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By M. Kawakami

In the blast furnace, the reduction of iron oxide and gasification of coke occur simultaneously. It is well accepted that the gasification reaction controls the simultaneous reaction. Therefore, it is important to develop highly reactive carbonaceous materials. It is also known that the reaction is accelerated catalytically with the addition of some materials. In the present work, the catalytic effect of iron, nickel and CaO on the gasification of graphite and coke was examined. The catalytic effect of iron, nickel and CaO on the reaction rate of graphite was noticed The effect was larger at lower temperature. At 1373 K, the effect almost vanished. The effect was larger in the order of CaO, iron and nickel. The reaction rate of de-ashed coke increased by the addition of iron and nickel. The effect of iron was larger than that of nickel. The effect was larger at higher temperature, which was contrary to the case of graphite. The reactive surface area increased also by the addition. Therefore, the catalytic effect on reaction rate might be attributable to the increase in the reactive surface area.

Jan 1, 2006

By K. Takahashi, G. Dodbiba, T. Fujita, N. Sato, S. Matsuo, K. Okaya

Different materials are used for manufacturing various parts of a cellular phone. Considering that a great number of mobile phones are being discarded every year, it is important to recover these materials and then recycle them in order to save resources. The primary objective of this work is therefore to find and suggest ways on how to recover various materials from discarded cellular phones for recycling. Much effort, for example, has been put in recovering and recycling tin oxide (ITO), a mixture of indium (III) oxide, (UI2O3) and tin(IV) oxide from the discarded liquid crystal displays (LCDs). Here we report a simple and cost-effective process, which includes a HC1 treatment process for altering the structure of the indium (III) compound into a chlorideinduced indium compound, in order to facilitate the vaporization of indium at a relatively low temperature. The experimental results indicated that 96.2 % of indium can be recovered from ITO, when the sample was heated at 973 K for 90 minutes. In addition, some thermodynamic calculations were also carried out in order to better understand the mechanism for chlorideinduced vaporization of indium.

Jan 1, 2011

By P. Louis

Although cobalt is known and used for its hardness and wear resistance, ductile cobalt can be obtained by electrolysis in chloride solutions, under the following conditions : pH : 1.5 - 2, Co++ : 30 - 60 g/l, current density : 100 - 500 A/m2, temperature 40 - 70°C. No explanation was found for the ductility of the deposit under these conditions. Indeed the ductile P (FCC) cobalt and the hydrogen contents in the cobalt deposits are nearly the same as those obtained in a sulfate media, which gives brittle depo¬sits under equivalent electrolysis conditions. Malleable cobalt sheets can be easily obtained under the proposed conditions which could lead to new applications for cobalt.

Jan 1, 1988

By Jr. Foot

The Bureau of Mines, U.S. Department of the Interior, investigated flotation methods for recovering fluorite and byproduct beryllium from the Fish Creek deposit of Nevada. The preferred method includes (l) fluorite rougher and cleaner flotation, (2) de sliming at 20 micrometers, (3) muscovite flotation, (4) silicate flotation, (5) hypochlorite wash of silicate concentrate, and (6) beryllium rougher and cleaner flotation from the silicate concentrate, Laboratory results showed that over 94 pct of. the fluorite was recovered in a concentrate containing 96 pct CaFz. Beryllium flotation produced .concentrates .containing in excess of 5 pct BeO with recoveries over 70 pct. A 1.00-lb/h continuous flotation unit was constructed to demonstrate this procedure,

Jan 1, 1985

By S. S. Ibrahim

The left behind material after the combusion of fossel fuel in some power stations in Cairo; weighing tens of tons every years, was investigated. The material called "Fly Ashes" containing 7.5% Ni, 10.0% V and 9.50% Cr; could be considered as a promising source of such valiable elements. As well as the small grain size (050 70 "m) of the material, and besides the complexity of their formation history, hydrometallurgical methods appeared to be the effective technique to deal with. Yet, preconcentration is possible by means of magnetic and gravity separation methods. The end product is assaying 16.60% Ni and 20.2S!; V with weight recovery of about 60.15%.

