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1. Rotating disc electrode measurements of oxygen reductionreaction on natural massive pyrite in acidic media | |||
CHEN Guobao,YANG Hongying | |||
Metallurgical Engineering 18 March 2016 | |||
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Abstract:In the current study, rotating disk electrode (RDE) measurements were performed to gain insight into the oxygen reduction reaction (ORR) performance of the natural massive pyrite electrode in acidic media. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were also performed. The tafel slopes and electron transferred numbers were calculated according to the test results. The ORR process took place in the potential range of ?0.450 V to 0.050 V vs. AgCl/Ag. The average transferred electron number for ORR on pyrite in sulfuric acid was near to 2. The addition of ferric ion was shown to increase the dissolution rate of pyrite and the transferred electron numbers for ORR. At high concentration of ferric ion, the ORR process was inhibited attributing to a Fenton-like reaction mechanism and more intermediate H2O2 was produced accordingly. | |||
TO cite this article:CHEN Guobao,YANG Hongying. Rotating disc electrode measurements of oxygen reductionreaction on natural massive pyrite in acidic media[OL].[18 March 2016] http://en.paper.edu.cn/en_releasepaper/content/4681002 |
2. Investigation of surface species during bioleaching of chalcopyrite by moderately thermophilic bacteria | |||
WANG Jun,ZHAO Hongbo,TAO Lang,CAO Pan,QIN Wenqing,QIU Guanzhou | |||
Metallurgical Engineering 08 January 2015 | |||
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Abstract: Electrochemical measurement, X-ray diffraction analysis (XRD) and X-ray photoelectron experiment (XPS) analysis were carried out to investigate the surface species and interfacial reactions during bioleaching of chalcopyrite by different strains of moderately thermophilic bacteria. Results showed that CuS and disulfide (S22-) were the main intermediate species on the surface of chalcopyrite during bioleaching by A. caldus, S. thermosulfidooxidans and L. ferriphilum. The low kinetics of dissolution of chalcopyrite in A. caldus can be mainly due to the incomplete dissolution of chalcopyrite and the passivation layer of polysulfide. Polysulfide and jarosite can be mainly responsible for the passivation of chalcopyrite in bioleaching by L. ferriphilum or by S. thermosulfidooxidans. | |||
TO cite this article:WANG Jun,ZHAO Hongbo,TAO Lang, et al. Investigation of surface species during bioleaching of chalcopyrite by moderately thermophilic bacteria[OL].[ 8 January 2015] http://en.paper.edu.cn/en_releasepaper/content/4625972 |
3. Bioleaching of chalcopyrite and marmatite by moderately thermophilic bacteria: An investigation of their interactions Stepwise bioleaching process | |||
WANG Jun,ZHAO Hongbo,TAO Lang,CAO Pan,QIN Wenqing,QIU Guanzhou | |||
Metallurgical Engineering 07 January 2015 | |||
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Abstract: Chalcopyrite and marmatite are associated together most of the time in the raw ores and flotation concentrates. In this work, the interactions between chalcopyrite and marmatite during bioleaching by moderately thermophilic bacteria were investigated mainly by electrochemical measurements and bioleaching experiments. In the initial stage of bioleaching of mixture of chalcopyrite and marmatite, the dissolution of marmatite was preferential, and was significantly accelerated with the addition of chalcopyrite because of the galvanic effect and catalytic effect of Cu2+ ions, while the dissolution of chalcopyrite was inhibited mainly due to the galvanic effect before the accomplishment of dissolution of marmatite. Chalcopyrite dissolved fast when the dissolution of marmatite finished, and small amount of marmatite cannot inhibit the final copper extraction of chalcopyrite if leaching time was long enough. Therefore, stepwise or selective bioleaching was feasible in processing mixture of chalcopyrite and marmatite to avoid complex flotation process in separating chalcopyrite and marmatite. ) | |||
TO cite this article:WANG Jun,ZHAO Hongbo,TAO Lang, et al. Bioleaching of chalcopyrite and marmatite by moderately thermophilic bacteria: An investigation of their interactions Stepwise bioleaching process[OL].[ 7 January 2015] http://en.paper.edu.cn/en_releasepaper/content/4625975 |
4. Solvent extraction of vanadium from a H2SO4-HF mixed acids leaching solution of stone coal | |||
LI Xingbin,WEI Chang,LI Cunxiong,DENG Zhigan,LI Minting,FAN Gang | |||
Metallurgical Engineering 02 November 2014 | |||
