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By S. N. Monteiro, N. A. Cerqueira, E. B. Zanelato, J. Alexandre, M. T. Marvila, B. C. Mendes, A. R. G. Azevedo, G. C. Xavier

Mortar is a widely used building material and has its application in buildings in extremely vulnerable environments and susceptible to degradation, such as facades. The objective of this work was to evaluate the loss of mechanical resistance to compression and flexure and the loss of mass of the mortars with effluent sludge from paper industry, when exposed to saline environments. The specimens were done with 0, 5, 10 and 15% of incorporation in lime paste and subjected to saline mist equipment that sprays salt solution in cycles simulating natural degradation conditions using literature data. It can be concluded that mortars with a15%incorporation obtained a significant loss of mass and a decrease in their mechanical resistance, which impairs their use in civil construction and influence in other properties of the material, with a level of incorporation of 10% the results within Brazilian standards.

Mar 1, 2018

By M. A. Cocquerel

External process energy requirements and air pollution control regulations formulated to limit particulate and SO2 emissions are impacting on smelting and converting technologies and the corresponding process and secondary gas handling systems. This paper presents an overview of the different technical solutions used for cooling and dedusting the process gases in the different pyrometallurgical copper concentrate stages, including: drying, smelting, converting, slag cleaning and fire refining. The main principles of the process gas handling systems are presented &d a qualitative technical and economical comparison is discussed in relation to process changes, energy recovery and marketing or disposing of the various sulfur fixation by-products. Finally, a brief review of the methods for fixing sulfur contained in the process and secondary gases is presented.

Jan 1, 1999

By Ken Baxter

The Sepon Copper Project is located in Laos and has a mineable reserve of approximately 16Mt of ore grading 5% copper with minor gold and silver values. The deposit is a clay-hosted secondary copper mineral suite, predominantly chalcocitic in nature with associated pyrite. The current project design is based on the production of 60,000t/a of LME Grade A cathode by an acid leaching process followed by solvent extraction and electrowinning. Significant metallurgical testwork was conducted as part of the Definitive Feasibility Study (DFS) with process challenges identified and overcome at each phase of testing. Flowsheet configuration is geared to autogenously generating sufficient acid and ferric iron to meet gangue acid consumption and to leach the copper. The ability to maintain acid and ferric levels in the process liquors is strongly influenced by the proportion of pyrite in the ore presented to the autoclave. This paper will outline flowsheet development from preliminary variability testing to pilot plant and DFS design. The Sepon process solution seeks a balance between operability and capital/operating costs, and provides insights into the basic mechanisms influencing flowsheet selection for these ore types.

Jan 1, 2003

By Steven Wright

The extent and the rate of reduction of slags produced from the smelting of recycled lead batteries were investigated under laboratory conditions using graphite as reductant. Simultaneous reduction of PbO, Fe2O3, Sb2O3 and As2O3 occurred at temperatures of 1180 and 1200°C, with Sb and As reporting to the metal phase while the PbO content of the slag was above 2 wt%. Fuming of As from the metal occurred at lower concentrations of lead in the slag. Discard slags with low levels of As, Pb and Sb were produced. Arsenic levels were reduced to less than accurately measurable by ICP analysis, and Sb levels in the final slags were in the range of 0.1 to 0.2 wt%. The kinetic data obtained were analysed and compared with other measurements on lead oxide containing slags. The results showing a dependence of the reduction rate on the oxidation state and the basicity are consistent with other studies on well characterised industrial and. synthetic lead slags. These results indicate that when carbonaceous reductants are used, the rate of interfacial reactions play an important role in enabling the production of environmentally acceptable discard slags.

Jan 1, 1994

By Songlin Zhang

"The McCoy/Cove mine, located in Eureka-Battle Mountain trend of Nevada, is a gold and silver deposit. Case studies of recoverable reserve estimation for gold and silver were made using multiple indicator kriging and volume variance correction. The grade tonnage distributions of recoverable reserves were constructed and compared with the distributions defined by blast hole assays. Optimal pits were generated by Whittle 4D pit optimization package to analyze the impact of different processing recoveries at different economic cutoffs. The results were compared with ordinary kriging. The study indicates that the proposed method for multi-mineral recoverable reserve estimation is more accurate than kriging in tenns of grade and tonnage. The method of using recoverable reserves for pit optimization will maximize global reserve recovery and revenue, and is more efficient than condition simulation regarding computing power.ABSTRACT ONLY"

Jan 1, 1997

By Ross McClelland

This paper provides a technical overview on the installation and commissioning of the Ausmelt lead smelting, slag reduction and slag cleaning operations at the HZL Chanderiya site in India. It also discusses theoretical concepts behind the process practices currently in place at HZL.