Jan 1, 1995

By K. E. Gonsalves, G. M. Chow

"Nanostructured powders (particle diameter of 1 - 100 nm) have uses in electronic, magnetic, structural, thermal applications as well as advanced processing of materials. Among many methods of making nanostructured powders, chemical routes offer many attractive features such as feasibility of cost-effective bulk quantity production, design of chemistry at the molecular scale, and chemical homogeneity of the powders. In this talk, two systems of chemically synthesized nanocomposite powders are presented, namely, granular magnetic materials of Fe-Cu and Co-Cu, and thermal-structural materials of AIN-BN. Synthesis and processing, characterization and properties of these materials are discussed.IntroductionNanostructured powders (particle diameter of 1 - 100 nm) are attractive materials because of many useful properties (e.g. catalytic, optical, magnetic etc.) and processing advantages (e.g. lower sintering temperature) [1]. There are many methods of making nanostructured powders, for example, physical and chemical vapor deposition, mechanical attrition, and solution chemistry [1, 2]. A common method of making composite powders involves the grinding, mixing and blending of constituents powders, but it has the limitation of inhomogeneous mixing. Chemical routes have many useful features. Using solution chemistry, precursors can be molecularly tailored and homogeneously mixed at the molecular level. The chemical approach may result in better properties of the final product. Compared to vapor-phase fabrication techniques, chemical routes are more cost-effective in producing large quantity of material. In addition, control of particle size, size distribution and stabilization of the nanoscale particles against agglomeration can be more effectively manipulated via solution chemistry.In this paper, we present an overview of some of our work in nanocomposite powders prepared by solution chemistry. Metallic systems of FeCu and Co-Cu, and ceramic system of AIN-BN are discussed. The powders were characterized using x-ray diffraction (XRD) , scanning electron microscopy (SEM), conventional and high resolution transmission electron microscopy (TEM, HRTEM), vibrating sample magnetometry (VSM), inductively coupled plasmaatomic emission spectroscopy (ICP-AES)."

Jan 1, 1994

By M. Pakala, Z. Fan, Ray Y. Lin

Deposition of hard chromium coatings using electrodeposition is accompanied by emission of hexavalent chromium mists which is a carcinogenic. Hence alternative chromium deposition technologies are being investigated. Sputter deposition is a strong candidate to economically deposit hard chromium coatings in an environmentally friendly way. Chromium coatings of 2-3 µ m thickness were deposited on plain carbon steel coupons using RF magnetron sputter deposition. Depositions were carried out with 0 to 22 vol% nitrogen in the plasma. Structure of the coatings was studied using x-ray diffraction analysis With increasing nitrogen contents, formation of the two nitride phases was observed. The pure chromium phase was detected in coatings with up to 7% nitrogen in the sputtering gas. The solid solution of nitrogen in the pure Cr phase coating was identified by shifts of Cr x-ray diffraction peaks to higher d-spacing. The microhardness of the coatings deposited at a substrate temperature of 200°C showed an increase in hardness with increasing nitrogen content from 600 kgf/mm2 (5.9 GPa) at 0% nitrogen to I250 kgf/mm2 (I2.25 GPa) at 9.5 % nitrogen and a subsequent decrease in hardness to I 100 kgf/mm2 (11 GPa) beyond 9.5 % nitrogen in the sputtering gas. This corresponds to the formation of the hard Cr2N phase, at 9.5 % nitrogen, and CrN phase, at I5.7 % nitrogen. The reported bulk hardness values of Cr2N and CrN are I600 kgf/mm2 (I5.7 GPa) and I 100 kgf/mm2 (11 GPa) respectively. For pure Cr phase coatings, there is a slight increase in hardness for coatings deposited at 7. I % nitrogen from that without nitrogen in the sputtering gas. This could possibly result from the solid solution strengthening of the Cr lattice by nitrogen. For films deposited at 200°C, phases of the deposited films seem to be the overwhelming factor in controlling the microhardness.

Jan 1, 1998

A study was undertaken to remove the Se from waste solutions using a raw form of the biomass called Iota Chips derived from the seaweed, Eucheuma spinosum. Removal of Se from solutions was investigated as a function of time, pH, conc. of Se in solution (0.1 to 100 ppm) and lota Chips to liquid ratios of 10-2 to 10-5. For solutions containing initial conc. of 0.1 ppm Se, with the addition of Iota Chips at a solid to liquid ratio of 10-3, the Se conc. decreased to 0.03 ppm in about 3 hours. Iota Chips absorption capacity to the Se and its application to the treatment of the metallurgical processing effluents are discussed.

Jan 1, 1992

By J. E. Wey

Extraction of cobalt from cobalt sulfide and cobaltite flotation concentrate from the Blackbird Mine, Idaho, was investigated using an adapted strain of Thiobacillus ferrooxidans. Cobalt extractions as high as 100% were realized in the inoculated experiments, whereas only 4% extraction was obtained in the sterile run. The influence of pulp density on the rate and extent of cobalt extraction was also determined. It was found that the extraction of cobalt followed predominantly the indirect mode of bacterial activity. In this process, ferric iron oxidizes cobaltite to cobalt sulfate and ferric arsenate while being reduced to its ferrous state; the bacteria continuously re-oxidize ferrous to ferric iron. Electrochemical measurements using cyclic voltammetry suggested that cobaltite oxidation involved a number of intermediate reactions.

