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By R. Schuhmann

The thermodynamic data and calculations which underlie the design of the Q-S process for coppermaking are summarized. The efficient production of crude copper and slag of low copper content in a single con¬tinuous converter requires the establishment and control of gradients in oxygen activity and other physico-chemical variables throughout the reactor. These gradients are established by stagewise introduction of oxygen and solid feed materials to provide: (a) flash oxidation of sulfides above the bath, utilizing the great bulk of the oxygen, (b) conversion of high grade matte or white metal to crude copper by bottom blowing with restricted bath turbulence, (c) close approach to equilibrium staging of converting and deconverting reactions along the length of the slag layer, from a maximum oxygen activity near the metal discharge end to a minimum at the slag discharge end, and (d) completion of slag cleansing by deconverting. In terms of the Phase Rule, the Q-S process involves a system with a minimum of 5 components (Cu, Fe, S, O, and SiO2) and several liquid, solid, and gaseous phases. Accordingly, basic data from previously reported studies on simpler systems are utilized to prepare an equilibrium diagram for the 5-component system and to generate a quantitative thermodynamic model for the Q-S process. This model shows in particular the ranges of oxygen activities (measured by equivalent CO2/CO ratios) involved in the Q-S process and the relations of oxygen activity to temperature and other important physico-chemical variables of coppermaking.

Jan 1, 1976

By J. D. McCain

Magma's San Manuel smelter has adopted new operating techniques resulting in 21% increased productivity and 87% reduction in lost time accidents. Reverberatory furnaces were converted to coal firing from expensive natural gas and fuel oil. Slag and matte flow problems and safety were improved by implementing hydraulic slag stopping and matte tapping machines. Coordination of furnaces, converters and acid plant was improved by using a computer-aided converter controller/scheduler function. Manual mudding of converter lips after each collar pull was replaced with a gunning system for coating the mouth castings. One converter punch car was automated using robotic technology. An automatic anode take-off was installed with fewer moving parts and a mechanism for ear twisting one cell contact. Anode copper refining was improved by replacing propane/hydrogen mixtures with high pressure/velocity natural gas tuyeres. Improved converter scheduling increased acid plant production 43% with more autothermal operation time. Six dedicated computers/microprocessors are utilized for automation, data acquisition, process monitoring and on-line air quality information for the Supplementary Control System.

Jan 1, 1983

By Pavol Loderer

Mineral froth pumping utilising centrifugal slurry pumps is a major engineering challenge for the end users and pump manufacturers due to the undesirable outcome of unstable pump performance. Most of these challenges occur due to incorrect pump selection and suction tank design. The traditional approach is to oversize the pump for pumping mineral froth. New horizontal slurry froth pump designs offer opportunities to improve the mineral froth with challenging (high) Froth Volume Factor while maintaining high efficiency, long wear life and stable pumping performance. This paper examines the flotation process in detail and how froth pumps are designed to handle this arduous process.

By V. Madhusudhan Rao

Fly ash is a finely divide non ? combustible material obtained as a by ? product of coal combustion. It is a major by ? product of coal based thermal power stations. Until recent past it was considered as a waste and highly polluting material. However its formation can only be minimized by using suitable technology in the boilers. In recent past it is found that Fly ash has many end uses and it has proven itself to be a potential construction material. But the suitability of fly ash for various applications largely depends on the amount of unburned carbon, which is turn depends on the firing method. Fly ash samples from various power plants existing in India using a fluidized bed method and pulverized bed were analyzed and a comparison of these two firing methods was carried. This paper deals with the compositional requirements for fly ash used for the fabrication of insulating doors using AAC (Aerated Autoclave Concrete) and the methods employed to make fly ash suitable for this purpose. It also includes the latest ?U? beam technology for effective fly ash recycle. If the by products of coal combustion from power plants like fly ash as the paper stresses are utilized properly, it is not an exaggeration to say that power generation is possible with absolutely zero cost.

Jan 1, 2006

By I. D. Reznik

The flowsheets of converter matte production from sulphide copper - nickel and oxide nickel ores on Severonickel and Yuzhuralnickel integrated ,;corks are given. The cobalt behaviour in electrosmelting and autogenous ore smelting, converting and converter slag cleaning is observed. A list of acticles published in the 80 th is given.

