Cleaner Metallurgical Engineering Research Center

Industry of, China

Cleaner Metallurgical Engineering Research Center

Industry of, China
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Tian Q.,Central South University | Tian Q.,Cleaner Metallurgical Engineering Research Center | Wang X.,Central South University | Huang G.,Central South University | And 3 more authors.
Nanoscale Research Letters | Year: 2017

Nanostructured Co doped Mn3O4 spinel structure ((Co, Mn)3O4) were prepared by co-precipitation under O3 oxidizing conditions and post-heat treatment. The product was composed of nanogranules with a diameter of 20–60 nm. The electrochemical performance of (Co, Mn)3O4 electrode was tested by cyclic voltammetry, impedance, and galvanostatic charge-discharge measurements. A maximum specific capacitance value of 2701.0 F g−1 at a current density of 5 A g−1 could be obtained within the potential range from 0.01 to 0.55 V versus Hg/HgO electrode in 6 mol L−1 KOH electrolyte. When at high current density of 30 A g−1, the capacitance is 1537.2 F g−1 or 56.9% of the specific capacitance at 5 A g−1, indicating its good rate capability. After 500 cycles at 20 A g−1, the specific capacitance remains 1324 F g−1 with a capacitance retention of 76.4%. © 2017, The Author(s).


Tian Q.,Central South University | Tian Q.,Cleaner Metallurgical Engineering Research Center | Xin Y.,Central South University | Xin Y.,Cleaner Metallurgical Engineering Research Center | And 4 more authors.
Hydrometallurgy | Year: 2017

In this study, manganese and cobalt were selectively separated and recovered from zinc in a leaching solution of cobalt slag by potential-controlled oxidation with ozone. The separation mechanism was discussed. When ozone was pumped into the solution, the manganese (II) was first oxidized and precipitated. After the precipitated manganese is removed from the solution, the cobalt (II) in the solution was oxidized and separated in the same way. Partial zinc was also lost in the precipitates in the form of encapsulated inclusions. The effects of dilution ratio, solution pH values, system temperatures on the manganese and cobalt recoveries were investigated. High recovery rates of cobalt and manganese were achieved, high-grade cobalt precipitate and highly purified liquid were obtained at optimized conditions. © 2017


Guo X.,Central South University | Guo X.,Cleaner Metallurgical Engineering Research Center | Yan K.,Central South University | Yan K.,Cleaner Metallurgical Engineering Research Center
Science of the Total Environment | Year: 2017

Rapid development of electronic technique has led to decreasing lifespan of electronic products. Meanwhile, the amount of waste electrical and electronic equipment (WEEE) is rapidly growing in recent years especially in China. The generation amount of WEEE is one of the basic information for waste management. In our study, the generation of obsolete cellular phones and metals containing of cellular phones were estimated from 1997 to 2025. The future average possession in per 100 inhabitants of cellular phones was predicted using logistic model. Moreover, the lifespan distribution of cellular phones was analyzed using Weibull distribution. Meanwhile, the generation amount of obsolete cellular phones and its metals containing were estimated by using population balance model (PBM) and substance flow analysis (SFA), respectively. The estimated results indicate that the average possession in per 100 inhabitants will reach to 111.2 and 118.3 units in 2020 and 2025, respectively, which is about two times higher than the average possession in 2010. In addition, the total possession amount of cellular phones are expected to exceed 1.64 billion units in 2025. Moreover, the estimated results show that 781 million units obsolete cellular phones were generated in 2015, and the number will grow up to 877 and 937 million units in 2020 and 2025, respectively. In 2025, the total weight of annual generation amount of obsolete cellular phones will exceed 140 Gg. The precious metals such as silver, gold contains in obsolete cellular phones will reach 56,250 and 28,130 kg, respectively, in 2025. The obsolete cellular phones are the typical secondary metal resources especially for precious metals. In order to improve the recycling efficiency, it is necessary to establish a comprehensive system of waste management. © 2016


Yang Y.,Central South University | Yang Y.,Cleaner Metallurgical Engineering Research Center | Gao J.,Central South University | Gao J.,Cleaner Metallurgical Engineering Research Center | And 5 more authors.
Solid State Ionics | Year: 2015

