Proceedings of 1st International Conference on Mineral Engineering and Material Science (iCMEMS2017), 20-22 November, Sydney, Australia 2017

ISBN: 978-0-6480147-7-5

Abstract: This paper will Waste materials, such as fly ash and bottom ash, are being produced in increasingly high volumes owing to the dependence of numerous industries on coal-derived electricity. While a small fraction of these materials are used in the construction industry, the large majority is sent to landfill and ponds. Work at UNSW in collaboration with Vecor (Australia) Pty. Ltd. on waste material utilisation has resulted in the development of processing procedures and in situ composite materials consisting of percolated and direct-bonded single-crystal mullite fibres. Despite starting with a vitreous material, the products perform as pure mullite, exhibiting outstanding long-term thermal and mechanical stabilities at temperatures >1600°C. The processing, characterisation, analyses, and performance of these materials will be discussed.

Abstract: This presentation will cover two recent nano approaches (viz., Graphene Coating and Nanocrystalline Alloy Structure) for mitigation of corrosion/oxidation of metals and alloys.
A monolayer or a few atomic layer thick graphene coatings on metals have been shown to improve their corrosion resistance by up to two orders of magnitude. However, there are considerable variability in the literature on the degree of improvement (for example, improvement in aqueous corrosion resistance of copper due to graphene coating is reported to vary from insignificant to two orders of magnitude). While resons for this variability will be discussed, this presentation will also discuss the challenges in the possible application of such disruptive approach to corrosion resistance of most common engineering alloys, i.e., steels.
Author hypothesised that a nanocrystalline structure can impart extraordinary oxidation resistance, and subeseuqnetly validated this hypothesis. A thorough experiematl work established that a Fe-Cr nanocrystalline alloy with only 10wt% Cr can provide as much oxidation resistance as a Fe-20Cr alloy, suggesting possibility of Fe-Cr alloys with the necessary oxidation/corrosion resistance at much lower Cr contents. A thorough surface/subsurface characterization of oxidized alloys, using secondary ion mass spectrometry has provided a sound mechanistic understanding of the remarkable improvement in oxidation as result of nanocrystalline structure.

Abstract: Batteries are everywhere in our modern society and their consumption is ever on the increase. They can be either primary (disposable) or secondary (rechargeable) batteries. Regardless, the majority of batteries are disposed of to landfills at the end of their useful lives with less than 5% of them being recycled. This represents a significant loss of valuable, non-renewable resources, in addition to the potential to cause serious environmental damages from leakage of chemicals in the electrolyte and leaching of heavy metals. The material loss is even more substantial for the rechargeable batteries as they contain large amount of transition metals in the cathode such as cobalt (Co), nickel (Ni) and manganese (Mn).
Research efforts to recover these valuable materials have surged in recent years from the increased demand on rechargeable batteries and the associated increase on the spent batteries when they reached their useful lives. Many process flow charts have been reported in the literature, which are largely based on the pyrometallurgical or hydrometallurgical extraction methods, or their combinations, of the constituent metals.
In this presentation, I will first provide an overview of the spent batteries in the world with some statistics on Australia, China, Europe and the United States. I will then discuss some technical specifics of several representative processes that are reported in the literature, with a focus on the materials recovery from spent lithium ion batteries. I will conclude my presentation by offering my personal views on the key issues that must be addressed to improve the commercial viability of the battery recycling processes and ultimately the sustainability of the battery industry.

Abstract: In China, the first heap bioleaching plant with annual capacity of 10,000 tons cathode copper was established by Zijinshan copper mine in December 2005. With a long time production of closed cycle, problems like excess acid, iron accumulation and water balance were occurred due to the special characteristics of ore, geographical environment and climate. It was found that the excess dissolution of pyrite was an important factor leading to low productive efficiency. Aiming at this problem, a selective-bioleaching test with 10,000 tons ore was conducted and an annual output of 30,000 tons of cathode copper heap bioleaching-solvent extraction-electrowinning plant was re-established in 2012. During the test, ore particle size was crushed to -40 mm. By using engineering technologies, such as spraying and leisure regulation, free acid neutralization and raffinate COD concentration control, the oxygen concentration of the inside heap was controlled in a lower level, and solution pH, heap temperature and ORP was regulated with 1.5~1.7, ~40 °C and <760 mV (vs. SHE). Therefore, jarosite was self-generated in the heap, and reduced the content of iron in the solution, and sulfur oxidizer dominated microbial community was thus formed. After a leaching period of 227 days, copper leaching rate was reached 82.4%, and iron leaching rate was controlled at 6.2%. The results showed that the selective-bioleaching of Cu from low grade copper ore was succussed. During the application of the new technology in the past five years, a total of 79266.16 tons cathode copper was produced from low grade ore of less than 0.3 % with the production cost of less than 22,000¥/t•Cu. The industrial applications of green circulation and biological extraction of copper from low grade copper ore was achieved.

