Dry off-gas cleaning systems provide the most favorable conditions and environments for zinc to separate from the dust. If highefficiency dry separators were applied and appropriately arranged in the off-gas cleaning systems, zinc would be concentrated, and the majority of the solid wastes could be recycled for iron recovery through blast furnaces.

Jan 1, 2008

By T. T. Chen

The manganese oxide scales, consisting mainly of MnO2, characteristically occur in banded colloform structures which adhere to porous layers of PbSO4 and PbO2 that oxidized from the rolled Pb-0.7% Ag anodes. Hydrous Mn oxides, Mn3O4 and amorphous Mn oxides are believed to be also present. Tiny particles of gypsum, PbSO4, SrSO4 and AgCl are entrapped in the colloform masses. The gypsum originated from the Zn electrolyte; strontium carbonate was added to the ZnSO4 solution to control Pb, and silver originated from the anodes. Some of the colloform bands contain minor amounts of Pb, implying a limited degree of dissolution of the Pb during electrolysis. Other colloform bands incorporate trace amounts of Zn. Colloform structures permeated with silica gel are presumably caused by the high silica content of the electrolyte.

Jan 1, 2009

By M. Misra

The removal of lead and other heavy metals present in an active US Army small arms firing range soil was evaluated in a pilot scale test program at Ft. Polk, Louisiana. Two different acid based extraction processes in conjunction with conventional physical separation methods were used. Physical separation processes consisting of screening and gravity operations removed most of the coarse lead particulates and slugs. Hydrochloric acid leaching followed by precipitation of lead as hydroxide recycled clean soil containing less than 500 mg/L. total lead and less than 5 mg/L TCLP lead. Lead extraction efficiency with hydrochloric acid was 96 percent. The results of lead removal by physical separation in conjunction with acetic acid leaching were not consistent over the whole test period and the total soil processed.

Jan 1, 1998

By Xue Ping

Sm2Fe17 alloy is an important precursor for the preparation of Sm2Fe17Nx magnet, which possesses a higher Curie temperature, larger anisotropy field, better resistance to oxidation and thermal stability. In this paper, the wet chemical co-precipitation was developed for synthesis of the Sm-Fe alloy oxide precursor. Based on the principles of simultaneous equilibrium and mass balance, a series of thermodynamic equilibrium equations of Sm(III)-Fe(II)-NH3-C2O4 2--H2O system at ambient temperature were deduced theoretically and the thermodynamic diagrams of lg[M2+]T (M=Sm, Fe) versus pH at different solution compositions were drawn. Then, the experiments were done to address the various effects on the wet chemical process, including solution pH value, reactant concentration, reaction temperature and aging time, etc. It is found that by precise control of the process, the Sm-Fe alloy oxide precursor was synthesized with fine crystallization and special size &size distribution.

Jan 1, 2008

By Minji Jun

Leaching of the surface-coated metals from waste acrylonitrile butadiene styrene plastics (WABSP) has been investigated in the ammoniacal solution. The ammoniacal leaching of WABSP (typically containing 4.1 wt% Cu, 1.3 wt% Ni, 0.03 wt% Cr) efficiently dissolved copper and nickel, leaving unleached chromium as fine particles. The results indicate that the anions of different buffer media for metals leaching follow the order: CO3 2− > Cl− > SO4 2−. A declined leaching with high NH4OH–(NH4)2CO3 ratio (8:1) and a steep rise in extraction with high pulp in solution revealed the influence of anion (CO3 2−) and cation (Cu2+) present in the system. The leaching performed in carbonate solution by maintaining 5.0 M total NH3 concentration as NH4OH–(NH4)2CO3 ratio, 4:1; pulp density, 200 g/L; agitation speed, 400 rpm; temperature, 20 °C and time, 120 min yielded the maximum extraction (>99%) of copper and nickel. The study reveals a plausible recovery of the surface-coated metals from the WABSP without altering the properties of polymer material that can be recycled separatel