Abstract In this work the effects of Co3O4 concentration on the properties of agarose polymer electrolyte and the corresponding DSSCs are studied with/without magnetic field treatments. The surface morphology, ion concentration, and ionic conductivity of agarose electrolytes with different Co3O4 concentrations are compared under 0 and 35 mT magnetic field using various characterization methods. The photovoltaic performances of quasi-solid-state DSSCs with Co3O4 modified polymer electrolyte are examined. After applying magnetic fields, the ionic conductivity and photo-to-electric conversion efficiency of DSSCs are obviously improved in the Co3O4 concentrations below 4 wt.%. The highest ionic conductivity of 6.00 mS cm- 1 is obtained with electrolyte modified by 3 wt.% Co3O4. The DSSCs with the optimal Co3O4 content show the best conversion efficiency under both 0 and 35 mT magnetic fields. © 2015 Elsevier B.V.


Xiao S.,Central South University | Xiao S.,Cleaner Metallurgical Engineering Research Center | Cui J.,Central South University | Yi P.,Central South University | And 4 more authors.
Electrochimica Acta | Year: 2014

Agarose-based electrolyte containing magnetic Co3O4nanoparticles is studied for quasi-solid-state dye-sensitized solar cells (DSSCs) under external magnetic field treatment. SEM studies reveal the existence of oriented microstructure in Co3O4-modified agarose electrolyte film under proper magnetic field intensity. The formation mechanism of this ordered structure induced by magnetic field is analyzed. The impedance analysis shows that the ionic conductivity of Co3O4-modified agarose electrolyte is obviously increased by applying magnetic field intensity of 25 mT. Improved electron recombination process and photoelectric performance are observed in DSSCs under certain magnetic field treatment by electrochemical impedance spectra (EIS) and photovoltaic studies. The DSSC treated with magnetic field can maintain the efficiency unchanged for 434 hours without sealing. This is attributed to the high ionic conductivity and improved electron transfer process in DSSC resulting from the magnetic field treatment. Comparison of photovoltaic performances for Co3O4and NiO modified DSSCs under 25 mT magnetic field treatment shows that Co3O4-modified DSSC exhibits higher energy conversion efficiency than that of NiO-modified one at the same condition. © 2014 Elsevier Ltd. All rights reserved.


Guo X.,Central South University | Guo X.,Cleaner Metallurgical Engineering Research Center | Liu J.,Central South University | Qin H.,Central South University | And 5 more authors.
Hydrometallurgy | Year: 2015

An efficient alkali fusion-leaching-separation process is developed to recover metals in crushed metal enrichment (CME) which originated from waste printed circuit boards (PCBs). Impacts of fusion parameters on metals conversions were systematically investigated. In the fusion-leaching process, amphoteric metals such as tin, lead, zinc and aluminum in the CME were leached out, while leaving copper and precious metals in the residue. Subsequently, metals in solution were further extracted via precipitation processes, and metals in the residue were recovered using an acid leaching-electrowinning process. Cathode copper, nano-Cu2O, CaSnO3/CaSn(OH)6 crystal and mixture of PbS-ZnS were obtained as the final products of this process. By optimizing the experimental conditions, recoveries of 98.66% for Cu, 91.08% for Sn, 91.25% for Zn, 78.78% for Pb were achieved, respectively. And all precious metals were enriched in the final residue with grades of Au 613 g/t, and Ag 2157 g/t. © 2015 Elsevier B.V. All rights reserved.