Jan 1, 1993

By Shunsuke Yagi

A surface alloying technique was investigated using alternating pulsed electrolysis in an aqueous solution containing a single metal component for the formation of an Fe-Cr layer on an iron substrate. In the process, the iron substrate was dissolved during each anodic polarization of the pulsed electrolysis, providing iron ions in the vicinity of the substrate, while the Fe-Cr alloy was electrodeposited during subsequent cathodic polarizations. A bright, flat, and crack-free Fe-Cr layer with a composition gradient was obtained using a solution containing a trivalent chromium component and a complex forming agent together with some supporting or buffering salts.

Jan 1, 2006

By O. A. Bascur

Applying the latest information technologies in mining and metallurgical complexes has become a serious challenge to management and technical teams. Emerging component design is changing the way the user relates to the desktop. Connectivity between mining and metallurgical process operations and their business systems has become a reality. Expanded use of plant information on the desktop is a standard tool for revenue improvement, cost reduction and adherence to production constraints. The industrial component desktop support access to information for continuous improvement and innovation by staff personnel and engineers. Collaboration between groups enables the implementation of an overall process effectiveness index based on losses due to equipment availability, production recovery and quality rate. The integration of information from mining, mineral processing and metallurgical performance monitoring increases production efficiency, even when many elements cannot be measured directly. Three case studies of large mining/metallurgical complexes are highlighted.

Jan 1, 1999

By L. M. Luckevich

Gypsum is a product from the neutralization of sulfuric acid by lime or limestone. This paper will discuss specifications for gypsum used in wallboard, cement and agriculture and the factors affecting its utilization potential. Process conditions during the neutralization which enhance or inhibit utilization potential will be included. In addition, this paper provides a technical and economic perspective of the gypsum industry in North America with a view to the factors affecting the utilization of synthetic gypsum in traditional applications. Current production and consumption of natural and synthetic gypsum in Nonh America are described and the impact of their differences on utilization options are discussed.

Jan 1, 1996

By Yuanbo Zhang, Zhixiong You, Zijian Su, Bingbing Liu, Guanghui Li, Guang Yang, Tao Jiang

Sodium stannate is widely used in the electroplating and tin alloy industry. But the traditional processes for sodium stannate production are characterized by long flowsheet, high production cost and strict requirement for the equipments, etc. In this study, a novel process for sodium stannate preparation from cassiterite concentrate and sodium carbonate via roasting in CO/CO2 mixed gas then followed by leaching was developed. The effects of roasting parameters on the Sn leaching efficiency were conducted. A Sn leaching efficiency of 77.2% was obtained under the optimal conditions. Sodium stannate (Na2SnO3·3H2O) with a purity of 95.8% was produced by the new process, which is better than that specified for the industrial first-grade product.

Jan 1, 2014

By Yuanbo Zhang, Bin Xu, Guanghui Li, Xiao Kang, Chen Liu, Tao Jiang

Iron-bearing dusts, containing valuable constituents such as Fe, CaO, MgO, C, etc., are generally utilized as raw material in iron ore sintering. However, the dusts characterized by low granulating and refractory performances always lead to negative effects on sintering indexes. As we know, the innovative process named composite agglomeration process (CAP) has a series of advantages compared to traditional sintering process (TSP). In CAP, part or all of the iron-bearing dusts is made into green pellets with 5-15mm in diameter, while the rest of iron-bearing dusts and all of the other fine ores is granulated after mixing with fuels, fluxes and return fines. Compared with TSP, CAP could increase the ratio of iron-bearing dusts from 5% to over 20%. Meanwhile, the yield, ISO tumbler index and productivity reached 75.82%, 65.13% and 1.531t·m-2·h -1, respectively.

Jan 1, 2015

By Lætitia H. Delmau

SXFIT is the latest in a series of programs developed in our group to model solvent extraction systems of increasing complexity. SXFIT permits the user complete freedom to define the constituents from which the composition of each phase is to be specified in the data and from which all species of a model for a system are assumed to be formed. Activity coefficients in the nonaqueous and aqueous phases, water activity, apparent molar volumes of aqueous species, and solution density needed for the conversion of concentration from the molarity to the molarity scale are all taken into account by the program. Several extraction systems relevant to nuclear-waste treatment were modeled successfully using this program. As an example, the cesium extraction efficiency of the CSSX process chosen by the USDOE for cesium removal from high-level waste stored at the Savannah River Site can be predicted correctly for varying feed composition.