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Abstract:Di (2-ethylhexyl) phosphoric acid (P204) and tri-n-butyl phosphate (TBP) were used to extraction vanadium from a H2SO4-HF mixed acids leaching solution of stone coal in this paper. Effect of different operational factors such as equilibrium pH, extractant concentration, extraction stage, strip solution concentration, phase ratio were examined to optimize the condition for selective and quantitative extraction and stripping of vanadium. Based on the results of extraction as well as stripping isotherm, the extraction of vanadium was quantitative in six stages using 10% P204 and 5% TBP at A:O ratio of 1:1 and equilibrium pH of 2.4; 99.6% percentage stripping of vanadium from the loaded organic phase was obtained by five stage stripping using 1.5 mol/L H2SO4 at A:O ratio of 1:8. In the solvent extraction process, scrubbing is necessary for removing co-extracted and entrainment impurities by dilute sulfuric acid solution, more than 90% iron and arsenic can be scrubbed by 0.2 mol/L sulfuric acid. | |||
TO cite this article:LI Xingbin,WEI Chang,LI Cunxiong, et al. Solvent extraction of vanadium from a H2SO4-HF mixed acids leaching solution of stone coal[OL].[ 2 November 2014] http://en.paper.edu.cn/en_releasepaper/content/4616474 |
5. Solvent extraction of vanadium (IV) from sulfuric acid solution using P507 | |||
LI Xingbin,WEI Chang,DENG Zhigan,LI Minting,LI Cunxiong,FAN Gang | |||
Metallurgical Engineering 29 October 2014 | |||
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Abstract:Solvent extractionof vanadium(IV) from sulfuric acid solution has been studied using 2-ethyhexyl phosphonic acid mono 2-ethylhexyl ester (P507) dissolved in kerosene. The different affecting parameters of equilibrium pH, extractant concentration, temperature and extraction isotherm were separately investigated. The extraction of vanadium(IV) from a synthetic sulfuric acid leach solution of stone coal was also examined. The equilibrium study indicated the release of two moles of H+ ions for extraction of one mole of vanadium(IV) and association of two moles of the mono extractant in the extracted species. The extracted complex VOA2 was calculated from slope analysis and confirmed by IR spectra. A positive value of ΔH obtained from temperature variation studies show that the extraction process is endothermic reaction. A continuous counter current simulation extractionand stripping confirmed 96.1% extraction and 99.6% stripping, further attributes to the enrichment 5 times of vanadium(IV) concentration in the strip solution. | |||
TO cite this article:LI Xingbin,WEI Chang,DENG Zhigan, et al. Solvent extraction of vanadium (IV) from sulfuric acid solution using P507[OL].[29 October 2014] http://en.paper.edu.cn/en_releasepaper/content/4615430 |
6. Numerical study of force distribution/transmission in defected smooth hard-sphere crystal | |||
AN Xizhong,YANG Runyu,YU Aibing | |||
Metallurgical Engineering 23 January 2011 | |||
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Abstract:Using discrete element method (DEM), we present the force distribution/transmission in three dimensional (3D) hard-sphere crystal formed by packing of smooth particles under 3D vibration with batch-wised feeding. The distribution P(F) of large forces between spheres and the base is compared with experimental results and shows good agreement. The results show different force behavior at void defect and twin structure (caused by stacking fault), where the former creates effects on P(F) and makes its shape of either in plane or inter plane force distribution curve much broader along the packing height; and the latter can only change the force orientation and no influence on the shape of P(F) distribution. On the other hand, the forces in perfect smooth hard sphere crystal transmitted along the lattice direction, which agrees well with experimental and numerical results on ordered packing. | |||
TO cite this article:AN Xizhong,YANG Runyu,YU Aibing. Numerical study of force distribution/transmission in defected smooth hard-sphere crystal[OL].[23 January 2011] http://en.paper.edu.cn/en_releasepaper/content/4408624 |
7. Experimental Study on the Densification of two-dimensional Vibrated Equal Spheres | |||
AN Xizhong,LI Changxing,YANG Runyu,YU Aibing | |||
Metallurgical Engineering 23 January 2011 | |||
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Abstract:Densification of mono-sized sphere packings under two-dimensional (2D) vibration is experimentally studied. The effects of operation conditions, such as vibration amplitude and frequency, feeding method, vibration mode and container size on packing density are systematically analyzed. The results indicate that much denser packings than random close packing can be achieved by proper control of both vibration amplitude and frequency. Feeding method also plays an important role in densification. Higher packing density can be obtained when the number of particles fed per batch NB is less than or equal to one layer when in interval vibration mode. Packing density decreases with the increase of NB and keeps constant when NB is more than three layers per batch. However, even this, the packing density is also much higher than that in total feeding with corresponding to continuous vibration, which indicates that the interval vibration is more effective than continuous vibration to realize the very dense packing. Through the extrapolation on packing density obtained from different sized containers, the maximum packing density is 0.6757 for the total feeding method and 0.7131 for the batch-wise feeding. Partially ordered structures are observed in the final packings. | |||