Abstract: Leaching of gold by cyanide has brought great harm to the environment and staff due to highly toxic. This research introduces a leaching approach to extract gold from gold ores with high sulfur and arsenic contents using a new non-cyanide leaching agent(HJ-1). The properties of ore, mechanism and process of leaching were studied. The results confirm that the gold was mainly oxidized into trivalent and complexed with SCN- as Au(SCN)4- in HJ-1 leaching system. And it is shown through the research of process mineralogy that there were 2.7% of As and 9.206% of S closely associated with gold. Although the grade of gold was highly 98.34g/t, it also was deemed to refractory gold ore. By compared the leaching conditions and pretreatment methods, high temperature roasting-acid leaching has been adopted. After roasted at 750℃ for 2 hours and grinded for 6 min, the gold leaching rate can reach as high as 94.09% after 3h leaching under the optimized condition of initial pH 2.0, concentration of leaching agent 0.8mol/L, concentration of oxidant 0.05mol/L, and leaching temperature 298 K.

Abstract: In mineral processing, the particle size reduction process using mills is a highly energy intensive process. Due to the complex of slurry flow in mills, there are no design rules or correlations that can be used to quantitatively predict the performance of a specific mill process. Computational fluid dynamics (CFD) modelling, due to large increases in computing performance, improved software and multiphase algorithms, allow prediction of complex flows such as those encountered in grinding process, which previously could not have been achieved.
This paper aims to apply a multi-scale modelling method to study the complex motion of slurry in mills. The discrete particle method (DPM) will be used to laboratory mills. Following model validation, the information from the DPM model will be used to improve the constitutive correlations of a process scale modelling, e.g. the two fluid modelling (TFM). The TFM will be then used for an industrial scale mill simulation and provide useful information to support industrial scale mill design/controls.

Abstract: Synthesis of stable and luminescent core-shell structure of nanocrystalline silicon and silicon oxide has been a challenging problem. Our attempt to fabricate stable nanoparticles of Si/SiO2 core/shell structures has revealed that fabrication route has significant impact on the structure of the nanocrystals (NCs) and hence on the properties of the synthesized systems. So far we have successfully synthesized stable and luminescent core-shell nanostructures of Si NCs and Si oxide having spherical and rod like structures (Fig. 1) via inexpensive techniques of mechanical milling and exfoliation of porous Si. The colloids of Si NCs exhibit intense room temperature PL, detectable with the unaided eye. The PL spectra of the colloidal Si NCs are characterized by appearance of double peaks and excitation dependent shift of emission peaks which is explained in terms of dominant transitions between quantum confinement induced widened band states and oxide related interface states. The emitting states of porous Si layers, however, are different and the peak is red shifted by ~1 eV compared to that of the colloids. This is explained in terms of discretization of phonon density of states during formation of individual nanorods. Dry and wet etching of the core-shell nanostructures in CF4 plasma and aqueous HF respectively, resulted in partial removal of the oxide shell and formation of free standing spherical quantum dots of Si with dimensions ~2 nm (Fig. 2). Luminescent characteristics of the etched samples confirm the proposed mechanism of radiative transitions involving phonon bottleneck. Such core-shell nanostructures of Si and free-standing quantum dots represent important building blocks in nanoscale science and technology and have immense potential applications.