Jan 1, 2003

By Jan Petter Maehlen

Solid H-absorbing materials are in focus of ongoing R&D to offer viable solutions for the hydrogen storage and supply systems aimed on use of hydrogen as energy carrier for automotive transportation. Low operating pressures, combined with high gravimetric and volumetric efficiencies, together with fast kinetics of hydrogen release at ambient temperatures (providing conditions for a low energy loss due to decomposition), are the most important features of the ?ideal? H storage material. Hydrides of the light elements are the only possible candidates to build systems with an overall efficiency similar to those accommodating liquid or compressed (700 bar) hydrogen. One promising material from this point of view is aluminium trihydride, alane AlH3 with a gravimetric storage capacity of 10 wt.% H. This work was focused on studies of the crystal structure and thermal decomposition of alane by application of powder synchrotron X-Ray diffraction.

Jan 1, 2006

Thallium is a very minor element found in lead ores. It's behaviour during lead smelting has recently become of much greater interest due to the effects it had on the health of waste heat boiler maintenance contractors at a Canadian smelter. In this paper the behaviour of thallium in both traditional and direct lead smelting processes will be examined using computational thermodynamics techniques. Yazawa and his coworkers have made extensive use of computational thermodynamics to examine and illustrate pyrometallurgical processes. It has been shown that thallium behaviour during smelting is strongly influenced by the extent of oxidation of the lead concentrate and by the presence or absence of chlorine in the charge. The condensation behaviour of thallium species in the waste gas handling system was also modelled and it has been confirmed thallium-rich deposits can form at the high temperatures prevailing in waste heat boilers.

Jan 1, 2003

By Mukesh Jain

The liquor from potroom wet scrubbers is treated with lime to precipitate the soluble fluorides. The solids after filtration, referred to as scrubber mud, contain in addition to calcium fluoride, alumina, carbon, tars including polyaromatic hydrocarbons (PAH), cryolite and pachnolite and are considered hazardous. This communication deals with the pilot plant scale calcination of scrubber mud with a rotary kiln to obtain non-hazardous fluoride raw materials. Air classification was performed to separate the mudinto aluminarich andcalcium fluoride rich fractions which were then calcined. With proper control of calcination parameters and addition of lime, the carbon and tars were destroyed and hydrogen fluoride emissions were controlled. The calcined products could be used in the steel indusny as a fluxing agent or as a substitute for fluorspar in the production of aluminum fluoride.

Jan 1, 1994

By Fuxing Yin, Akira Sato, Yoshiaki Ohsawa, Kohji Kawaharai

"INCRAMUTE alloy (nominally 45Mn-53Cu-2Al wt. %) has a specific damping capacity as high as 0.4, through a solid-solution and aging treatment. The damping behavior of the alloy is highly temperature-dependent and shows a peak near room temperature. The inadequate strength in the high damping condition restrains the practical application of the alloy, as structural components. Ferromagnetic MnB particles are dispersed in the alloy during induction remelting the matrix alloy in an argon atmosphere. Surface modification of the MnB particles by mechanical alloying (MA) and suitable control of the addition process cause a homogeneous distribution of MnB particles in the alloy. In the composite containing 2 wt. % MnB particles, temperature dependence of damping capacity is improved, and higher damping capacity is still retained in the temperatures over 60 °C. Meanwhile, the Young's modulus and tensile strength were also increased by about 20%. The roles of the MnB particles in improving both damping behavior and mechanical properties were also discussed.IntroductionMany viscoelastic materials, such as rubbers, polymers and plastics, have the superior ability to damp vibration and noise. However, in the applications as structural materials the high damping capacities of materials are pursued upon the satisfactory mechanical properties, especially those at elevated temperatures. Damping alloys are finding more and more applications in structures where noise and vibration ·should be ·eliminated. Specific damping capacity (SDC), defined as the ratio of the energy dissipated to the maximum vibration energy stored per cycle, is usually used to evaluate the damping capacity of alloys. INCRAMUTE damping alloy, developed by the International Copper Research Association, Inc., has a nominal composition of 45Mn-53Cu-2Al in weight percent. The high damping· microstructure of this alloy is obtained through the solution treatment at 820 °C followed by a water quench and aging at 400°C for 10 hours followed by cooling to room temperature [1]. With the heat treatment, a SDC peak ·vs. temperature of as high as 0.4 was observed in the alloy at the strain amplitude of about 10-3 while a tensile strength of about 500MPa was sustained."