TO cite this article:AN Xizhong,LI Changxing,YANG Runyu, et al. Experimental Study on the Densification of two-dimensional Vibrated Equal Spheres[OL].[23 January 2011] http://en.paper.edu.cn/en_releasepaper/content/4408567 |
8. Isotherm, kinetics and thermodynamic studies of adsorption of Cu2+ from aqueous solutions by Mg2+/K+ type orange peel adsorbents | |||
Guo Xueyi,Liang Sha,Feng Ningchuan,Tian Qinghua | |||
Metallurgical Engineering 03 July 2009 | |||
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Abstract:Orange peel was used as raw material to prepare two novel orange peel adsorbents MgOP and KOP. FTIR and SEM were used to characterize the adsorbents. Effects of pH, solid/liquid ratio, time and metal ion concentration on the Cu2+ adsorption were investigated by these two adsorbents. The equilibrium data were analyzed by using Langmuir, Freudlich, Temkin and Dubinin-Radushkevich models. Langmuir model provides the best correlation for the adsorption of Cu2+ by both MgOP and KOP, and the mono-layer adsorption capacity for Cu2+ removal by MOP and KOP are 40.37 and 59.77mg/g, respectively. The adsorbed amounts of Cu2+ increased with the increase in contact time and reached equilibrium within 20min. Kinetics data were analyzed using four adsorption kinetic models: the pseudo-first and second-order equations, the Elovich equation and intraparticle diffusion equation. The experimental data fit well the pseudo-second-order equation, which indicates the adsorption of Cu2+ by MgOP and KOP may follow a chemisorption mechanism. Thermodynamic studies showed the spontaneous, exothermic nature of the adsorption of Cu2+ by MgOP and KOP. | |||
TO cite this article:Guo Xueyi,Liang Sha,Feng Ningchuan, et al. Isotherm, kinetics and thermodynamic studies of adsorption of Cu2+ from aqueous solutions by Mg2+/K+ type orange peel adsorbents [OL].[ 3 July 2009] http://en.paper.edu.cn/en_releasepaper/content/33622 |
9. Researches on sodium-modification of Hunyuan Ca-based bentonite by suspension method | |||
zhang yuanbo,chen liyong,li guanghui,li qian,jiang tao | |||
Metallurgical Engineering 15 June 2009 | |||
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Abstract:Being high dispersity, hydrophilic property and viscosity, bentonite is widely used in the pellet production. Hunyuan bentonite is one of large-type bentonite deposits in China, the reserve of which is more than 0.15 billion tons. However, it is a kind of typical Ca-bentonite (Ca-Bent), not completely utilized in the pellets presently. The sodium-modification of the Ca-bent is investigated by means of suspend liquid in this paper. To begin with, the process mineralogy of the sample is carried out, based on which, different factors (sodium agent and dosage, pulp density, sodium temperature and sodium time, etc.) affecting the sodium-modification are researched. The results show that the alkali coefficient K of modified bentonite is increased from 0.34 to 1.33, and the 2HWA, dilation and colloid index are respectively increased to 601%, 32.4mL/g and 87.6mL/(3g) under the optimal conditions of Na2CO3 dosage 3.0%, pulp density 20%, sodium temperature 55℃ and sodium time 0.5h. The XRD patterns of the bentonite before and after sodium-modification show the d(001) from 1.5539nm reduces to 1.2467nm, and 2θ(001) from 5.6875° increases to 7.0907°, indicating that the Hunyuan Ca-bent is effectively modified into Na-Bent. This investigation can provide a feasible route for the utilization of Hunyuan bentonite. | |||
TO cite this article:zhang yuanbo,chen liyong,li guanghui, et al. Researches on sodium-modification of Hunyuan Ca-based bentonite by suspension method[OL].[15 June 2009] http://en.paper.edu.cn/en_releasepaper/content/33155 |
10. Preparation and evaluation of orange peel xanthate for effective removal of heavy metals from aqueous solutions | |||
Guo Xueyi,Liang Sha,Feng Ningchuan,Tian Qinghua | |||
Metallurgical Engineering 02 April 2009 | |||
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Abstract:The preparation of orange peel xanthate and its adsorption behaviors of heavy metals: Cu2+, Cd2+, Pb2+, Zn2+, Ni2+ were studied. FTIR spectrum and zeta potentials were used to characterize the prepared orange peel xanthate. Effects of various parameters including equilibrium pH, initial ion concentration and contact time on the adsorption processes for the five metal ions were investigated. For all five metal ions, adsorption isotherms were found to fit Langmuir model and the maximum adsorption capacities of Cu2+, Cd2+, Pb2+, Zn2+ and Ni2+ were obtained as 77.60, 76.57, 218.34, 49.85 and 15.45 mg•g-1, respectively. All adsorption processes can attain equilibrium within 20 min and kinetics was well fitted by psesudo-second order equation. It is proposed that the adsorption mechanism was complexation. | |||
TO cite this article:Guo Xueyi,Liang Sha,Feng Ningchuan, et al. Preparation and evaluation of orange peel xanthate for effective removal of heavy metals from aqueous solutions [OL].[ 2 April 2009] http://en.paper.edu.cn/en_releasepaper/content/31025 |
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