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 Moelans. N.

A method using an ex-situ electrochemical measurement device was developed to determine the oxygen potential of non-ferrous metallurgical slags. The electrochemical cell consists of the molten slag sample, an inert Ir electrode, a stabilized Zr02 solid electrolyte and a NilNiO reference electrode. Different slags from non-ferrous pyrometallurgical processes were analysed at I 100 and 1200 °C and pO2values between 10-3 and 10-12 bar were obtained. The measurements were evaluated with thermodynamic calculations and using processing considerations. It was found that the reproducibility and stability of the measurement was significantly improved by shielding the molten slag from the atmosphere by a thin layer of carbon, especially for slags with a low oxygen potential.

Jan 1, 2003

By Norbert Steiner

For the desulfurization of weak SO2 gas streams, Degussa developed a process using dilute H2SO4 solution containing H2O, instead of conventional gas scrubbing with all solid absorbent medium (limestone, MgO). The process is based on fast reaction of H2O, with SO2 yielding H2SO4 up to 70% strength, depending on off-gas temperature. Compared to the conventional systems with typically < 95% efficiency, independent on the raw gas SO2 concentration, residual SO2 concentrations of less than 20 mg/Nm3 can be easily achieved, corresponding to nearly 100% removal. These features render the H2O, process a very attractive, low capital cost technology to retrofit existing conventional desulfurization plants.

Jan 1, 1996

By Qingsheng Liu

A new method of recycling aluminum dross for preparation Al-Si-Ti alloy was studied in this paper. This was carried out in two processes. first the aluminum doss was pretreated by leaching and calcining process, the fine purity and phase of the intermediate oxide powder up to electrolysis demands, then, could be obtained when aluminum dross after washing have been leached for 2h at 100? in 20% hydrochloric acid and calcined for 2h at 1200?, which was treated by cryoite-based molten salt electrolysis. Finally, the Al-Si-Ti alloy was successfully obtained through electrochemical co-deposition in the cathode shows a typical as-cast microstructure. This new recycling method can produce high quality alloy and may bring remarkable economic and social benefits.

Jan 1, 2010

By Paul-Dominique Oudenne

For many years, CMI NESA has gained considerable experience in the field of alternative thermal processing processes by which useful by products result in addition to the destruction of the raw wastes. The CMI NESA pyrolysis process has been extensively applied to a wide range of sewage, industrial sludge and residues. This paper describes in details the development works carried out at the pilot stage as well as the key parameters of the process. Some of the industrial realisations are briefly described, the most recent one being the erection of a sludge pyrolyser on predried sludge at 90% dryness of a capacity of 100 tons of dry matter per day for the Valenton plant of the SIAAP (city of Paris).

Jan 1, 2006

By Mingming Zhang, Ramana G. Reddy

"Carbon dioxide (CO2) is one of the most common by-products produced during light metals production. It is considered to be the cause of greenhouse effects. Efficient reduction of CO2 can help minimize the rate of global warming and improving energy sufficiency. In this paper, a novel light metal production process was developed using ionic liquid electrolytes. This process has significant advantages compared to the traditional high temperature processes such as zero CO2 and CF4 emission, low energy consumption due to the low temperature operation and nonconsumable electrodes. Two types of anode materials (graphite, extruded carbon) were tested in electrolysis experiment. The results showed that both anode materials were stable (negligible weight loss). However, the extruded carbon was found to be superior to graphite in terms of current density and current efficiency. The calculated energy consumption for aluminum production was less than 10 kWh/kg at current densities up to 300 A/m2.IntroductionGlobal demand for ultra-light, ultra-strong, recyclable metals is growing as the world switches to low-emission vehicles, energy-saving devices and sustainable products. Aluminum demand is forecast to climb by 30 percent; magnesium demand by 200 percent, while for the emerging industrial light metal, titanium, the demand is expected to be at least double in the next decade. However smelting of light metals is the most energy intensive among all the steps of light metals production. For example, on an average it takes about 15.7 kWh of electricity to produce one kilogram of aluminum from alumina [1, 2, 3]. Advancements in energy efficiency have been steady, but slow, and most U.S. aluminum smelting production operates at 95% current efficiency. Besides high energy consumption, another major concern of the light metals smelting process is the emissions of greenhouse gases (GHG). Electrolysis green house gas emissions in the Hall-Héroult process can be split into three groups: 1) reduction reaction emissions, carbon dioxide (CO2) and carbon monoxide (CO); 2) process upset perfluorocarbons emissions; and 3) hydrogen fluoride (HF) formed from the moisture (H2O) present in the raw materials [2, 3]. Hydrogen fluoride gas can be captured and returned to the cells by the alumina dry scrubbing system used in modern facilities. A total of 5.31 kilograms of CO2 is generated from the reduction process for each kilogram of aluminum produced in the average U.S. primary facility. The perfluorocarbon emissions are related to the “anode effect.” If the concentration of alumina in the bath becomes too low, other reactions between the carbon anode and the bath occur and tetrafluoromethane (CF4) and hexafluoroethane (C2F6) are generated. These gases have high global warming potentials (GWP), which is a ratio developed to compare the ability of each greenhouse gas to trap heat in the atmosphere relative to carbon dioxide"