Abstract: Here we shall discuss mainly the replacement of TIO2 active layer of dye sensitized solar cell (DSSC) with graphene conducting polymer hybrid. Both graphene oxide and graphene quantum dots are used for this purpose. The replacement of TiO2 layer of the traditional DSSC is made by a newly synthesized semiconducting poly[3-(2-hydroxyethyl)-2,5-thienylene] grafted reduced graphene oxide (PHET-g-rGO) affording a reasonable PCE [1]. The TEM study indicates that in PHET-g-rGO the fibrous network morphology of PHET remains appended on the graphene surface making it a good electron transport promoter. The diffuse reflectance spectra correspond to a decrease of band gap from 1.86 eV in PHET to 1.38 eV in PHET-g-rGO. The photoluminescence (PL) intensity for pure PHET gets quenched and the emission peak gets red shifted by 13 nm due to grafting with rGO suggesting an efficient electron-hole pair separation. By first time replacing the TiO2 in traditional DSSC with PHET-g-rGO the cell characteristics are as follows: the open circuit voltage equal to 0.61V, photocurrent density = 7.5 mA/cm2 and the fill factor (FF) = 0.668 giving an overall power conversion efficiency(PCE) = 3.06 %. In order to improve the PCE further, aniline is in-situ polymerized in aqueous dispersions of graphene quantum dots GQDs to produce different polyaniline PANI-GQD (PAGD) hybrids. We have synthesized (GQDs) by a facile Sono-Fenton method and PAGD hybrids are produced without using any external dopant.[2] The fluorescence intensity of GQDs drastically quenches in the PAGD hybrids suggesting effective charge transfer between the GQDs and PANI chains. In PAGD composites the dc- conductivity increases by three orders from that of GQDs and the current-voltage (I-V) characteristics of PAGD composites indicate that on irradiation with light almost a reversible photoresponse occurs. DSSCs fabricated with PAGD hybrids and N719 dye indicate highest PCE of 3.12%. Impedance data of the PAGD hybrids exhibit semicircular The impedance spectra of the DSSCs indicate the presence of three semicircles exhibiting a complex equivalent circuit comprising of three R-C circuits and analysis of the data yield the life time values of photo-injected electrons supporting the PCE variation of PAGD hybrids. Trihybrid (GPPS) hydrogels constructed by 5,5'-(1,3,5,7-tetraoxopyrrolo[3,4-f]isoindole-2,6-diyl) diisophthalic acid (P), graphene oxide(GO) and PEDOT:PSS, are used for active layer of DSSCs[3]. DSSCs are fabricated taking the GPPS gels as active materials and PCE increases with increase of PEDOT:PSS concentration showing a maximum PCE of 4.5%. IPCE curve shows absorption range 360-700 nm with maximum absorbance of ∼57%. The properties of methyl ammonium lead iodide(MAPbI3) perovskite solar cell with poly(3-thiophence acetic acid)(P3TAA) as hole transporting material(HTM) and dense layer of ZnO nanoparticles film as electron transporting material(ETM) is described using the conventional ZnO(n)/Perovskite(i)/P3TAA(p) (n-i-p) architecture[4]. The current density(J)–voltage(V) curves on illumination with light of 100 mW/cm2 indicate the average PCE to be 7.38±0.59% at ambient condition. The UV-Vis and impedance spectral results clearly explain the above results, signifying the influence of interface on the performance of hybrid solar cells.

Abstract: Thorium is an important radioactive element associated with rare earth elements in the resource such as bastnaesite and monazite. It is also a potential nuclear fuel due to the conversion of 232Th to 233U under slow neutron bouncing. So, to eliminate the radioactive pollution and provide the feed for the novel nuclear reactors, the recovery and purification of thorium is an important topic of rare earth metallurgy. From the 1970’s, our lab has been working on the separation and purification of thorium from the rare earths ores using primary amine as the extractant. Recently, we developed a series of nitrogen-containing extractants to recover thorium from rare earth concentrate and screened out an efficient one Cextrant 230 which has applied for invention patents PCT/CN2015/077208 and PCT/CN2015/077212. The novel extractant exhibits excellent extraction performance toward thorium in sulphate medium at lower acidity. Under the same conditions, trivalent rare earth elements are hardly been extracted. The separation of cerium(IV) and thorium can be realized by adjusting the aqueous acidity. A bench-scale test to deal with sulfuric acid leaching of bastnaesite was processed, by which thorium was efficiently recovered. To further purify the obtained thorium product, another extractant labeled N501 was screened. A solvent extraction process with centrifugal extractors was proposed to prepare ultrapure thorium, which has been patented as China patent ZL201110074345.8 and ZL201210552752.X, US patent 9,347,116 B2 and Australia patent 2013201027. Dozens of kilograms of ultrapure thorium products was obtained.

Abstract: In this paper a new tailings dam stability monitoring method is proposed based on guided wave inspection technique. Crushed stone aggregates with different volume were firstly buried in a drilled hole located in a tailings dam experimental model and a round steel rod was placed in the centre of crushed stone aggregates. Then tailings dam failure experiments were conducted. During the dam break process, tailings deformed and guided waves were excited by collision and friction between the rod and aggregates. Based on that, guided wave event rate, energy rate and energy fractal dimension versus time relationships were obtained. Results show that guided wave event rate and energy rate increase sharply and reach the maximum on the verge of tailings dam break, while guided wave energy fractal dimension increases at first and then decreases sharply before tailings dam break. So the change trend of guided wave event rate, energy rate and energy fractal dimension can be treated as precursor characteristics of tailings dam break and guided wave parameters as new indicators can be used in tailings dam stability monitoring.

