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By Jiangtao Li, Zhongwei Zhao, Xingyu Chen, Xuheng Liu

In order to produce good quality ammonium paratungstate, Sn needs be removed efficiently from the tungstate processing solution. The nascent hydrous ferric oxide has excellent adsorption ability and is often used as an adsorbent to remove metal ions from aqueous solution. In this paper, nascent hydrous ferric oxide is used to remove Sn from tungstate solution. Through experimental, the effects of pH value, reagent amount of adsorbent, reaction temperature and reaction time on the Sn removal are investigated. The study shows that 98% of Sn can be removed effectively from sodium tungstate solution and only 2% of W is lost during process under the conditions of pH 9~12, reagent amount of Fe addition 40 times Sn amount, reaction time 30min and room temperature. As the Fe addition reaches 90 times of Sn concentration in the ammonium tungstate solution, 99% of Sn is removed and APT with zero level purity national standard is obtained.

Jan 1, 2014

By E. Bélisle, Christopher W. Bale, S. Petersen, C. Robelin, K. Hack, J. Melançon, G. Eriksson, A. D. Pelton, P. Chartrand, S. A. Decterov, I. H. Jung, A. Gheribi

The FactSage® package consists of a series of information, database and calculation modules that enable one to access pure substances and solution databases and perform thermochemical equilibrium calculations. FactSage was originally founded by process pyrometallurgists and has since expanded its applications to include hydrometallurgy, electrometallurgy, corrosion, glass technology, combustion, ceramics, geology, environmental studies, etc. With the various modules one can perform a wide variety of thermochemical calculations and generate tables and graphs of complex chemical equilibria and phase diagrams for multicomponent systems. This paper presents examples of recent and current developments in FactSage in areas of particular interest to Dr. David Robertson. These include both ferrous and non-ferrous processing, as well as solidification and refining simulation. The paper also includes reference to the Internet Fact-Web education package.

Jan 1, 2014

By Shengfan Zhou, XUEWEN WANG, Changjun Jiang, Mingyu Wang

In the process of extracting vanadium from stone coal by sulfuric acid leaching - P204 solvent extraction, Fe(III) can accumulate in the organic phase which reduces the extraction of vanadium. In order to eliminate the effects of the accumulation of iron, oxalic acid was used as the stripping agent to strip the Fe(III). The effects of oxalic acid concentration, phase ratio O/A, stripping time and shake velocity on the stripping of Fe(III) were studied. The results showed that the Fe(III) stripping rate can reach beyond 96% at the room temperature with 70g/L oxalic acid using an O/A of 2 at 160 rpm shake velocity for 20min. After 2-stage stripping, the concentration of Fe(III) in organic phase was 0.008g/L.

Jan 1, 2016

By Guangliang Wu, Dong-chang Huang, Xin-bin Liu

High temperature mechanical properties of 50Cr5MoV roll steel was investigated by Gleeble 1500 thermal simulator testing machine The morphology, composition and microstructure of fracture surface were observed and analyzed by OM, SEM and EDS The results are indicative of that, there are two brittle temperature zones of 50Cr5MoV roll steel at the temperature of 600°C~950°C and 1300°C~1450°C, respectively. The section shrinkage rate is less than 60% The fracture mode changes from mixed ones dominated by intergranular to toughness transgranular one with the increase of temperature at the range of 650°C~1300°C. The fracture is along the solid--liquid phase at the range of 1300°C~ melting point It is crucial to formulate the 50Cr5MoV casting technology, to prevent the cracks and improve the quality of 50Cr5MoV roll steel.

Jan 1, 2016

By Hongbo Zhao, Jun Wang, Wenqing Qin, Guanzhou Qiu, Xueduan Liu

Bio-hydrometallurgy technology was applied for the extraction of copper from the raw ores of Chambishi Mine in Zambia. A copper extraction of 93.29% was obtained for small scale column bioleaching within 63 days, while a copper extraction of 89.05% was achieved for large scale column bioleaching in 90 days, thus confirming the amenability of the raw ores for effective extraction via bioleaching. The bacteria were cultured in a 6-stage enlarge cultivation. The bacterial cultures with cell concentration of more than 1×108 cells/mL were added into a spray pond of sulfuric acid to be applied in the dump leaching, and a copper extraction of about 50% was achieved within 2 months. The production report revealed that the copper extraction increased by approximate 20%, and the acid consumption was reduced to around 35% as a consequence of adding the bacteria. The industrial demonstration of the bio-hydrometallurgy technique is now well established in Zambia, and further applications of bio-hydrometallurgy in both Zambia and Congo are currently in progress.