By Kimio Itagaki, Torn Matsumoto, Makoto Ohtsuka, Kentarou Harada

"The structure and hydrogen-absorption properties of LaNis thin films were investigated in the present study. LaNis thin films were prepared by a sputtering method with a radio-frequency power, Ws, of 50 -400 Wat substrate temperature, Ts, of323 -573 K. Nickel content of the films decreased with increasing Ws, however, there was no dependence on Ts. At low Ws and low Ts, amorphous films were deposited. In other conditions, the films were polycrystalline. The films prepared at high Ws and low Ts, or at low Ws and high Ts, exhibited only a (h k · 0) peak in the X-ray diffraction profiles. This indicates that the c-axis of crystalline films was oriented parallel to the substrate plane. At high Ws and high Ts, the films with columnar structure were obtained. Hydrogen-absorption capacity of the thin films increased with increasing Ws. The pressure plateau did not appear on the pressure-composition isotherms. The films deposited at high Ts represented a higher equilibrium pressure.IntroductionThin films of hydrogen storage alloys can be applied for an electrode of rechargeable battery or fuel cell, a filter for H1 purification and various kind of sensor. Some studies on the preparation of the thin films of LaNi5 intermetallic compound, which is a typical hydrogen storage material, have been done hitherto. Adachi et al. , 2) and Sakaguchi et al. 3) prepared amorphous and crystalline LaNi5 thin films using flash evaporation of alloy powders and measured the pressure-composition isotherm for the prepared film utilizing a quartz crystal mass monitoring (QC:MM) method. It was found that the prepared amorphous film absorbed hydrogen without disintegrating into the powders and the hydrogen-absorption capacity of the films increased with the degree of crystallinity. Sakai et al. 4) reported that the maximum hydrogen storage capacities of amorphous and crystalline LaNi5 thin films, fabricated by a RF sputtering method using combination targets, were about 40 mA h g-1 (LaNisHo.7) and 160 mA h g-1 (LaNi5H2.6), respectively. Uchida et al. 5, 6) prepared LaNi5 thin films using flash evaporation of alloy powders and measured volumetrically the pressure-composition isotherm for the prepared film. It was reported that the hydrogen-absorption capacity of the films changed by the annealing treatment."

Jan 1, 1998

By Zongshu Zou, Qiang Li, Mingming Li, Mingxia Feng

The impingement onto the surface of bath by top-blown jets is a significant process characteristic in BOF and EAF steelmaking process. The cavity is one of the most important outcomes of the interaction and plays an important role on reaction kinetics and reactors performance. But to date, the understanding to cavity is still so limited. In present study, a water model for a BOF converter is established and the dimension of cavity profile is investigated. The effects of lance height, gas flow rate, nozzle inclination angle and the amounts of slag are discussed. The results show that penetration depth increases with the increase of gas flow rate and the amount of slag, and the decrease of lance height and nozzle inclination angle. Furthermore, a theoretical model of cavity dimension is proposed for multiply jets impinging liquid bath on the basis of energy balance at the stagnation point of cavity.

Jan 1, 2015

By Chang Wei, Zhigan Deng, Minting Li, Cunxiong Li, Xingbin Li

A direct hydrometallurgical process of extraction molybdenum and nickel from molybdenum-nickel ore by pressure water leaching without reagent was studied. The extraction of Mo and Ni from molybdenum-nickel ore by oxygen pressure leaching, which exploit the characteristic of molybdenum-nickel minerals contain high concentration amorphous sulfide which has highly active, and make the most of easily oxide to sulfuric acid and sulfate at low temperature and excess oxygen presence of the amorphous sulfide. Under oxygen pressure conditions, considerable molybdenum and almost all the nickel were extracted into solution in the leaching process. The results show that with the leaching time for 3~4h, temperature at 150o C, liquid-to-solid ratio of 2mL/g, mineral granularity of 0.074mm, oxygen partial pressure of 0.4~0.5MPa without other reagent, molybdenum leaching percentage can be over 80% and nickel leaching percentage can be more than 97%. Furthermore, about 80% sulfur in the Mo-Ni ore has been transformed into sulfuric acid.

