Liu J.L.,Kunming University of Science and Technology |
Liu J.L.,Yunnan Xinli Nonferrous Metals Co. |
Hu J.,Kunming University of Science and Technology |
Wang K.J.,Kunming University of Science and Technology |
Zhu X.Q.,Kunming University of Science and Technology
Advanced Materials Research | Year: 2010
This paper puts forward a new method for the preparation of 99.999% high-purity alumina used for the LED underlay sapphire, which has above 99.999% high-purity aluminum atomized the active aluminum powder by the supersonic multistage cooling way, then makes the powder form the hydrate of the alumina through the hydrolyzing reaction, and finally gets 99.999% high-purity alumina by means of the calcinations and the follow-up granularity treatment. By the processing way, the reactant is only aluminum and water, and there is no other additive, which profitably keeps the product pure and completely satisfies the requirements of synthetic crystals while tested. © (2010) Trans Tech Publications.
Long X.,Yunnan Xinli Nonferrous Metals Co. |
Long X.,Central South University |
Chen W.,Central South University |
Ye H.-Q.,Central South University
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2011
Lamellar aluminium oxide single crystal particle were successfully calcinated Al(OH)3 as precursor, which was produced by sol-gel method using Al2(SO4)3·18H2O as raw material and adding small-amount of TiO2, Na3PO4, K2SO4, etc, as flux. The morphology, particle size and phase composition of aluminium oxide powder were analyzed by optical microscope, granulometer and XRD. The effects of molten salt system, calcinate temperature and additives on the particle size and morphology of aluminium oxide powder were studied. It is found that hexagonal lamellate α-Al2O3 powder with perfect morphology, smooth surface, good dispersion property, good plarlitic effect, particle size of 4~15 μm (average of 10.613 μm), thickness of about 150~300 nm and aspect ratio of 25~40 can be obtained, using composite (Na2SO4-K2SO4) as flux system, adding 3.0% sodium phosphate and 1.0% TiO2 as additives, and calcinated at 1200°C for 5 h.
Cui Q.-X.,Yunnan Xinli Nonferrous Metals Co. |
Xie H.-B.,Yunnan Xinli Nonferrous Metals Co. |
Mao Y.-P.,Kunming Metallurgical Research Institute
Yejin Fenxi/Metallurgical Analysis | Year: 2014
A simple and accurate determination method of trace and ultratrace arsenic in zirconium oxychloride (ZrOCl2.8H2O) was proposed. According to the content of arsenic in sample, less than 10 g of sample was put into a simple distillator. After adding certain amount of hydrochloric acid (containing little potassium bromide and ferrous sulfate), the sample was heated and decomposed. The distilled arsenic trichloride was absorbed with cold water. After dilution to constant volume, the content of arsenic in solution was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) under selected instrumental conditions. The response intensity of arsenic was in direct ratio to its concentration in range of 0.0-10.0μg/mL. The correlation coefficient of calibration curve (r) was higher than 0.999 9. The recoveries of standard addition were between 99% and 112%. The relative standard deviation (RSD, n=5) was in range of 0.5%-2.0%. The proposed method was applied to the determination of trace and ultratrace arsenic in zirconium oxychloride. The found results were consistent with those obtained by catalytic polarography or atomic fluorescence spectrometry. ©, 2014, Central Iron and Steel Research Institute. All right reserved.
Pu X.-W.,Yunnan Xinli Nonferrous Metals Co. |
Jiang Y.-J.,Yunnan Xinli Nonferrous Metals Co. |
Cui Q.-X.,Yunnan Xinli Nonferrous Metals Co. |
Mao Y.-P.,Kunming Metallurgy Research Institute
Yejin Fenxi/Metallurgical Analysis | Year: 2013
In sulfuric acid medium at pH3.2-3.5, Ti(IV) reacted with fluorinion to form H2TiF6, resulting in the decoloration of yellow complex(TiO · H2O2)SO4 formed by TiQV) and H2O2. In addition, the decoloration degree was linear to the content of fluorinion. In view of the above, a decoloration photometry for the determination of fluorine content in fused salt was proposed. The sample was fused with mixed flux (zinc oxide, sodium carbonate and quartz sand). After leaching with water and filtration, proper amount of solution was sampled. Titanium dioxide solution was added, and the pH was adjusted with sulfuric acid. Then, the hydrogen peroxide solution was added. After reaction for 15 min, the absorbance was measured at 410 nm. When the fluorinion amount was in the range of 0.5-6 μg/niL, the calibration curve showed linearity, with correlation coefficient of r=0.9996. The detection limit of method was 0.35 μg/mL. For 0.5 μg/mL fluorinion, 5-fold of SO4 2-, 10-fold of Na+, and 20-fold of K+ and Cl- had no interference. Ca2+, Fe3+ and Mg2+ in fused salt sample had been precipitated and separated after fusion, so they did not interfere in the determination. The fluorine content in two fused salts from magnesium electrolysis plant of sponge titanium factory was determined by the proposed method. The results were consistent with those obtained by fluorine ion-selective electrode method and polarography. The relative standard deviation (RSD, n=5) was 2.2% and 4.2%, respectively.