Jan 1, 2006

By Sergei A. Degterov

A thermodynamic database for the slag, matte and liquid copper phases in the Cu-Ca-Fe-Pb-Zn-Si-O-S system has been developed for the ranges of compositions of importance to the production of copper. When used with the Gibbs energy minimization software and other databases of the F*A*C*T thermodynamic computing system, this database will permit the calculation of matte-slag-copper-gas phase equilibria that take place during copper smelting and converting. The calculations reproduce within experimental error limits all available experimental data on phase diagrams, activities of components, enthalpies of mixing, matte - alloy miscibility gap and tie-lines. The calculated solubilities of Cu in both S-free slag and slag equilibrated with matte are also in good agreement with experiment under all studied conditions, such as at SiO2 saturation, in equilibrium with Fe, Cu or Cu-Au alloys, at fixed oxygen or SO2 partial pressures and at different contents of Pb, Zn and CaO in the slag. Sulfide contents (sulfide capacities) of the slags are predicted within experimental error limits. The distribution of Pb and Zn among matte, slag, copper and gas has been calculated. The calculations are in good agreement with experimental data and predict the distributions under conditions which are difficult to study experimentally, such as at magnetite saturation or under various oxygen partial pressures and iron to silica ratios in the slag.

Jan 1, 1999

By R. A. Cockerell

This paper is concerned with the application of Advanced Process Control (APC) to copper smelting processes. A number of key issues relating to the application of APC, such as modelling for control, process dynamics and time delays, instrumentation and sampling, are discussed. A general methodology for the application of APC is then presented. Finally, three case studies are presented to demonstrate the benefits and efficacy of applying APC.

Jan 1, 1999

By Xiang Zhu

Xidagou is the largest waste water discharge channel of the Anshan Iron and Steel Complex (AISC) with average flow rate of 8000 cubic meters per hour, which is about 75% of the total effluent of the AISC. The waste water from Xidagou seriously polluted the Taizi River Basin. In order to meet the Chinese Class V Standard for Surface Water Discharge and the Standard for Recycled Industrial Water Reuse, with the aid of the World Bank, the AISC began the treatability studies in 1991. Based on the bench-scale test, the AISC carried out pilot-scale treatability studies on three different treatment processes and five different chemical coagulants for more than half a year in 1992. The study results show that the processes of primary sedimentation- chemical mixing and flocculation-secondary sedimentation-filtration can meet the requirement and that PFS and PAM are effective and economic chemical coagulants.

Jan 1, 1994

By Wenxuan Xu, Shusen Cheng, Guolei Zhao

Nowadays,the flow pattern and stress distribution o burden material sin blast furnace has been widely calculated by discrete element method. In this study, the influence of operation conditions such as ore batch, the root position of cohesive zone and the slope of cohesive zone on the flow pattern and stress distribution of burden materials in blast furnace were investigated. The normal stress of burden materials in deadman increases with the increase of ore batch, but the normal stress of burden materials in deadman decreases with the increase of the root position of cohesive zone and the slope of cohesive zone. The average descending velocity of burden materials increases with the increase of ore batch, but the average descending velocity of burden materials decreases with the increase of the root position of cohesive zone and the slope of cohesive zone.

Mar 1, 2017

By M. A. Kader, M. A. Islam, P. J. Hazell, M. Saadatfar, J. P. Escobedo, A. D. Brown

The dynamic pore collapse mechanisms and energy absorption capacity of closed-cell aluminium foams subjected to low velocity impacts have been investigated. Impact experiments were carried out using an instrumented drop-tower with two impactor geometries: a 50 mm square flat steel impactor to investigate pore collapse mechanisms and a 20 mm diameter hemispherical steel impactortostudy indentation resistance.X-ray computedtomography was utilized to generate views of the deformation field within the impacted specimen. The results show that the strain rate and incident impact energy influence the energy absorption capacities of closed-cell aluminium foams. Furthermore, damage initiation, propagation and cell collapse mechanisms under drop weight impact have been elucidated.