Abstract: In this paper, Eh-pH and speciation diagrams are constructed for gold leaching in the Co-NH3-S2O32-- H2O system from thermodynamic calculations. The diagrams show that thermodynamically stable redox couples of Co(NH3)63+/Co(NH3)x2+ (x = 1-6) can be formed and drive the dissolution of gold in ammoniacal thiosulfate solutions. Based on the diagrams, a possible mechanism for the Co(III)/Co(II) electrochemical-catalytic leaching of gold with ammoniacal thiosulfate is proposed. The calculation also reveals the differences in the oxidization potential and structural stability of the Co(NH3)63+ and Cu(NH3)42+, which explains the much reduced thiosulfate consumption in the Co-NH3-S2O32--H2O system compared to that in the Cu-NH3-S2O32--H2O system. Results presented in this paper offer a theoretical basis for the optimization of the cobalt-catalyzed thiosulfate leaching of gold.

Abstract: The strength and behaviour of coke at high temperatures has a huge impact on its performance in the ironmaking process. Prior studies reporting the effect of temperature on the failure stresses of cokes have not always shown consistent trends owing to differences in sample sizes, properties, and testing methods. In the present work, a high-CSR Australian coke was subjected to high-temperature mechanical tests using a unique high-temperature test facility at ANSTO to determine its compression strengths and the associated microstructural and mineralogical modifications. X-ray diffraction analysis and micro-CT analysis were used to determine the mineralogical and microstructural changes in the cokes after testing. The work showed that there were three regimes of deformation in the coke with increasing temperature. Furthermore, the work showed that compression strengths of the coke were higher at elevated temperatures in comparison to the observed values at room temperature. Microstructural analysis showed an increase in the extent of porosity after high-temperature testing owing to the in situ reduction of ash species in the coke. With increase in temperature, it is expected that glassy phases formed by ash fusion as well as increased graphitisation assist in enhancing plastic flow, which contributes to an increase in strength of the coke samples at these temperatures. However, with increasing graphitisation extents, the load-bearing capacity would decrease, leading to a lowering of the maximal strengths at the top temperatures. The findings provide an improved understanding of the mechanisms affecting high-temperature strength development in cokes and can further assist in correlations the strengths with variations in coke and parent coal characteristics.

Abstract: Pyrolysis of coals to produce cokes is an important part of the ironmaking process. Coal pyrolysis to coke is an energy-intensive process and involves the transformation of the coal from a soft carbonaceous material to a hard coking structure. During this process, volatiles present in the coke are released and coal tar is extracted, and this has numerous applications as a source of various chemicals for different industries as well as carbon for anodes. This work investigates the effect of blending different amounts and proportions of waste polymers with coals in order to enhance the coal tar yield and to modify the chemical product characteristics. Coal and polymer blends were pyrolysed at 500°C and the tar and volatile compounds were collected by condensation. The collected tars (solid and liquid) were characterised using gas chromatography-mass spectrometry (GC-MS) to determine the major components. Further analysis of the proportions of the major organic components was conducted using solution NMR analysis. When blended with the polymers, all the coals showed a proportional increase in their tar yields. The highest yields were observed with the addition of polystyrene (PS), followed by rubber tyres (RT), while polymers with aliphatic chains produced lower yields. This work has shown potential for enhancing the coal tar yield and for modifying coal tar properties through polymer addition, which can add further value by providing additional uses for pyrolysis products and by removing waste polymers from the disposal stream.

Abstract: The type, concentration, and distribution of dopants in TiO2 thin films have a huge impact on their photocatalytic performance. In the present work, spin coating followed by annealing at 450°C for 2 h in air, was utilised to fabricate TiO2 thin films codoped with V and Co (0.02-2.00 mol% total codopant concentration) on fused silica substrates. Two unique codoped TiO2 thin films with varying through-thickness dopant concentration were fabricated in addition to the samples with a conventional constant concentration throughout the film. One film had a descending concentration (DC) of codopants from the film surface to the substrate-film interface, while the other had an ascending concentration (AC) of codopants from the film surface to the substrate-film interface. GAXRD and Raman analysis confirmed that all fabricated films were composed of anatase and the data suggested that that the dopants were incorporated into the lattice. AFM analysis showed that the grains were small and uniform for all the films and did not change with the codopant concentration. At higher codopant concentrations, surface amorphisation and liquid formation occurred which led to a reduction in surface roughness and crystallinity; in addition, pores were also formed on the surface. SIMS analysis confirmed the varying distribution levels in the AC and DC films and the constant levels in the other films. XPS analysis identified the presence of Co2+, Co3+, V3+, V4+, and possibly V5+ suggesting the presence of intervalence charge transfer. UV-Vis analysis showed that the films were highly transparent (~80%) in visible light with similar band gap values. Assessment of photocatalytic performance in terms of methylene blue degradation showed that the DC sample outperformed the AC sample due to its greater roughness, larger grain size, higher crystallinity and smaller band gap.

