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By Feng Wang, Guojing Shi, Yangyang Xie, Zizong Zhu, Qiang Wu

The coal chars from northwestern part of China are characterized with high reactivity and low strength after reaction. Four type of coke-making coals selected from northwestern part of China were studied by proximate analysis, ultimate analysis, vitrinite reflectance analysis, and FTIR with curve-fitting analysis to obtain information on their chemical composition and chemical structure. The results show that the studied coals have relatively high values of final contraction of coke residue index (x) and relatively low values of maximum thickness of plastic layer (y) and average vitrinite reflectance. Based on the curve-fitting analysis of FTIR spectra, the aliphatic carbon (Cal), the aromatic carbon (Car), and the molecular structural parameters such as CH2/CH3, fa, Hal/Har, and (R/C)u are determined. The results of curve-fitting analysis indicate that the studied coals are characterized by a large amount of oxygen-containing functional groups and aliphatic side chains.

Mar 1, 2018

By M. A. H. Shuva, M. A. Rhamdhani, G. A. Brooks, S. H. Masood, M. A. Reuter

Ferrous-calcium-silicate (FCS) based slag has been used in the copper industry over the last two decades. The FCS slag has also been used in a secondary copper processing such as in black copper smelting which has different operation conditions compared to that of typical primary copper processing. In the process, a variety of copper bearing scraps from sources such as industrial waste, consumer waste and electronic waste (e-waste) are used. The valuable metals in these sec- ondary resources are distributed in different phases during the process. Understanding the behaviour of the valuable elements at the relevant conditions is vital for optimizing the process and to maximize the recovery of the elements. In this study, we investigated the structure of Ge-containing FCS-based slag at different conditions (oxygen partial pressure and temperature) using Fourier-Transform Infrared (FTIR) spectroscopy to explore the effect of the polymerization on the behaviour of the valuable element Ge in the slag. It was found that experimental parameters significantly in fluence the slag structure, and therefore, the partitioning of Ge in the slag. A correlation between the distribution ratio of Ge and the slag structure has developed in the current study.

Mar 1, 2018

By Liugen Sun, Xingming Jiang, Weijiao Yang, Yihang Hu, Yongqiang Yang, Hua Wang

During the past decades, cyclone electrowinning (CE) has been regarded as a novel separation technology, which can be used for direct electrowinning of metals from low concentration solution. Recently, CE was proven effective for the treatment of antimonic gold concentrates. The experimental results of cyclone electrowinning of antimony show the current efficiency increases from 43.8 to 72.2% with the increasing current density (from 254.8 to 647.3 A/m2), and on the other hand, power consumption per ton antimony decreases from 6100 to 4200 kWh with the aforementioned increasing current density. The grade of the obtained cathode antimony could reach 98.6%. Compared with the traditional electrowinning using parallel-board electrodes, the economic profit of CE was 33.1% higher attributed to the high current efficiency of CE. In addition, CE could adapt to high current density. All these characteristics indicate the CE method can be implemented commercially for processing antimonic gold concentrates.

Mar 1, 2018

By Qingguo Xue, Jingsong Wang, Siyang Long, Jun Zhao, Haibin Zuo

In order to effectively use of low rank coal, the thermally dissolve coal (TDC) was extracted from four kinds of low-rank coals by N-2-methyl-2-purrolidinone (NMP) at high temperature and high pressure. The structures of thermally dissolve coal and residues were characterized by element analysis, FT-IR spectra. The effects of temperatures, coal rank, solid-liquid ratio and extraction time on the extraction yields of TDC were studied, respectively. Moreover, the extraction mechanism of TDC at mild conditions is proposed. The results show that the ash contents of TDCs from four raw coals are significantly lower than that of raw coals, and the volatile contents and H/C are significantly improved. For KL coal, with the increase of temperature, the extraction yield of KL-TDC is improved evidently from 33.75% to 56.25% and the ash content is decreased from 0.57% to 0.49% at 350 °C.