Jan 1, 2014

By R. Cameron

The growing use and acceptance of electric vehicles (EV), as evidenced by the record sales of over 750 thousand vehicles in 2016 and a current global EV stock of 2 million vehicles, is putting pressure on sourcing raw materials such as cobalt, and to a lesser extent, nickel. Global supply is poorly diversified, with 50– 60% of global cobalt production sourced solely from the Democratic Republic of Congo (DRC). One potential source for cobalt and nickel are low-grade nickeliferous pyrrhotite tailings, of which 50–100 million tonnes are present in the Sudbury area alone. This paper presents the extraction of cobalt and nickel from this material using a combination of flotation and bioleaching technologies. The findings of a high-level techno-economic analysis of the proposed processing flowsheet are presented.

By G. C. Amstutz

The topic of the industrial applications of mineralogy is a vast field which can be adequately covered only in a large book or by a two or three semester course. This paper recalls experiences of the writer in this field, a task requested by the Process Mineralogy Committee. Therefore, this paper is largely an account of the industrial mineralogy problems I was involved with, since my student years, Although I will treat each application only briefly, it is hoped that they will illustrate to the students in the field how varied are the applications of mineralogical methods. In this respect, I want to emphasize that it is important for mineralogy teachers to point out the usefulness of mineralogical methods much more often in their courses. Not only does that help prepare young individuals for industrial careers, but also it arouses their feeling of consciousness of public responsibility which is an important attribute for the world's scientists. When professors utilize the varied applications in their teaching of mineralogical methods students then understand better the significance of learning those methods and appreciate the many years of necessary university preparation. The first time I was involved in an application of mineralogical methods was about 1944 as a student of Professor Paul Niggli. He was asked to study the problems of ice crystallization on wings of airplanes. The ice formed at high altitudes and during the winter. This was not outside his realm of expertise because he was the main initiator of the Snow Research Institute on the Weissfluhjoch in Switzerland. I believe that the work of this Institute was an important factor in stimulating much of the snow research subsequently carried out at the United States Army Snow Research Center, which was located at that time in Willmette near Chicago. Dr. Bader, one of Paul Niggli's former students, was the Director of Research at Wilmette at that time and for quite a number of years thereafter. A mineralogist-crystallographer can make important contributions to a better understanding of the problems of snow and ice formation, avalanche hazards, and the prevention of hail. The habits of snow crystals are essentially a function of the temperature and the humidity,

Jan 1, 1982

By Ray Y. Lin

Chemical vapor deposition of tungsten carbide on the surface of steel has been investigated at temperatures between 400 and 550C in an atmosphere containing tungsten hexafluoride, hydrogen and benzene. The tungsten fluoride flow rate was maintained at 20 ml/min. The hydrogen flow rate was at 100 ml/min. The benzene concentration varied from 1.15 to 5.56% in the reaction gas. It was observed that the higher the temperature, the faster the deposition rate for tungsten carbide. But the dependence of the deposition rate on the benzene concentration was not systematic. From the x-ray diffraction analysis, it was observed that W, W2C and WC are all presented in the coating. The amount of each phase presented in the coating depends on the temperature and, to a less extent, on the benzene concentration. The microhardness measurement has also been done for all CVD carbide coatings obtained in this study.

Jan 1, 1992

By Manju Gurung, Birendra Babu Adhikari, Keisuke Ohto, Hidetaka Kawakita, Katsutoshi Inoue, Shafiq Alam

Novel bio-adsorbent gel was prepared by immobilizing functional groups of glycidyltrimethyl ammonium chloride, a kind of quaternary ammonium chloride, onto polymer matrices of persimmon extract for the recovery of precious metals such as palladium(II) and platinum(IV) from chloride media. It was found that this adsorption gel exhibits high selectivity to gold(III), palladium(II) and platinum(IV) over base metals such as copper(II) and iron(III) while crude persimmon extract, the feed material, exhibits high selectivity only for gold(III). From the adsorption isotherms study, the maximum adsorption capacities for gold(III), palladium(II) and platinum(IV) were evaluated as 3.30, 1.67 and 1.00 mol/kg, respectively. Those for palladium(II) and platinum(IV) are higher than those of simple quaternary ammonium chloride type of chemically modified persimmon tannin gel and commercially available anion exchange resin.

Jan 1, 2016