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Feng Q.,Kunming University of Science and Technology | Zhao W.,Kunming Metallurgical Research Institute | Wen S.,Kunming University of Science and Technology | Cao Q.,Kunming University of Science and Technology
Separation and Purification Technology | Year: 2017

The effect of lead ions on cassiterite flotation with salicylhydroxamic acid as collector was assessed by a combination of microflotation tests, adsorption experiments, zeta-potential determinations, and X-ray photoelectron spectroscopy (XPS) analysis in this work. Microflotation tests confirmed the contribution of lead ions to cassiterite flotation at an increased floatability of 12.12% compared with that in the absence of lead ions. The adsorption experiments demonstrated that the adsorbed amount of SHA onto cassiterite surfaces was greatly increased after treatment with lead ions. The results of zeta-potential determinations indicated that the cassiterite surface was activated by the adsorption of lead species in the form of Pb(OH)+, and the higher adsorption capacity of SHA onto the mineral surface was obtained after modifying with lead ions. XPS analysis revealed that lead ions adsorbed onto the mineral surface through the interaction between lead species and oxygen sites of cassiterite surfaces. This occurrence increased the number of active sites on the mineral surface and improved the collector attachment. These results consistently indicated that the activity of the cassiterite surface increased after pretreatment with lead ions and enhanced the flotation behavior. © 2017 Elsevier B.V.


Nie Z.-F.,Kunming University of Science and Technology | Xie G.,Kunming University of Science and Technology | Xie G.,Kunming Metallurgical Research Institute | Hou Y.-Q.,Kunming University of Science and Technology | And 3 more authors.
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2014

The simulation of convection heat transfer and radiation heat transfer in the Siemens reactor with 12 pairs of rods has been investigated by computational fluid dynamic (CFD) in the paper, in which a 3D physical model of mass transfer, momentum transfer, heat transfer with radiation was considered. By comparing calculated results with the experimental data measured by manufacturing enterprise, the relative error was 7.1%, which confirmed the model valid since the relative error was within 10%. Based on Discrete Ordinates (DO) radiation model, the radiation exchange between the hot polysilicon rods and the reactor wall was analyzed in detail, and especially the power radiated by the characteristic rods of every ring to the wall and influence of the wall emissivity were also studied. The results show that the radiation heat exchange is the main power consumed in the CVD reactor. The power radiated by the characteristic rod of outer ring is larger than that of inner ring, which increases with the diameter of silicon rod. The power radiated by polysilicon rods in the deposition process increases with the emissivity of the reactor wall, and the unit energy comsumption is obtained for different reactor wall emissivities.


Wu Z.,Kunming University of Science and Technology | Hu L.,Kunming University of Science and Technology | Chen J.,Kunming metallurgical research institute
Advanced Materials Research | Year: 2013

Surface hydrophobic modification of T-ZnOw was experimented with silane coupling agent KH-570(gamma-(methylpropyl acyloxy)trimethoxysilane). It was shown by FT-IR that the whiskers was modified by silane coupling agents molecular compounded with the Zn-OH of whiskers. The effect of grafted modification with KH570 on hydrophobicity of T-ZnOw was characterized with dispersion stability test in an organic solvent and measuring the contact angle between the whiskers on distilled water. The results showed that surface treatment of T-ZnOw with KH570 improves hydrophobicity of whiskers simultaneously, and the modified whiskers have much slower settling rates than the pristine whiskers in the liquid paraffin. The contact angle between the modified whiskers with distilled water is 137.75o, which is a significant increase © (2013) Trans Tech Publications, Switzerland.


Han F.,Kunming University of Science and Technology | Lei T.,Kunming Metallurgy College | Zhou L.,Kunming Metallurgical Research Institute | Huang S.,Kunming University of Science and Technology | Lu G.,Kunming University of Science and Technology
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2012

The adequate carbon should be fed as reductant in order to achieve qualified titanium slag, and deoxidized the highoxide to lowoxide. The domestic first 30 MVA DC arc furnace of a company in Yunnan province obtained the favorable slag by controlling the ratio of anthracite to ilmenite (AIR), in the case of certain energy input and stable component of ilmenite. The ilmenite and anthracite were put into DC furnace through hollow graphite electrode, meanwhile it was needed to control temperature between 1973 K and 2023 K, 15 MVA of input power, 0.1~0.33 mm of partical size of ilmenite, the ratio of anthracite partical size range of 5~25 mm were more than 85%. Theoretically, deoxidizing 1t ilmenite would produce 526 kg titanium slag and 368 kg iron, and Output/Input rate was about 89.4%, the theory AIR was about 7.895%. Calculated on mass balance, the mean AIR during the smelting period was 12.228%, and output/input rate was 81.317%. With the short of anthracite, the oxygen of FeO in ilmenite would be easy to dissociate and combine with carbon; in this case, the reduction reaction of FeO would be prior to TiO 2. On the other hand, with more carbon, the carbon will be used for deoxidizing the oxide that are difficult to reducte, for example, MgO, CaO, MnO and so on, and the reduction of FeO would be restrained. AIR also effects on the fluidity of molten slag and freeze lining. The content of TiO 2 in the titanium slag increased to more than 89% from 82% in the trial by modulating the AIR.