Jan 1, 2015

By Yuzhe Zhang, Xiaodi Huang, Xinli Wang, Bowen Li, Matthew Andriese, Jiann-Yang Hwang, Zhiwei Peng, Likun Li

With the development of the world, the waste tires have been a serious environmental problem. There are about 2 billion waste tires produced all over the world every year and about 500 million waste tires are produced in the United States. Most of the waste tires are land filled, which waste a lot of space. It takes hundreds of years to resolve the macromolecules of waste tire into the standard which does not pollute the environment. Microwave irradiation is a thermal processing way for waste tires decomposition. In this study, the relative dielectric loss factor of the tire at various temperatures was determined to understand the behavior of tires under microwave heating.

Jan 1, 2016

By Denise Crocce Romano Espinosa, Jorge Alberto Soares Tenorio, Amzy Tania Vallenas-Arevalo, Carlos Gonzalo Alvarez Rosario

Cyanideisatoxicchemicalusedinminingindustrytorecovergoldand silver in leaching process. Effluents containing cyanide can be treated by biore- mediation instead of physical and chemical processes which are often more expensive and less efficient. This study evaluated the capacity for free cyanide degradation of a Bacillus licheniformis strain previously isolated from an aban- donedgoldmine.First,bacterialgrowthinLBmediumthroughOD wasstudied. 600 Then,bacteriawasadaptedtogrowonalkalinemediumusingCAPSbuffertokeep pH10. Finally, cyanide degradation assays were performed using a 500 mgL −1 KCN pH10 50 mM CAPS solution. Free cyanide was measured using a polaro- graphicmethod.Temperatureinfluencewasevaluatedat27,32and37 °C.Results showedthat B. licheniformis was able todegrade 99% offree cyanide after 5 days of incubation and works better at 32 °C showing the strain potential for cyanide biotreatment in mining industry. (cid:1) (cid:1) (cid:1)

Mar 1, 2018

By S. N. Monteiro, J. Alexandre, L. G. Pedroti, D. P. Santos, B. C. Mendes, A. R. G. Azevedo, G. C. Xavier

The glass cutting industry is responsible for generating large quantities of waste, during the stages of cutting and polishing. The disposal of this material generates a cost to the company, thus looking for ways to repackage it, so there is the possibility of incorporating it into the adhesive mortar. The objective of this work is the characterization of waste and assessment of the properties of these mortars, fresh, and check the possibility of their use. As for the characterization, were carried out particle size testing, density and pozzolanic activity, for the fresh state were performed tests of air content, water retention consistency and entrained particular index. Were incorporated 0,10, 15 and 20% of the amount of sand. The results showed that the material on display ha spotential for use in adhesive mortar, with values within the limits stipulated by Brazilian standards.

Mar 1, 2017

By S. Chama, P. Chishimba, Tina Chanda Phiri, J. Machona, S. Parirenyatwa, G. Kaluba, Y. R. S. Hara, D. M. Musowoya

The investigation focuses on leaching of copper (2 wt%), cobalt (0.5 wt%) and iron (2.4 wt%) from complex tailings material from the Democratic Republic of Congo. The highest recovery of copper and cobalt into the leach solution were 78 and 10%, respectively, under direct leaching with sulphuric acid. Higher recoveries (90% for copper and 96% for cobalt) were attained when the material was pre-reduced with coal for 1.5 h in the temperature range of 700–950 °C. The increased recoveries were due to metallisation of all the copper and cobalt which is in the silicate matrix. The effects of pre-reduction temperature and sample to carbon weight ratios were analysed and found to be important in; (i) achieving high recoveries of copper and cobalt and (ii) decreasing the amount of iron in the leach solution. The samples were characterised by atomic absorption spectroscopy and scanning electron microscopy (SEM) techniques.

Mar 1, 2017

By Shigeru Ueda, Shin-ya Kitamura, Dong Jun Shin, Xu Gao

Steelmaking slag contains useful elements such as P and Mn. Generally, in the carbothermic reduction of slag, not only P but also Mn are reduced and a Fe–P–Mn alloy is formed. In this study, the possibility of the separation of Mn and P was investigated. A mixture of synthesized slag and graphite was heated at 1773 K, and the compositions of the separated slag and metal were analyzed. The results showed that with a decrease in basicity, the reduction of P was enhanced but that of Mn was suppressed. Thus, under an optimum condition, steelmaking slag was separated into a Fe–P alloy and a high MnO-containing slag. Although further investigation is necessary, the formed alloy and slag could be used as raw materials for fertilizers and Fe–Mn alloys, respectively. This paper elucidates the concept of this process and the results of the fundamental experiments.