Mar 1, 2017

By R. S. Tahautdinov, A. N. Posazhennikov, V. V. Bastrygin

"The Bakal (South Ural, Russia) deposit of iron ore bearing iron carbonate (siderite) with the capacity of more than 1 billion tones belongs to the MMK. This ore cannot be fully processed via blast furnace technology because of high content of MgO. According to the investigations carried out in the USA and Japan in 1999-2004 the ITmk3 (Ironmaking Technology mark three) RHF technology is a breakthrough in Ironmaking. Four iron ore types (hematite, magnetite, high and low Al2O3/SiO2) were tested. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from iron carbonate bearing ore via the ITmk3 by means of the lab scale testing. Samples of iron ore and carbon reductant were chemically and physically analyzed. Green pellets were processed via a lab tube furnace to simulate RHF conditions. The nuggets and slag were chemically analyzed. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities in 1996 [1]. After pilot testing at Kobe Steel’s Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics has committed to building the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota). Only 4 iron ore types (hematite, magnetite, high Al2O3/SiO2 and low Al2O3/SiO2), as well as 4 coal types with range of volatility, ash and fixed carbon were tested. Results were consistent with nugget characteristics confirming ITmk3’s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from iron carbonate bearing ore with high content of MgO has been done. Such kind of iron ore is restricted for charging into the blast furnace due to contamination of MgO. The reason for restriction is the limitation of load of MgO in the blast furnace. If a lot of MgO enters the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace."

Jan 1, 2011

By Frank R. A. Jorgensen

Flash smelting is used to smelt a large proportion of the world's copper and nickel and some lead/zinc concentrates. Understanding the factors controlling the ignition of these concentrates is an important consideration in designing burners and maximising the throughput of the flash smelting process. The literature on the subject is briefly reviewed and techniques for the measurement of ignition temperature discussed. The mineralogy of the concentrates and the role of thermodynamics and phase diagrams in interpreting and predicting ignition behaviour are emphasised and applied to interpreting results obtained on a nickel concentrate.

Jan 1, 2002

By R. P. King

The linear intercept distributions provide unambiguous and accurate characterizations of the texture of mineralogical materials. The relation between the measured linear intercept distributions and the spatial correlation function is shown to be given by: in the Laplace Transform domain. The linear intercept distributions of the two phases in a low- grade chromite-serpentinite ore were measured. and the spatial correlation functions for both phases were evaluated using the above relation. The correlation functions are the primary relations for integral geometric models of mineralogical texture and this work demonstrates the relation between the 10 stereological model and the 3D integral geometry model for mineral liberation.

Jan 1, 1991

By Varadajan Seshadri

Torpedo cars have been extensively used for pig iron desulfurization although its geometry is not considered to be ideal as far as mixing and mass transfer are concerned. Complications arise from scaffolds formed through aggregation of flux, slag and pig iron during operation. Following industry demand a 1:6 torpedo car physical model was operated to assess the optimum refining conditions for pig iron desulfurization. Similarity between the model and prototype were established through Froude and turbulent Reynolds criteria. Mixing times were evaluated by pulse tracer addition and the kinetics of metal/slag interactions were assessed from experiments investigating iodine transfer from kerosene to water. The influence of parameters such as level of metal, gas flow rate, lance penetration, lance orientation, presence of scaffold were evaluated. Mixing times were found to be shorter than regular desulfurization time and also not very sensitive to scaffold presence. Scaffold contributes to the reduction of the useful volume only. Mass transfer at the permanent reactor is more effective when the torpedo is operated at its full capacity. The experiments also highlight the dominance of the transitory reactor as compared with the permanent reactor.

Jan 1, 2006

By S. Ikenobu

This paper describes a method for processing high-silicate zinc concentrates by hydrometallurgical zinc refining. Silica in concentrates reacts to form zinc silicate during roasting. The zinc silicate readily dissolves and slowly precipitates in sulfuric acid solutions during leaching. However, if proper operating parameters are not maintained, the colloidal silica may form an unfilterable gel. That is, according to the investigation results obtained, the silica concentration in the reactor has to be maintained at 5 g/1 or less (preferably 2 g/1 or less) by promoting the precipitation reaction. The proposed method has made it possible to precipitate silica in a form having excellent solid-liquid separation characteristics, without the need for facilities having a high filtration capacity, and to maintain a low silica concentration in the reactor by feeding a composition containing pre-adjusted silica contents.