Abstract: Fly ash (FA) is a ‘waste’ by-product produced in large amounts in coal thermal power stations to generate energy. Fly Ash consists of a wide range of rigid ceramic oxides as well some unburnt carbon. Fly ash properties are equal or better than the properties of other filler materials. FA is useful as a filler to improve mechanical properties of polymers, reduce the cost of product and to get lightweight composites.
Work was undertaken to try the possibility of reducing the particle size and increasing the particle surface area of the Australian Fly Ash by using conventional ball milling. Increasing the particle surface area is very important; which gives better adhesion to other materials in order to make composites.
As a result, a 10 hrs ball milling was done to reduce the particle size by approximately 50%. Using ball milling compared to as received raw fly ash generated a 4-times surface area. X-Ray Diffraction peaks of the ball-milled Fly Ash showed evidence of some line broadening, possibly due to residual stress caused by the grinding process. SEM shows irregular shaped of ball milled Fly Ash particles and also found reduction in size.

Abstract: It has been shown that breakage rate follows the first order kinetic only for a short time at the beginning of grinding process. Thus, most of the available discrete element models (DEM) to model the grinding process are adversely affected as they rely on accurate determination of breakage rate value for their calculations. To present a solution, current study aimed to develop a DEM model which directly applies the particle breakage into the simulation. At each impact event if particle is considered to be broken, the determined fragments are replaced with original particle, as very similar to real grinding environment. To validate the developed model, a grinding ball impacting an unconfined particle bed was simulated at different impaction energy. Energy distribution, breakage rate and particle size evolution were examined. It was shown that fines accumulation led to deceleration in top size breakage rate. The deviation of breakage rate from the first order kinetic was highly effected by impaction energy. A model representing the time dependent breakage model was tested to take into account the impaction energy role. The results proved that there is a need for DEM models which can simulate the grinding process similar to its real environment, with adequate accuracy and independent from the variation of breakage rate.

Abstract: This paper studies rheological properties of elongated ellipsoidal particles in a model annular shear cell in stress controlled flow condition using the discrete element method (DEM). Particle orientation and volume fraction of the flow are considered. Probability distribution of particle orientation angle exhibits the effect of different shear rates as such that at lower shear rates there is a systematic increase in number particles aligned to the direction of flow with the increase of load, which is not found in the study of higher shear rates. Then, a correlation between orientation angle and volume fraction for different shear rates is observed. It shows that, for the particle assembly volume fraction above 0.55, there is a noticeable influence of shear rate on the relationship between orientation angle and volume fraction. For volume fraction below 0.55, the relationship curve collapse into a single curve indicating that the relationship is no longer affected by variation of shear rate. This observation has a similar pattern with the correlation between kinetically scaled stress and volume fraction, which has been used to determine the transition between kinetic and intermediate regime for spherical particles.

Abstract: Traditional gas cyclones are effective in collecting fine but not ultrafine particles. A recent proposed technology, cloud-air-purifying (CAP) shows that by introducing moisture in the cyclone, the collection efficiency for ultrafine particles can be significantly enhanced. This paper presents a numerical study to understand the effect of moisture content on the collection efficiency of fine to ultrafine particles in a gas cyclone. The multiphase (air, vapour and particles) flow in the cyclone is simulated by computational fluid dynamics (CFD) by using Fluent software. The turbulence of air flow is modelled by the Reynolds Stress Model (RSM), and the particles are modelled by Lagrangian particle tracking (LPT) model. In addition, the particle growth due to the absorption of the moisture is modelled and implemented in Fluent simulations through the user defined function (UDF). The effect of moisture content on the performance of the cyclone is studied by a series of controlled numerical experiments. The results demonstrate that the particle collection efficiency increases with the increase of super-saturation rate. Ultrafine particles can be more effectively collected because of the increase in their sizes. Moreover, three different flow patterns of particles are identified in the cyclone, which can be related to the micromechanisms of the separations of different sized particles. These studies can help improve the understanding of CAP technology.

Abstract: As selective laser melted (SLMed) Ti-6Al-4V is a promising structural material for complex shape parts in medical and aerospace engineering, it is necessary to improve its performance to fit higher industrial requirement. Furthermore, microstructure, which can be tailored by altering processing parameters, will dominate material properties. Hence, in order to improve the material properties to meet some specific requirements of applications such as higher ductility or better resistance to crack growth, the relationship of microstructures and properties is worth studying. Among different scanning strategies in SLM, bi-directional scanning strategy has been commonly applied to reduce material anisotropy. As a consequence, a featured microstructure “chessboard” occurs in the cross-section perpendicular to the building direction. This pattern contains two types of microstructures of different components: martensite α’ and α + β phases. The microstructure materials and the geometry of the “chessboard” pattern determines the mechanical properties of the SLMed Ti64 at macroscopic scale. In this work, the influence of the “chessboard” microstructure on the mechanical properties of the SLMed Ti64 was investigated. A representative volume element (RVE) was established from the “chessboard” pattern. The finite element method was applied to predict the averaged Young’s modulus and yield strength of the RVE. A parametric study was conducted to understand the key parameters which form the RVE on the mechanical properties of the SLMed Ti64 at macroscopic scale.