Mar 1, 2018

By Michael Somerville, Paul Voigt, Chunlin Chen, Alistair Burrows

To date, many types of primary concentrate have been smelted using the ISASMELT™ technology, with annual smelting of copper concentrate alone exceeding 7 million tonnes. Most of this material could best be described as chalcopyrite concentrate, owing to the predominance of copper attributable to this single mineral. Chalcopyrite concentrates lend themselves readily to smelting with a fayalite slag, and producing a matte containing 55–65 wt% Cu. However, the ISASMELT™ technology also stands ready to meet future copper demand through the treatment of new types of concentrates containing relatively low iron and high silica levels. Various slag systems have been considered for direct-to-blister smelting. They have been evaluated computationally, using the MPE thermodynamic modelling package, and practically, at pilot scale. The lime-silica-iron oxide slag was found to have the lowest slag make, lower dissolved copper and hence lowest copper losses. Based on the outcomes of the modelling and pilot scale testwork a future smelter flowsheet has been defined, comprising a single ISASMELT™ direct-to-blister furnace, an electric slag cleaning furnace, and appropriately designed anode furnaces.

Mar 1, 2017

By M. X. Huang, Y. Z. Li

The titanium diboride (TiB2)-reinforced steel composite, designed for automotive applications, exhibits a combination of high isotropic Young’s modulus and low density as compared to existing advanced high strength steels (AHSS). The steel-based composite is produced by in situ precipitation of TiB2 particles during eutectic solidification followed by hot rolling, and its microstructure displays a homogeneous distribution of both large primary TiB2 and small eutectic TiB2 particles in the ferrite matrix. Instead of interfacial debonding, particle cracking is the primary mode of damage, revealing very high interfacial strength. To investigate the intrinsic interfacial strength, a hybrid method combining both nanoindentation and finite element analysis (FEA) was used. A micron-sized sample containing a single crystal TiB2 attached to the ferrite matrix was fabricated by focused iron beam (FIB), and was compressed using nanoindentation with a flat indentation tip. By combining the compression and FEA results, the interfacial strength was therefore determined.

Mar 1, 2017

By W. S. Hui, M. G. Silva-Valenzuela, H. Wiebeck, F. R. Valenzuela-Diaz, B. B. Michel

Biodegradable polymer microcapsules have been used as a control sustained release system with many applications. Studies reveal that the incorporation of nanoparticles improves matrix properties, even more so if the clay is modified. The objective of this work was to compare microcapsules of poly (succinate-co-butylenelactate) (PBSL) reinforced with Brazilian clay, composed of smectites and kaolinite, in its natural (MMT/K) and modified (O-MMT/K) forms. Nanocomposites and microcapsules were synthesized by emulsification-diffusion of solvent and solvent diffusion methods. Its characterization was then performed by scanning electron microscopy (SEM), stereo microscopy and wide-angle X-ray diffraction (XRD). The results reported corroborate that PBSL/OMMT-K form an intercalated montmorillonite and kaolinite nanostructure, capable of generating uniform spherical microcapsules with diameter values smaller than that of PBSL/MMT-K, reaching 5–10 lm. DRX indicates that there was a real change in the clay structure. The incorporation of modified clay showed an improvement in surface quality and the strength of microcapsules, making it possible to produce smaller sizes.

Mar 1, 2018

By Onuralp Yucel, Osman Halil Celik, Hakan Morcali

In this study, some experiments were performed for the dimensional control, pre-treatment, getting salt, metallic aluminum and aluminum oxide into the solution of 15 kg aluminum black dross obtained from a private company which recycles aluminium drosses. Water leaching experiments are done for removing salts and aluminum nitride. Temperature stirring speed, solid-liquid rate are investigated while water leaching experiments. Removing of AlN is provided at 25 °C at a rate of 42.48%, at 80 °C at a rate of 86.4%. Leaching experiments performed with NaOH. NaOH concentration and time was analyzed. Efficiency of including metallic aluminum into the solution is determined to be 98% approximately. Melting (fusion) experiments were performed with NaOH at high temperatures to include aluminum oxide in the structure of the remaining after dissolving process into the solution and after dissolving the resulting structures in water, efficiency of including aluminum into the solution is determined to be 85%.

Mar 1, 2018

By Wangzhi Zhou, Huasheng Chen, Bowen Li, Meng Liu, Mingsheng He, Long Zou

Steel slag is an inevitable by-product from a steelmaking furnace such as a converter, an open-hearth furnace or an electric arc furnace. The yield of steel slag increases with the sharp rise of steel production. Utilizing the slag effectively and comprehensively is one of the important tasks to promote the development of iron and steel industry in China in a sustainable and efficient way. In this study, hot-poured steel slag from a converter was used to prepare ceramics by mixing with fly ash, microsilica, and quartz. After heating at 1100–1200 °C, the ceramics were well sintered. XRD revealed that multiple crystalline phases coexisted in the glass-ceramics, and the main crystalline phases were diopside and anorthite. SEM observation indicated that there was a plate-columnar composite structure in the ceramics. Reaction mechanisms were discussed.