Mar 1, 2018

By Pier-Lorenzo Solari, Philippe Moisy, Michel Schlegel, Stephane Pellet-Rostaing, Eric Mendes, David Bengio, Richard Husar, Thomas Dumas

Ionic liquids (ILs) are molten salts composed of an organic cation that are liquid below 100 °C. They demonstrate unique physico-chemical properties such as good conductivity, negligible vapor pressure and non-flammability. As a consequence, they are often regarded as green solvents and could become an alternative to the use of both high-temperature molten salts and volatile organic solvents in rare-earth elements processing and recycling. The diversity of interactions existing in an ionic liquid allows the solubilization of both polar and apolar compounds. Moreover, coordinating functions on their composing ions can lead to stabilization of some species. For instance, in non-aqueous media, europium exists in the (II) oxidation state which is not stable in aqueous solutions. Understanding the mechanism of Eu(III) electrochemical reduction to Eu(II) and the stabilization of Eu(II) species in IL media could be of major interest for the development of innovative recycling processes. Using transient electrochemistry and UV-Vis spectroscopy we could get valuable information on the redox behavior of the Eu(III)/(II) couple in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIm][NTf2]). Reduction of Eu(III) to Eu(II) and stability of Eu(II) was also studied thanks to a XAS-spectroelectrochemistry set up used to follow in situ the evolution of the XANES spectrum around the L3 edge of Eu during electrolysis.

Mar 1, 2018

By Wagner Aldeia, Duclerc Fernandes Parra, Danae Lopes Francisco, Ademar B. Lugão, Lucilene Betega de Paiva

The inorganic nanotube halloysite (HNT) is a promising type of natural occurring filler for polymers. Its characteristics, such as high aspect ratio (10–50), small size, and high strength (elasticmodulus—140GPa) suggest that HNT shave a potential use in high-performance polymer nanocomposites. Compared to other nanoclays and nanosilica the relatively low content of hydroxyl groups on their surfaces makes HNTs relatively hydrophobic, although, sometimes, this is not sufficient for guaranty a good interfacial adhesion in composite systems. Further hydrophobic treatment is required to improve HNTs compatibility with polymer matrixes, maximizing interfacial interactions. In the present study, different percentages of EPB (2,2-(1,2-ethene diyldi-4,1-phenylene) bisbenzoxazole) was used to perform anon-covalent functionalization of halloysite, based on electron transfer interactions. The functionalization is characterized by specific surface area (BET), thermogravimetric analysis (TG) and water/toluene extraction experiment.

Mar 1, 2018

By Rongjin Zhu, Yue Wu, Shuxing Qiu, Qingyun Zhang, Shengfu Zhang

Co-pyrolysis of biomass and coal was investigated as an effective way to reduce the greenhouse gas emission. The effects of poplar on the thermal behavior of fat coal were studied using thermogravimetric analyzer. The blended samples heated to characteristic temperature were subjected to attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to characterize the macromolecular structure. The results indicated that the synergistic effects existed in co-pyrolysis process of blends since lower char yield than calculated values, and the synergistic effects presented positive and negative trend with the increase of temperature, respectively. The carbonyl/carboxyl C=O stretching vibration functional groups and aliphatic side chain from individual fuels were decomposed in advance during co-pyrolysis. Furthermore, the hydrocarbon-generating potential (A-factor) and thermal maturity(C-factor) of the mixtures showed nonadditivity performance.