Abstract: Over the years, most of the mineral resources with higher value have already been developed. Therefore, mineral resources with lower value and a higher level of impurities will need to be developed to cater to the increasing global resource demand. In an Australian context, mineral processing dependency on offshore facilities has been dominant compared to the onshore processing facilities, particularly to reduce the higher development costs. In addition, impending restrictions on the constituents such as penalty elements during transportation of mineral concentrates will lead to restrict the offshore processing flexibility. Innovation of low cost development methods to produce high value mineral concentrates will be vital. Amount of impurities could substantially impede the marketability of any mineral concentrate. Therefore, upgrading of mineral concentrates in onshore facilities will become vital for the Australian developers to eliminate penalty elements associated with high value concentrates.
This study will review the economic context of Australian copper resources with penalty elements. More prominence is given to the processing facilities with the potential to remove a host of impurity elements at a lower energy dependency. Overall, this study contributes to the understanding of mineral resources and the emerging challenges for better decision making and planning in the mining processing industry.

Abstract: The interphase region of nanoparticle-polymer nanocomposites plays an important role in their property enhancement. In this paper, the interphase characteristics including interaction strength and effective thicknesses of epoxy nanocomposites with either defective or functionalized CNTs are determined using molecular dynamics (MD) simulation. CNTs with monovacancy and trivacancy are created by removing one- and three-bonded carbon atoms from a pristine CNT, respectively. In addition, amine was chosen as the functional group being end-grafted to the sidewall of CNTs. The different concentration of amine was applied to identify the best functionalization for reinforcing the CNT-epoxy nanocomposites. The atomic density profiles of epoxy atoms were determined to characterize the density gradient along the radial direction from CNT long axis in the interphase region and quantify the effective interphase thicknesses. The calculated interaction energies between CNTs and epoxy matrix confirm that the strong adhesion strength exists between CNT and polymer matrix and the values of predicted interphase thickness are reasonable compared to those in literatures.

Abstract: Carbon dioxide (CO2) is the major greenhouse gases exhausted from the combustion of fossil fuels (coal, oil and natural gas). CO2 capture, separation and sequestration technology is increasingly critical to reduce CO2 emissions. In present study, Monte Carlo and Molecular Dynamics simulations have been used to examine CO2 adsorption in fluoridised and non-fluoridised HKSUT-1. Fluoridised HKUST-1 shows a remarkable CO2 performance at low pressure. Radial Distribution Function and Mean Square Displacement analysis have been employed to explore the adsorption site of CO2 and it binding strength within MOFs that CO2 molecules in HKSUT-1 are more likely to diffuse into the Cu metal sites. However, the adsorbed CO2 in HKUST-1F are bound closely to fluoride atoms, reducing their mobility.

Abstract: In this paper, a kind of special composite structure powder produced by grinding apatite minerals and titanium dioxide in water medium was studied as a sanitary ceramic opacifier. According to scanning electron microscope (SEM) and Infrared Spectroscopy (IR) test, titanium dioxide evenly distributed on the surface of apatite minerals in the composite powder, and it revealed that these two kinds of particles are connected by not only strong static attraction but also chemical bonding. The powder can be used to replace the equal proportion of zirconium silicate in the production of sanitary ceramic products, and it was found that the appearance of ceramic products was wonderful smooth and pretty white, and some samples’ whiteness value was beyond 90, and the most B values of CIE were less than 3.0. The X ray diffraction (XRD) test results of enamel showed that the glaze materials added in the composite particles can separate out sphene crystal(CaTiSiO5) after ceramic firing, and scanning electron microscope results (SEM) showed that the particles’ size of the precipitated crystals mainly between 0.3~0.5μm, and the particles have uniform shape and uniform distribution. The experimental results show that the optimum mass percentage of the composite particles is 35%, and TiO2 is about 65%, and the best proportion of the composite particles in the glaze materials is between 8.5%~12.0%. These composite particles used as opacifier can achieve a good opaque performance, and more importantly, it can replace zirconium silicate which always introducing radioactive elements in ceramic products.