Jan 1, 2000

By A. Mejias, M. A. Garcia, G. Diaz

During 1997 and 1998 two successful zinc feasibility studies, Skorpion and Sanyati, were carried out by Tecnicas Reunidas based on the modified ZINCEX® technology. The technical viability of each project was proved during more than 600 h of continuous running in a pilot plant. The Skorpion zinc project would recover 150,000 t SHG Zn/y from an oxidized zinc ore of a Namibian mine. The economical study showed that the plant would have the lowest production costs in the world. The Sanyati zinc project would treat a bleed from an existing copper refinery in Zimbabwe to recover 5,000 t SHG Zn/y. In the first case the electrowinning cellhouse was supplied by Union Miniere and in the second by Tecnicas Reunidas. This article highlights the pilot plant results and the advantages of the proposed process over conventional zinc production practices.

Jan 1, 2000

By E. V. Redin

"The Bakal (South Ural, Russia) deposit of iron ore bearing iron carbonate (siderite) with the capacity of more than 1 billion tones belongs to the MMK. This ore cannot be fully processed via blast furnace technology because of high content of MgO. According to the investigations carried out in the USA and Japan in 1999-2004 the ITmk3 (Ironmaking Technology mark three) RHF technology is a breakthrough in Ironmaking. Four iron ore types (hematite, magnetite, high and low Al2O3/SiO2) were tested. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from iron carbonate bearing ore via the ITmk3 by means of the lab scale testing. Green pellets were processed via a lab tube (chamber) furnace to simulate RHF conditions. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities in 1996 [1]. After pilot testing at Kobe Steel’s Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics has committed to building the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota). Only 4 iron ore types (hematite, magnetite, high Al2O3/SiO2 and low Al2O3/SiO2), as well as 4 coal types with range of volatility, ash and fixed carbon were tested. Results were consistent with nugget characteristics confirming ITmk3’s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from iron carbonate bearing ore with high content of MgO has been done. Such kind of iron ore is restricted for charging into the blast furnace due to contamination of MgO. The reason for restriction is the limitation of load of MgO in the blast furnace. If a lot of MgO enters the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace."

Jan 1, 2012

By Mark Cross, Diane McBride, Nick Croft

Extractive metallurgical processes rate amongst the most complex from the perspective of computational modeling. They typically involve multi-phase and multi-component fluid flow in very complex geometries, heat transfer driven by a number of interacting phenomena, solidliquid- gaseous phase change and mass transfer together with complex thermodynamics and associated chemical reactions. Beyond the model building itself, key challenges have always involved being able to identify the phenomena present together with interactions to characterize processes and experimental laboratory and plant data to parameterize the arising models – it is in this milieu, which require considerable process understanding and subtlety of thought, that David Robertson has made his contributions. We will review the achievements, over the last couple of decades, in computational modeling of extractive metallurgical processes and address some of the remaining challenges to enable simulation based process design, as we move through the 21st century.

Jan 1, 2014

By Ibrahim Yusufoglu, Cem Kahruman, Sedat Ilhan, Ahmet Orkun Kalpakhi

"Scheelite is the main raw material in tungsten production. In hydrometallurgical processes, extraction of tungstate ions into solution is very important. During the leaching of scheelite in oxalic acid solutions, tungsten dissolves as a chelate complex. Scheelite includes impurities along with calcium tungstate. Determination of the dissolution of these impurities is important in the subsequent tungsten production stages. In this study, scheelite was dissolved in oxalic acid solutions and the dissolution of impurities was investigated. The quantities of dissolved impurities were determined by ICP - OES and characterization of the undissolved impurities in the leach residues was carried out by SEM - EDS analysisIntroductionScheelite and wolframite ores are used for the industrial production of tungsten. Both ores are dissolved in acidic or basic solutions, and ammonium paratungstate is obtained as an intermediate product. Prior to crystallisation of ammonium paratungstate, all the impurities must be removed. Among these, Fe, Si, P, Mn, Mg and Mo are classified as ""harmful"" elements and different methods are used for their removal [1]. During purification, solvent extraction, ion exchange, etc. methods are used.Potashnikov et al. [2] studied the dissolution of scheelite in acidic solutions and the effects of stirring speed, temperature and oxalic acid concentration on the dissolution kinetics.There are no works in the literature about the removal of impurities from scheelite ores in oxalic acid solutions. Therefore, the aim of this work was to investigate the dissolution mechanisms of impurities during the leaching of scheelite in oxalic acid solutions. The effects of temperature and oxalic acid concentration on the dissolution were also investigated. In addition, the characterization of the impurities which were not dissolved was studied."

Jan 1, 2012