Feng Q.,Kunming University of Science and Technology | Wen S.,Kunming University of Science and Technology | Zhao W.,Kunming Metallurgical Research Institute | Deng J.,Kunming University of Science and Technology | Xian Y.,Kunming University of Science and Technology
Applied Surface Science | Year: 2016

The adsorption of sulfide ions on cerussite surfaces and implications for flotation were studied by X-ray photoelectron spectroscopy (XPS) analysis, micro-flotation tests, and surface adsorption experiments. The XPS analysis results indicated that lead sulfide species formed on the mineral surface after treatment by Na2S, and the increase in the Na2S concentration was beneficial for sulfidization. In addition to the content of lead sulfide species, its activity, which was determined by the proportion of sulfide, disulfide and polysulfide, also played an important role in cerussite sulfidization. Micro-flotation tests results demonstrated that insufficient or excessive addition of Na2S in pulp solutions has detrimental effects on flotation performance, which was attributed to the dosage of Na2S and the activity of lead sulfide species formed on the mineral surface. Surface adsorption experiments of sulfide ions determined the residual S concentrations in pulp solutions and provided a quantitative illustration for the inhibition of cerussite flotation by excessive sulfide ions. Moreover, it also revealed that sulfide ions in the pulp solution were transformed onto the mineral surface and formed lead sulfide species. These results showed that both of lead sulfide species and its activity acted as an important role in sulfidization flotation process of cerussite. © 2015 Elsevier B.V. All rights reserved.


Feng Q.,Kunming University of Science and Technology | Wen S.,Kunming University of Science and Technology | Zhao W.,Kunming Metallurgical Research Institute | Wang Y.,Kunming University of Science and Technology | Cui C.,Kunming University of Science and Technology
Minerals Engineering | Year: 2015

The effect of the addition of chloride ions on the sulfidization flotation of cerussite was investigated by micro-flotation tests, surface adsorption experiments, zeta potential measurements, and X-ray photoelectron spectroscopy (XPS) analysis. The micro-flotation test results indicated that the addition of chloride ions prior to sulfidization significantly increased the flotation recovery of cerussite. The maximum and minimum percentages of increase in flotation recovery were 16.63% and 10.51%, respectively. Surface adsorption experiments of sulfide demonstrated that there was a higher adsorption concentration of S species on the mineral surface, and its adsorption efficiency was enhanced. The results of zeta potential measurements revealed that the addition of Na2S and chloride ions to the solution caused a more negative zeta potential than the addition of Na2S alone. The XPS analysis results indicated that more lead sulfide formed on the mineral surface after the addition of chloride ions into the pulp solution. These results consistently showed that the addition of chloride ions played a significant role in the sulfidization of cerussite, resulting in a better flotation performance. © 2015 Elsevier Ltd.


Jiang Y.-J.,Pioneer Corporation | Cui Q.-X.,Pioneer Corporation | Mao Y.-P.,Kunming Metallurgical Research Institute
Yejin Fenxi/Metallurgical Analysis | Year: 2015

The determination of trace copper and vanadium in titanium dioxide sample by inductively coupled plasma atomic emission spectrometry (ICP-AES) was interfered with the titanium matrix. The titanium matrix was precipitated and separated by diammonium hydrogen phosphate [(NH4)2HPO4]. Then, the content of trace copper and vanadium in titanium dioxide sample was determined by ICP-AES. The sample dissolution method, the precipitation conditions of titanium with (NH4)2HPO4 and the determination conditions of ICP-AES were investigated. The results showed that the titanium in 0.1 g of titanium dioxide sample could be fully react with (NH4)2HPO4 to form Ti(HPO4)2 precipitate in ammonium sulfate and sulfuric acid medium after heating in boiling bath for 3-5 min. The determination results were stable under the selected instrumental conditions with Cu 327.4 nm and V 292.4 nm as analytical spectral line. The detection limit of copper and vanadium was 0.001 μg/mL and 0.000 7 μg/mL, respectively. The proposed method was applied to determination of copper and vanadium in titanium dioxide actual samples. The relative standard deviation (RSD) was not more than 1.2%, and the recoveries were between 90% and 117%. The proposed method was applicable for the routine analysis of titanium dioxide. ©, 2015, Central Iron and Steel Research Institute. All right reserved.