Abstract: In this paper, a kind of special composite structure powder produced by grinding apatite minerals and titanium dioxide in water medium was studied as a sanitary ceramic opacifier. According to scanning electron microscope (SEM) and Infrared Spectroscopy (IR) test, titanium dioxide evenly distributed on the surface of apatite minerals in the composite powder, and it revealed that these two kinds of particles are connected by not only strong static attraction but also chemical bonding. The powder can be used to replace the equal proportion of zirconium silicate in the production of sanitary ceramic products, and it was found that the appearance of ceramic products was wonderful smooth and pretty white, and some samples’ whiteness value was beyond 90, and the most B values of CIE were less than 3.0. The X ray diffraction (XRD) test results of enamel showed that the glaze materials added in the composite particles can separate out sphene crystal(CaTiSiO5) after ceramic firing, and scanning electron microscope results (SEM) showed that the particles’ size of the precipitated crystals mainly between 0.3~0.5μm, and the particles have uniform shape and uniform distribution. The experimental results show that the optimum mass percentage of the composite particles is 35%, and TiO2 is about 65%, and the best proportion of the composite particles in the glaze materials is between 8.5%~12.0%. These composite particles used as opacifier can achieve a good opaque performance, and more importantly, it can replace zirconium silicate which always introducing radioactive elements in ceramic products.

Abstract: Graphene oxide(GO) is an efficient two-dimensional (2D) adsorbent for remediation of trace rare earth ions wastewater, however its major disadvantage of layer stacking in adsorption process has greatly restricted bringing into full play its inherent adsorption ability. Hence we propose the introduction of one-dimensional(1D) carbon nanotubes (CNTs) into 2D GO hydrosol sealed in dialysis bags to form CNTs@GO hybrid hydrosol by ultrasonication for adsorptive removal of rare earth ions. In this work, the effects of pH value, contact time and temperature on Gd(III) adsorption of CNTs@GO hybrid hydrosol were also systematically investigated. The results show that the theoretical maximum adsorption capacity of CNTs@GO hybrid hydrosol with the weight ratio of CNT: GO=1:6 for Gd(III) was observed to soar from 286.86 mg g-1of GO to 534.76 mg g-1 (pH=5.9, t=60min, T=303K), giving a sufficient evidence that the layer stacking of GO nanosheets in the adsorptive process of Gd(III) could be reduced to a large extent with the introduction of CNTs and presenting the remarkable synergistic enhancement effect. The kinetics and thermodynamics analysis reveals that the adsorption of Gd(III) on CNTs@GO hybrid hydrosol was in agreement with the Pseudo-second-order model and Langmuir isotherm adsorption models. CNTs@GO hybrid hydrosol for Gd(III) removal can achieve adsorption equilibrium within 60 min, and can also maintain the adsorption capacity of 347.84mg g-1 after four adsorption-desorption cycles and the desorption rate of 80.03 % at the 5th cycle. In prospect, CNTs@GO hybrid hydrosol sealed in dialysis bags offers great promise for treatment of wastewater containing trace other rare earth or heavy metal ions with dramatically enhanced absorption performance and no second pollution.

Abstract: The flotation separation of muscovite from quartz was investigated using mixed sodium oleate/dodecylamine (NaOL/DDA) collectors. The flotation experiments were conducted on single minerals and their collecting performances were studied by means of adsorption amounts and molecular dynamics simulation. Flotation results show that muscovite presents good floatability while quartz exhibits poor floatability in alkaline condition. Adsorption amounts show that both NaOL and DDA can absorb onto surfaces of muscovite and quartz in presence of mixed surfactants. Molecular dynamics simulation indicates that DDA plays an important role in the adsorption of mixed surfactants on these two mineral surfaces. The molecules of mixed NaOL/DDA are arranged in a rigid and well-ordered packing on muscovite (001) surface. Only a few DDA adsorb on quartz directly, and rest DDA and NaOL molecule exist near by the quartz surface, forming a hydrophilic cylinder-like structure. This study may provide guidance for the flotation mechanism and application of mixed anionic/cationic collectors.

Abstract: The heat consumption per kilogram coal during carbonization process defines the cost of under firing. The consumption is influenced on the one hand, by the oven design and method of operation and on the other hand, by the thermal characteristics of coking coal charged. In order to make in-depth fundamental studies of the actual amount of heat required for the conversion of coal into coke, adiabatic calorimeter and TG-DSC was used for determining the heat of carbonization of a number of coking coals. Heat of carbonization value of 16 coals and coal blends ranging in volatile matter from 17.6 to 34.7% was found in the range of 247 to 406 kcal/kg of dry coal and activation energy in range from 151.6 to 304.2 kJ/mol. It seems that heat of carbonization is an additive property of coal and most coking coal appears to be exothermic reaction during carbonization process. The oxygen contents of coking coals seem to influence the activation energy of coals and heat of carbonization during carbonization process. Heat consumption and H/C found to have negative relationship for both hard and soft coking coal.