Tian Q.,Central South University | Tian Q.,Cleaner Metallurgical Engineering Research Center | Wang H.,Central South University | Xin Y.,Central South University | And 4 more authors.
Hydrometallurgy | Year: 2016

Selective dissolution of stibnite from a complex sulfidic antimony ore containing pyrite by ozonation leaching in hydrochloric acid solution has been studied in the paper. Effects of hydrochloric acid concentration, leaching time, temperature, gas (ozone and oxygen mixture) flow rate and liquid/solid ratio on antimony extraction and iron dissolution have been examined. The results show that the leaching efficiency (%) of antimony increases with the temperature (from 35 °C to 65 °C) and hydrochloric acid concentration (from 3.0 mol/L to 4.5 mol/L). In comparison, the iron dissolution remains constant in these ranges. In addition, it is noted that the decomposition of stibnite is easier than that of pyrite. High antimony extraction (94.3%) with low iron dissolution (2.3%) is achieved under the following leaching conditions: 4.5 mol/L hydrochloric acid concentration, 2.0 L/min gas flow rate and 8:1 of the L/S ratio, leaching for 4.0 h at 65 °C. These results reveal that ozonation leaching of the complex sulfidic antimony ore in hydrochloric acid solution is a promising technology. © 2015 Elsevier B.V. All rights reserved.


Tian Q.,Central South University | Tian Q.,Cleaner Metallurgical Engineering Research Center | Wang H.,Central South University | Xin Y.,Central South University | And 6 more authors.
Hydrometallurgy | Year: 2016

A novel leaching process for stibnite concentrates using ozone as oxidant has been studied in this paper. The main factors affecting the leaching rate such as leaching temperature, concentration of leaching agent, gas flow rate and liquid to solid ratio have been investigated comprehensively. In addition, the effect of ferric chloride and sodium chloride on antimony extraction has been studied. The results indicate that the leaching efficiency (%) of the antimony increases with the increase of those factors mentioned above. And the form that the antimony dissolves into solution is SbCln 3-n, while the sulfur mainly retains in the residue in the form of sulfur element. The oxidation leaching of stibnite concentrates has achieved antimony recoveries in excess of 99% under the optimum experimental conditions after 5h of leaching. © 2016 Elsevier B.V.


Cui J.,Central South University | Yang Y.,Central South University | Yang Y.,Cleaner Metallurgical Engineering Research Center | Yi P.,Central South University | And 2 more authors.
Journal of Power Sources | Year: 2014

In this paper, the effect of p-n junction additives via blending p-type semiconductors (NiO and CuI) with n-type TiO2in polymer electrolyte on quasi-solid-state DSSCs is studied. The conduction mechanism of DSSCs modified with random p-n junctions has been investigated by FTIR, SEM, UV-Vis and electrochemical analysis. The results indicate that the CuI-TiO2p-n blend modified polymer electrolyte reaches the maximum ionic conductivity of 6.44 mS cm-1, which is almost twice over than that of pure-TiO2modified one. From photovoltaic study, it is found that introducing CuI-TiO2and NiO-TiO2p-n blends in polymer electrolyte can obviously improve electron recombination and light-to-electric conversion efficiency of DSSCs. The conversion efficiency of CuI-TiO2p-n blend modified DSSC is 3.34%, which is much higher than that of pure TiO2modified device (1.76%). It is also demonstrated that the photovoltaic properties of DSSCs directly depends on the ratio of p-type CuI and n-type TiO2in the p-n blends and the optimal conversion efficiency of 4.27% is obtained at CuI:TiO2ratio of 4:1. © 2014 Elsevier B.V. All rights reserved.


Yan K.,Central South University | Yan K.,Cleaner Metallurgical Engineering Research Center | Guo X.Y.,Central South University | Guo X.Y.,Cleaner Metallurgical Engineering Research Center | And 4 more authors.
Materials Science Forum | Year: 2015

Substance flow analysis (SFA) of cobalt in China was carried out to analyze cobalt flows and stocks by using static SFA. Cobalt can be widely used in industry due to its high-melting point, high-strength, and well magnetism. In this static model, the relationship among inflows, outflows and stocks throughout the whole cobalt life-cycle in China were identified. According to the static model, the amount was calculated in the form of cobalt metal, in 2012, 29784t of cobalt was produced, and 30700t of cobalt was imported, 9400t exported and domestic consumption was 31700t, 9000t stocks of cobalt was consumed and 3000t old scrap was recycled in China. The ore index and recovery scrap resource of cobalt industry were 0.318 t/t and 0.136 t/t respectively. © (2015) Trans Tech Publications, Switzerland.

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