Shen Y.-X.,CAS Xishuangbanna Tropical Botanical Garden | Liu W.-L.,Kunming Metallurgical Research Institute | Li Y.-H.,Yunnan Normal University | Guan H.-L.,Yunnan Normal University
PLoS ONE | Year: 2014

A large number of small-sized samples invariably shows that woody species are absent from forest soil seed banks, leading to a large discrepancy with the seedling bank on the forest floor. We ask: 1) Does this conventional sampling strategy limit the detection of seeds of woody species? 2) Are large sample areas and sample sizes needed for higher recovery of seeds of woody species? We collected 100 samples that were 10 cm (length) x10 cm (width) x10 cm (depth), referred to as larger number of small-sized samples (LNSS) in a 1 ha forest plot, and placed them to germinate in a greenhouse, and collected 30 samples that were 1 m x1 mx10 cm, referred to as small number of large-sized samples (SNLS) and placed them (10 each) in a nearby secondary forest, shrub land and grass land. Only 15.7% of woody plant species of the forest stand were detected by the 100 LNSS, contrasting with 22.9%, 37.3% and 20.5% woody plant species being detected by SNLS in the secondary forest, shrub land and grassland, respectively. The increased number of species vs. sampled areas confirmed power-law relationships for forest stand, the LNSS and SNLS at all three recipient sites. Our results, although based on one forest, indicate that conventional LNSS did not yield a high percentage of detection for woody species, but SNLS strategy yielded a higher percentage of detection for woody species in the seed bank if samples were exposed to a better field germination environment. A 4 m2 minimum sample area derived from power equations is larger than the sampled area in most studies in the literature. Increased sample size also is needed to obtain an increased sample area if the number of samples is to remain relatively low. © 2014 Shen et al.


Li M.,Kunming Metallurgical Research Institute | Jian S.,Kunming Metallurgical Research Institute | Zhao W.,Kunming Metallurgical Research Institute
Applied Mechanics and Materials | Year: 2013

The zinc oxide sample from the Lanping mine located in the west of Yunnan province, China, is characterized with low grade, high calcium content, high oxidation rate and heavy slime. According to the properties of the ore, a new dressing-metallurgy combined method is proposed to process the ore and the beneficiation part is discussed by this paper. Based on the regulation of reagent scheme, flotation flowsheet of pre-desliming and two rougher is conducted to obtain a zinc concentrate that Zn grade is 18.72% at Zn recovery of 90.88%. The calcium removal rate of zinc concentrate reaches to as high as 78.15% for the flotation operation, which could lay the foundation for the next acid leaching process. © (2013) Trans Tech Publications, Switzerland.


PubMed | CAS Xishuangbanna Tropical Botanical Garden, Kunming Metallurgical Research Institute and Yunnan Normal University
Type: Journal Article | Journal: PloS one | Year: 2014

A large number of small-sized samples invariably shows that woody species are absent from forest soil seed banks, leading to a large discrepancy with the seedling bank on the forest floor. We ask: 1) Does this conventional sampling strategy limit the detection of seeds of woody species? 2) Are large sample areas and sample sizes needed for higher recovery of seeds of woody species? We collected 100 samples that were 10 cm (length) 10 cm (width) 10 cm (depth), referred to as larger number of small-sized samples (LNSS) in a 1 ha forest plot, and placed them to germinate in a greenhouse, and collected 30 samples that were 1 m 1 m 10 cm, referred to as small number of large-sized samples (SNLS) and placed them (10 each) in a nearby secondary forest, shrub land and grass land. Only 15.7% of woody plant species of the forest stand were detected by the 100 LNSS, contrasting with 22.9%, 37.3% and 20.5% woody plant species being detected by SNLS in the secondary forest, shrub land and grassland, respectively. The increased number of species vs. sampled areas confirmed power-law relationships for forest stand, the LNSS and SNLS at all three recipient sites. Our results, although based on one forest, indicate that conventional LNSS did not yield a high percentage of detection for woody species, but SNLS strategy yielded a higher percentage of detection for woody species in the seed bank if samples were exposed to a better field germination environment. A 4 m2 minimum sample area derived from power equations is larger than the sampled area in most studies in the literature. Increased sample size also is needed to obtain an increased sample area if the number of samples is to remain relatively low.

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