Abstract: Careful and promising approaches with regard to the solution-processed nanocomposition based on organic and inorganic materials have been intensively investigated to realize next-generation nanoelectronics which require superb electrical and electronic performance, compared to the conventional materials. Recently, we observed that conducting nanoparticles incorporated into the random networks of carbon nanotubes (CNT) exhibited improved strain/pressure sensing performance on flexible/stretchable substrates. In this presentation, we discuss the material synthesis of solution-processed organic/inorganic nanocomposites and the improved sensing mechanism for highly sensitive and robust human-interactive sensors. By optimizing the material composition and deposition process for solution-processed organic/inorganic nanocomposites, a rapid and accurate sensing performance can be achieved on flexible/stretchable substrates which can be directly attached to the human body without a buffer layer.

Abstract: The thermoacidophilic archaeon Metallosphaera cuprina was isolated from a sulfuric hot spring. M. cuprina is able to oxidize elemental sulfur, tetrathionate (S4O62+) pyrite, and a range of low-grade ores, thus is attractive to biomining industry. Dissimilatory sulfur metabolism with a sulfur oxygenase reductase (SOR) system has been reported for members of Sulfolobus and Acidianus. But SOR system was not identified in the genome of M. cuprina. Recently, we have explored the sulfur metabolism of M. cuprina with genomic, proteomic, and biochemical tools. A hypothetical model of sulfur metabolism in M. cuprina was proposed on proteomic and genomic data, and proteins that involved in sulfur metabolism have been identified in our following studies. Specifically, DsrE/TusA homologs were biochemically characterized, and a novel thiosulfate transfer reaction was found during sulfur oxidation with M. cuprina. More recently, we cloned and identified a CoA-dependent NAD(P)H sulfur oxidoreductase from M. cuprina. The study will cover new understandings of the sulfur metabolism with M. cuprina.

Abstract: The separation of chalcopyrite and talc by froth flotation is a challenge to the whole mineral processing industry as talc is naturally hydrophobic and easily reports to flotation concentrates. To solve this problem, the role of locust bean gum in the flotation separation of chalcopyrite and talc has been studied and its depression mechanism to talc has been discussed. The single mineral flotation results show that both chalcopyrite and talc are floatable in the tested pH range from 3 to 11 and locust bean gum can depress the flotation of both chalcopyrite and talc. However, locust bean gum has stronger depression effect on talc at the pH range of 5-9 with a dosage of 100mg/L. The flotation test on mixed minerals indicates that the use of locust bean gum as depressant can achieve the flotation separation of chalcopyrite from talc and a concentrate with Cu grade of 30.10%, and Cu recovery of 88.06% was achieved when the Cu grade of feed is 15.15%. The reason is that the adsorption amount of locust bean gum on talc surface is larger than that on chalcopyrite surface. Zeta potential and XPS measurements showed that the locust bean gum adsorbed on talc surface mainly through hydrophobic interaction.

Abstract: Aiming at the shortcomings of the impactor wet precipitator, the effective wet dust collector is developed whose unique double W channel structure can increase the dust gas turbulent in the W channel and generate more vortices, which greatly increase the chance of contact between gas and water after the dust gas hit the water. Based on multiphase flow numerical simulation technology, the efficient wet dust collector inlet fluid characteristics of different flow rates were analyzed by FLUENT software, the simulation results show that the faster the dust gas flow rate, the more the eddy current in enclosure and W channel, and those eddy currents increased the time that dusty gases stay in the precipitator in a certain extent. when the velocity is over the certain extent, the dust will be spinning in the vortex and going against the contact between dusty gas and water, which will reduce the dust removal efficiency. From the results, the inlet wind speed of precipitator should be to controlled in 13.6 m/s to 14.5 m/s to make sure the dust removal efficiency is the best, which provide the reference value for the treatment of the respirable dust in mines and protect the environment.

Abstract: For the non-homogeneous slope with irregular sliding surface, the shear stress on any point of sliding surface is obtained through the static equilibrium relationship of unit body,so the shear potential energy on sliding bed can be calculated in a concise way. In consequence, the improved method for three-dimensional slope stability analysis based on principle of minimum potential energy is put forward. Compared with other three-dimensional methods based on slope examples, the results indicate the following: the safety factor of this method is basically consistent with those of other methods, which shows that this method is feasible. In addition,the method is no need to partition strips and iterate,so the computing process is relatively simple and easy to apply in practical engineering projects.

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