Mar 1, 2018

By Xuemei Zheng, Aiyuan Ma, Guojiang Li, Tingfang Xie, Jinhui Peng, Libo Zhang

A new microwave roasting technology for the removal of Cl from zinc oxide dust is proposed in this paper. The effect of important parameters, such as roasting temperature, holding time and stirring speed, were investigated and the process conditions were optimized using response surface methodology (RSM). The experimental results show that zinc oxide dust dechlorination rate can reach more than 95.66% and meet the requirements of wet smelting electrolysis when controlling the stirring speed of 60 r/min,roasting temperature of 650 °C, holding time of 30 min. In addition, the effect of roasting temperature and holding time on removal ef ficiency of Cl was most signi ficant. As a result, the Cl content was decreased without the risk of pollution. This makes it as a good choice for a more ecological treatment of zinc secondary resources.

Mar 1, 2018

By Leonardo Gonçalves Pedroti, Fernando de Paula Cardoso, Beatryz Cardoso Mendes, Afonso Ramos Garcez de Azevedo

This work aims to produce paints using granite waste, as a pigment, and compare their performance to soil pigments based paints, in terms of hiding power and abrasion resistance. Initially, the residue and soils were physically, mineralogically and morphologically characterized. For the production of the paint samples, an experimental model was defined, based on the variation of the proportions of pigment and resin. The proportion of water varied in each sample, in order to maintain the viscosity within a range considered ideal for application. Sequentially, tests were done to determine the hiding power and abrasion resistance of inks. It was found that, in comparison to soil paints, the granite residue paints presented greater hiding power. This result can be explained by the characteristics of the granite residue, which allowed a high nonvolatile content in the mixtures. With respect to abrasion resistance, granite residue paints showed less resistance than soil paints, possibly due to the granulometry of the residue that resulted in a greater roughness of film. In addition, none ink sample satisfied the minimum specifications prescribed in the Brazilian standards for hiding power and abrasion resistance, at the same time. This means that these inks, when used, will require more repair and repainting over time than conventional paints.

Mar 1, 2018

By Manis Kumar Jha, D. D. Pathak, Archana Kumari

Treatment of secondary/waste to recover rare earth metals (REMs) is gaining importance due to its increasing global demand, lack of availability of high grade natural resources and huge generation of secondaries. Present paper reports the critical review on available processes for recovery of REMs from secondaries viz. manufacturing scraps, e-waste, industrial residues such as red mud, fly ash, waste water, etc. Hydrometallurgical processes with combination of Beneficiation/ Pyro-/Electro techniques are discussed to recover REMs effectively. The recommended processes require less energy to deliver high purity yield which is one step towards green environment. Salient findings on various methods are reported with recommendations which will be helpful to researchers working in the area of REMs extraction.

Mar 1, 2018

By Jose Carlos D'Abreu, Edelink Efrain Tinoco Falero, Mauricio Marcos Otaviano

The production and consumption of Direct Reduced Iron (DRI) are continuously increasing, as a consequence of the impact of shale gas extraction technology on the Natural Gas (NG) market. Considering this context, DRI may improve the Blast Furnace (BF), Electric arc Furnace (EAF) and LD converter ’s productivities and consequently their competitiveness. In this work the results of a cooperative research conducted by PUC-Rio University and a Brazilian mining company are presented. Laboratory-scale simulation tests, using DR commercial pellets and typical industrial operational parameters of a benchmarked DR shaft furnace, were conducted and planned using statistical and factorial analysis. In the simulated experiments, the following three regions of the DR shaft furnace were considered: Reduction Zone (RZ), Transition Zone (TZ) and Cooling Zone (CZ). Three stages were considered in the research development: (i) the reactions and equations concerning pellet metallization and Carbon precipitation were analyzed; (ii) experiments focused on the de finition of the carburization kinetic equations occurring in the Transition and Cooling zones, and finally, (iii) aimed to develop the “METCARB” model, a computational program conceived to simulate mathe- matically the metallization and carbonization reactions along the height of the furnace. In conclusion, a comparison is made with industrial results in order to validate the resulting “METCARB” model.