Jan 1, 2000

By Michael J. McGuire

Rostoker, Inc. has developed a process to smelt solid hazardous/non-hazardous inorganic wastes. Near seven hundred experiments were performed. Actual industrial wastes as well as reagent grade chemicals were used. By mixing a multiplicity of these wastes to proper formulations, then furnacing them, it was determined that saleable end products could be reclaimed; metal, fume and slag. The slag, due to its siliceous structure was tested to be leach resistant (40 CFR). This formed the essence of our patent, #5,180,421 "Method and Apparatus for Recovering Useful Products from Waste Streams". What is unique is that a HTMR (High Temperature Metal Recovery) process has been developed that can treat a multiplicity of wastes within the same furnace. The discussion will include a list of waste streams we have treated, details of proper waste formulation and experimental results.

Jan 1, 1994

By Satu Strömberg

Four different nickel concentrates were oxidized in a laboratory scale laminar flow furnace in simulated flash smelting conditions. The major nickel- and iron-bearing minerals in the con- centrates were pentlandite, violarite, gersdorffite, and pyrite and pyrrhotite, respectively. Thermal decomposition, ignition and oxidation behavior of nickel and iron sulfides were examined by using optical and scanning electron microscopy. General reactivity of the concentrates was monitored with sulfur removal which was most effective in violarite-based concentrate. Pentlandite-concentrates needed higher experimental temperatures for complete desulfurization and gersdorffite-based concentrate contained 5 - 10 % of the original sulfur even in the most oxidizing conditions studied (1 100°C, 50 vol-% 02). The reactivity of the iron minerals was found to depend on the other minerals present in the concentrate. In this paper, the observed re- action products and mineralogical changes are presented and preliminary conclusions of possible reaction mechanisms of nickel-bearing minerals are discussed.

Jan 1, 1997

Thallium is a very minor element found in lead ores. It's behaviour during lead smelting has recently become of much greater interest due to the effects it had on the health of waste heat boiler maintenance contractors at a Canadian smelter. In this paper the behaviour of thallium in both traditional and direct lead smelting processes will be examined using computational thermodynamics techniques. Yazawa and his coworkers have made extensive use of computational thermodynamics to examine and illustrate pyrometallurgical processes. It has been shown that thallium behaviour during smelting is strongly influenced by the extent of oxidation of the lead concentrate and by the presence or absence of chlorine in the charge. The condensation behaviour of thallium species in the waste gas handling system was also modelled and it has been confirmed thallium-rich deposits can form at the high temperatures prevailing in waste heat boilers.

Jan 1, 2003

By R. Padilla

A thermogravimetric study has been conducted to follow the decomposition and volatilization of arsenic from enargite concentrate in nitrogen and slightly oxidizing atmospheres. Temperature has a large effect on the rate of volatilization of arsenic. Fractional volatilization of arsenic as high as 98% were obtained in less than 60 min at 650°C in nitrogen atmosphere, while in slightly oxidizing atmosphere the same volatilization could be achieved in 30 min. It was found that arsenic volatilizes as sulfide in nitrogen atmosphere and as 4xture of sulfide and oxide in atmospheres containing 1% oxygen. By using the pore blocking and the first order kinetic models, apparent activation energies of 213 and 200 kJ/mol for the temperature range of 780 - 900 K and 205 and 184 kJ/mol for the temperature range of 900 - 985 K were determined for enargite and copper concentrate, respectively.

Jan 1, 1997

By Wenjie Zhu

Chromite ore processing residue (COPR) is a hazardous waste containing high concentration of chromium. We describe here a pioneer trial of detoxification of COPR in column reactor with an indigenous chromate reducing bacterium Leucobacter sp. Ch1, which showed high chromate reducing ability at high pH. Under the optimum conditions, at 30°C and pH 10.0, pH of leachate decreased from 10.3 to 8.3, and Cr(VI) concentration in solution decreased to zero mg L-1, and 76.4% of Cr(VI) was removed from COPR samples. The leaching toxicity of detoxified residue was 1.1 mg L-1 that was lower than national standard of China.

Jan 1, 2008