Mar 1, 2018

By Wufeng Jiang, Jiann-Yang Hwang, Suju Hao, Yuzhu Zhang

Lime was made by the calcination of limestone in a high pressure resistance furnace. The lime mineralogical phases and micro-morphologies was characterized by field emission scanning electron microscopy (FE-SEM). The lime activity degree was determined by acid-base titration, and the lime pore distribution was measured by mercury intrusion porosimetry (MIP). The results show that with the increase of calcination pressure, the lime activity degree is increased, and the lime develops a large pore structure. The desulphurization experiments were carried out in the induction melting furnace using active lime with different activity degrees as a desulfurizer. The results show that the desulfurization performance of lime is closely related to the activity degree. There is a strong positive linear relationship between the desulfurization rate and the lime ’s activity degree.

Mar 1, 2018

By Christine Wenzl, Christoph Wagner, Christoph Sagadin, Stefan Luidold

Corrosion mechanisms have been investigated between MgO refractory substrates and synthetic FeNi slags. The materials taken into consideration comprised a simple synthetically mixed slag with specific oxides of slags from a ferroalloy producer. The MgO refractory substrates with the slag specimens on it were heated in a hot stage microscope to two different characteristic temperatures, 1350 and 1650 °C. The experiments proceeded under a controlled gas atmosphere that simulates the relevant process conditions. The corrosion mechanisms of each system were determined by SEM analyses. The obtained results showed that slag corrosion is dominating with a pronounced partial dissolution of refractory. It was also observed that iron oxide present in the slag diffused into the coarse refractory grains forming the relative low melting magnesia wuestite. Finally,the comparison of these findings with those predicted by thermodynamic calculation (FactSage) indicated the corrosion mechanisms and draw implications for improving the refractory performance and lifetime.

Mar 1, 2017

By M. G. Silva-Valenzuela, H. Wiebeck, F. R. Valenzuela-Diaz, J. C. Arjona, S. H. Wang

Urea is the most used nitrogen fertilizer around the world being responsible for many environmental problems. Preparation of microcapsules from biodegradable polymer has been reported as a main system to sustain active substances, finding application in different areas. The objective of this work was to sustain urea in nanocomposite microcapsules of poly(3-hidroxybutyrate) (PHB) reinforced with a smectite Brazilian clay in its natural (MMT) and modified (OMMT) form. PHB/MMT and PHB/OMMT microcapsules were obtained by w/o/w emulsion. Characterization were performed by XRD and optical microscopy. Structural and morphological differences observed by XRD and optical microscopy shown that PHB/OMMT microcapsules are smaller than PHB/MMT microcapsules, with average size diameter ranging * 49 μm. Results indicate that PHB/OMMT microcapsules present more defects and fractures than PHB/MMT microcapsules.

Mar 1, 2018

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 Deepak Gupta, R. Kageyamat, J. W. Evans

"In electromagnetic casting, a liquid metal pool is partly supported by electromagnetic forces resulting from the interaction between induced currents and an alternating magnetic field. Stability of the metal surface is of paramount importance if the cast ingot is to be free from surface defects. Prior work by Garnier and Moreau had suggested that the magnetic field has no influence on the surface stability, but a more complete analysis at Berkeley suggested that surface perturbations are destabilized by the magnetic field once a critical magnetic field is exceeded. More recently we have employed a modified version of the software SOLA to compute the behaviour of a melt surface in the presence of an alternating field. The computed results support the theoretical analysis in predicting an unstable surface. Experimental work is now in progress to examine the stability of a mercury pool in the presence of an alternating field. Introduction and Previous InvestigationsElectromagnetic casting (EMC) is a technique widely employed in the aluminum industry to produce ingot for subsequent rolling. It is a ""continuous"" casting technique (illustrated in Fig. 1) producing ingots several meters high (and perhaps 1m by 2m in horizontal dimensions) at a casting speed of one or two mm. per second. The technology has gained acceptance because the metal is solidified without contact with a mold. Consequently the surface finish of the ingot is usually smooth and the ingot can be fed directly to rolling without machining, the surface (""scalping""). Scalping is necessary with alternative technologies (e.g., DC casting) where a mold is used. Consequently any disturbances that result in surface imperfections of EMC ingot are a serious matter. One type of imperfection is waviness on the surface of the ingot; a line drawn along the crest of a wave would run horizontally around the ingot. This imperfection may be caused by waves on the surface of the metal pool. As the waves reach the solidification line at the periphery of the metal they cause alternate outward and inward bowing of the meniscus at that point with attendant small (but significant) changes in ingot width. Elimination of building vibrations and similar disturbances minimize the occurrence of these surface waves but it is interesting to speculate whether there are disturbances of the metal pool that arise from the electromagnetic forces supporting the liquid metal. These forces are generated by the interaction of currents induced in the melt and the magnetic field produced by the current imposed on the inductor surrounding the melt. The present investigation has been concerned with whether the alternating magnetic field destabilizes the melt surface."

Jan 1, 1994