Mar 1, 2018

By Zhucheng Huang, Zhikai Liang, Ronghai ZHONG, Lingyun Yi

In this work, research of reduction process was studied by means of rotary kiln (u1.5 m /C215 m) process anatomy in order to provide fine guidance to large-scale operation. It was shown that the average reduction degree of 89.96% and metallization ratio of 85.15% were obtained at the highest temperature of 977°C and total residence time of 90 min. The generation amount of metallic iron in section of temperature higher than 900°C and lower than 900°C was 34.15 and 56.38%, respectively. The section of lower temperature of 830–900 °C played an important role in formation of metallic iron, making it possible for mini-pellet to reduce quickly at lower temperature. Two main tasks were completed for mini-pellets in rotary kiln: the reduction of iron oxides in the range of 15.0–4.5 m as well as migration and bene ficiation of metallic iron, facilitating the subsequent separation of iron and gangue minerals.

Mar 1, 2018

By Ahmet Haxhiaj, Bajram Haxhiaj

Based on the placement of lead and its consumption in industry branches, the paper deals with the composition of lead in the massive of Kopaonik. Removal, tenuity and grinding of galenit. The paper in particular treats the flotation process, and also treats physico-chemical bases of reagents in the process, as well as decanting, drying, filtering and storage of concentrates. Verification of the chemical composition of Pb concentrates with Pb, Zn, Bi, As, Sb, In, Au, Ag, etc. It is special that in Kopaonik massive the ratio of Pb: Zn composition is 1.4:1.0 and during the flotation lead is inclined to go with pirotines concentrate more than is allowed. We are strongly focused to maximally decrease the Pb amount that goes with pirotine concentrates and wastes. The paper as such gave the first effects in optimizing of these parameters with positive effects in flotation process in Trepca.

Mar 1, 2018

By Jilai Xue, Shuming Huang, Zengie Wang

The corrosion behaviors of chrome corundum/magnesia in laterite nickel slag were investigated by static crucible method. The results show that the molten slag can penetrate into chrome corundum or magnesia which are used as lining materials in smelter furnace, and the corrosion can occur at the slag-refractory interface and the inner area of the refractories as well. Both the penetrated amount of slag and the penetration depth of Fe, Si increase with increasing FeO content (10–25 wt%) in slag. Such penetration in magnesia is stronger than that in chrome corundum under the same corrosion conditions, as more pores in magnesia may provide channels for slag penetration and corrosion product transportation. A damage of the refractory linings and short service life of smelter furnace may happen during metallurgical processing slag with high FeO content.

Mar 1, 2017

By Pengqi Zhang, Mingcheng Bing, Lixiong Shao, Shuxing Qiu, Qingyun Zhang, Shengfu Zhang

Coal desulfurization has been regarded as an effective pretreatment for clean fuel and less environmental pollution. The microwave irradiation was used to desulfurize the Nantong coal leached with H2O2 and NaOH. The results showed the desulfurization rate of the coal is very low by directly microwave irradiation, while the coal samples leached with H2O2 and NaOH by microwave irradiation could effectively improve the desulfurization rate. The optimum desulfurization conditions were obtained as 10-min irradiation time, 800 W irradiation power, particle size below 74 μm, 1:1 concentration ratio of H2O2:NaOH, in which the desulfurization rate reached 51.14% of the total sulfur content. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra of coals structure before and after treatment have shown the bands in both coals changed slightly except the relative intensity of some absorption ones. It can be found that most of FeS2 and –S–S– functional groups transferred after treatment, while –SH and –S=O– had almost no changing by ATR-FTIR spectra analysis. The structures of coal matrix would not be broken by microwave irradiation in reasonable the reaction conditions.

Mar 1, 2017

By Shusen Cheng, Dongdong Zhou

The high temperature distribution in ironmaking and steelmaking industry is very important to control the smelting process. Although equipment is available to measure the temperature in the smelting process, in general it could just measure one certain point or only at discrete times. The real time temperature distribution in ironmaking and steelmaking is important because it could reflect reaction information and help to control the operation parameters. In this paper, a new method to detect the temperature distribution in ironmaking and steelmaking through the application of digital imaging system based on the color CCD was studied. In addition, the two-color method and partial least square method were used in the calculation model to improve the accuracy. The results agreed well with the measured temperature.