Jan 1, 2008

By D. D. Harbuck

The U.S. Bureau of Mines recently identified a significant new source of scandium in an Oklahoma tantalum waste residue (approximately 0.24 pct Sc). Because scandium is a strategic and critical metal which the Department of Defense has classified for special consideration, the Bureau is researching methods of recovering scandium and associated metals from this and other process residues. A variety of operating parameters were evaluated to determine the best technique for recovering scandium. Testing showed that by sulfating the residue at temperatures as low as 150&apos; C for reaction times as short as 0.5 hr, over 94 pct of the scandium converted to a water soluble form. Solvent extraction using DEHPA selectively recovered 100 pct of the scandium from the water leach solution.

Jan 1, 1992

By M. Dattilo

Research has been conducted over the past three years using the composite anodes versus the lead alloy anodes. The Merrlin composite anodes have shown the improved performance in copper electrowinning versus the lead-calcium-tin anodes. Using the composite anodes a 100-150 mV reduction in anode overpotential has been observed versus the lead alloy anodes in sulfuric acid electrolyte. The composite coating has excellent corrosion inhibiting properties, and reduces or eliminates the formation of manganese oxide scale. Laboratory evidences indicate that, the use of these composite anodes enhances the process of electrowinning by improving the lead alloy corrosion resistance, lowers the electrode potential, reduces the need for cobalt addition, eliminates the anode cleaning, and reduces the generation of acid mist. Field tests are underway.

Jan 1, 1999

By Tetsuro Sakai

Home appliance recycling law was put into force in April 2001 in Japan. Specified kinds of home appliances, such as air conditioners, television sets, refrigerators and washing machines, should be recycled according to the law. Mitsubishi Materials Corporation (MMC) in cooperation with home appliance manufacturers is operating five home appliance recycling plants in Japan. MMC established complete treatment system of recyclable materials generating from home appliance recycling plants, which is formed by unique collaboration among home appliance recycling plants, copper smelter and refinery, and cement plants. Recyclable materials containing copper and precious metals are only handled and treated within the MMC group. By using this lock-in system, safe treatment and traceability of materials are guaranteed as 100% materials recycle.

Jan 1, 2008

By W. Petruk

The silver-rich cobalt-nickel arsenides ores of the Cobalt area in Ontario, Canada were mined for silver from about 1904 to 1985. The ores contained about 8 oz to 100 oz Aglt and about 1 wt% Ni and 2 wt% Co. They were processed by gravitational techniques, screening and flotation to produce separate silver and Fe-Co-Ni arsenide concentrates. The silver concentrate was smelted, and in some cases the arsenide concentrate was sold to custom smelters which recovered silver and other metals. The ores display a wide variety of textures and contain many minor and trace elements. This paper presents an evaluation of mineral characteristics that have a bearing on extractive metallurgy and smelting of this type of ore.

Jan 1, 1993

By He De-wen

The influence of coal desulphurization by fungus was experimentally studied. The present results suggest that fungus can effectively remove inorganic and organic sulfur in coal. The main factors that influence the desulphurization by fungus such as pH value, temperature, coal slurry concentration and coal granularity are studied by orthodox experiment and the optimal experimental conditions are as follows: pH value 6, temperature 45 C, coal slurry concentration 10% and coal granularity 100 m. Under the above conditions, fungus can remove up to 44.96 total sulfur and 54.87 inorganic sulfur within two days and their desulphurization rates will increase along with time. Compared to sulfolobas, desulphurization by fungus is steady and more effective and has the advantage of high speed.

Jan 1, 2006