Mar 1, 2017

By Xiao Hong, Zhang Wenqiang, Gao Bing

The characteristics of top charging coke (coke 1) and stamp charging coke (coke2) were investigated. The weight loss ratios of two kinds of cokes with and without alkalis were measured after reacting with CO under the temperature of 2 900, 1000, 1100 and 1200 °C respectively. The microstructures of original cokes were observed by SEM. The experiment results show that, with no addition of alkali, the weight loss ratios of coke 1 and coke 2 were nearly the same under the temperature of 900 and 1000 °C. While the weight loss ratio of coke 2 was much larger than coke 1 under the temperature of 1200 °C. With alkali-rich, the weight loss ratio of the two cokes was almost the same at 1100–1200 °C.

Mar 1, 2017

By M. Firdaus, M. A. H. Shuva, M. A. Rhamdhani, G. A. Brooks, S. Masood, M. A. Reuter

Declining grade of primary ores and resource efficiency have led us to process more alternative metal resources such as e-waste. One of the processing routes for extracting valuable metals from e-waste is through the black copper smelting. However, the underlying knowledge of the thermodynamics behaviour of the valuable metals contained in e-waste during smelting are limited which prevent us from developing an optimised process to recover all the metals. These different metals clearly will have different favourable conditions for their extraction. To illustrate this, the distribution behaviour of germanium (Ge) and palladium (Pd) between liquid copper and ferrous-calcium-silicate slag during black copper smelting was analysed. It was demonstrated that oxygen partial pressure and slag composition affect the partitioning of these metals to the copper phase and the favourable slag chemistry for recovering these metals is opposing. Considering the available thermodynamic data of these metals, an analysis for the optimum conditions is presented.

Mar 1, 2017

By T. Thuy Minh Nguyen, Sathish K. Lageshetty, Paul Bernazzani

The addition of nanoparticles to epoxy resins often results in changes in the physical properties of the material particularly when dealing with thin coatings. By characterizing the mechanism of interactions between nanoparticles and polymer chains the material could be tailored for specific applications or properties such as enhanced biodegradability. This study compared the characteristics of common DGEBA resin coated on a silicon substrate and embedded with nanoparticles of TiO2 and Fe2O3. Specifically, we investigated the rate of curing, and the thermal stability of these nanocomposites. Results show changes in the stability for compounds containing TiO2, while Fe2O3 significantly enhanced the curing rates of the nanocomposites while maintaining similar physical properties.

Mar 1, 2017

By Jianzhong Li, Yunkai Wang

Lead substrate anodes are widely used in the electroplating and electrolytic field. However, with the change of internal stress, the oxide films are gradually generated on the surface of lead anode. Their structure and stress properties were studied during the oxidation by means of Raman spectra, XRD, SEM. The result showed that the diffraction peaks of lead were mainly found at the initial oxidation stage. With increasing oxidation time, Pb diffraction peaks were weakened and the diffraction peaks of PbO/PbO2 strengthened remarkably. When the oxidation time was above 10 min, monoclinic PbCrO4 was also generated in the oxide film with CrO4 2 ions solution as electrolyte. Raman spectra revealed that Raman peaks of PbO/PbO2 were gained. In addition, Raman peaks of PbCrO4 at 830–840 cm−1 were found using the CrO4 2 ions as electrolyte. Based on the relationship of the internal stress of oxide film and Raman peaks shift, PbO/PbO2 induced obvious stress generation in CrO4 2 ion electrolyte. The nucleation style of oxidation film was 3D progressive nucleation at first. After the peak current, it turned to be 3D instantaneous nucleation. In the oxidation process, the internal stress of PbO/PbO2.

Mar 1, 2017