A novel pre-treatment of calaverite by hydrothermal mineral replacement reactions / Zhao, Jing in Minerals engineering, Vol. 23 N° 5 (Avril 2010)  

Public ISBD [article]  inMinerals engineering > Vol. 23 N° 5 (Avril 2010) . - pp. 451–453 Titre : A novel pre-treatment of calaverite by hydrothermal mineral replacement reactions Type de document : texte imprimé Auteurs : Zhao, Jing, Auteur ; Fang Xia, Auteur ; Allan Pring, Auteur Année de publication : 2011 Article en page(s) : pp. 451–453 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Precious metal ores Hydrometallurgy Extractive metallurgy Résumé : We report a new method for pre-treatment of refractory gold-bearing tellurides employing the hydrothermal mineral replacement reactions. The method is illustrated by the replacement of calaverite by metallic gold at 150–250 °C under vapor saturated pressures. The influences of temperature, pH, and additional salts (NaCl and Na2SO4) on the conversion rate were investigated using the orthogonal array design method. The results indicate that temperature is the most significant factor, followed by pH, and then additional salts. The optimal condition for fast and low cost conversion is 200 °C, pH 6.0, 0.01 M NaCl, and DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002933 [article] A novel pre-treatment of calaverite by hydrothermal mineral replacement reactions [texte imprimé] / Zhao, Jing, Auteur ; Fang Xia, Auteur ; Allan Pring, Auteur . - 2011 . - pp. 451–453. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 5 (Avril 2010) . - pp. 451–453 Mots-clés : Precious metal ores Hydrometallurgy Extractive metallurgy Résumé : We report a new method for pre-treatment of refractory gold-bearing tellurides employing the hydrothermal mineral replacement reactions. The method is illustrated by the replacement of calaverite by metallic gold at 150–250 °C under vapor saturated pressures. The influences of temperature, pH, and additional salts (NaCl and Na2SO4) on the conversion rate were investigated using the orthogonal array design method. The results indicate that temperature is the most significant factor, followed by pH, and then additional salts. The optimal condition for fast and low cost conversion is 200 °C, pH 6.0, 0.01 M NaCl, and DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002933

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A novel PWM control method for hybrid-clamped multilevel inverters / Zhao, Jing in IEEE transactions on industrial electronics, Vol. 57 N° 7 (Juillet 2010)  

Public ISBD [article]  inIEEE transactions on industrial electronics > Vol. 57 N° 7 (Juillet 2010) . - pp. 2365 - 2373 Titre : A novel PWM control method for hybrid-clamped multilevel inverters Type de document : texte imprimé Auteurs : Zhao, Jing, Auteur ; He, Xiangning, Auteur ; Zhao, Rongxiang, Auteur Article en page(s) : pp. 2365 - 2373 Note générale : Génie électrique Langues : Anglais (eng) Mots-clés : Hybrid clamped Multilevel inverters Pulsewidth modulation (PWM) Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : A novel pulsewidth modulation (PWM) control method is proposed in this paper. The PWM control method is called higher and lower carrier cells alternative phase opposition PWM (HLCCAPOPWM) for the hybrid-clamped multilevel inverter and based on the improvement of carrier phase disposition PWM (PDPWM). The principle of the HLCCAPOPWM method, the comparison with the carrier PDPWM method, and the analysis on output voltage spectrum are given. Simulations and experiments show that comparing with the carrier PDPWM method, the novel method can effectively reduce the number of devices switching on or off within broad modulation index range, consequently reducing switching losses, and remarkably reduce the amplitude of lower harmonics. Simulations also show the generalization of the HLCCAPOPWM method for hybrid-clamped n-level inverters and neutral-point-clamped inverters. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5175404 [article] A novel PWM control method for hybrid-clamped multilevel inverters [texte imprimé] / Zhao, Jing, Auteur ; He, Xiangning, Auteur ; Zhao, Rongxiang, Auteur . - pp. 2365 - 2373. Génie électrique Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 57 N° 7 (Juillet 2010) . - pp. 2365 - 2373 Mots-clés : Hybrid clamped Multilevel inverters Pulsewidth modulation (PWM) Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : A novel pulsewidth modulation (PWM) control method is proposed in this paper. The PWM control method is called higher and lower carrier cells alternative phase opposition PWM (HLCCAPOPWM) for the hybrid-clamped multilevel inverter and based on the improvement of carrier phase disposition PWM (PDPWM). The principle of the HLCCAPOPWM method, the comparison with the carrier PDPWM method, and the analysis on output voltage spectrum are given. Simulations and experiments show that comparing with the carrier PDPWM method, the novel method can effectively reduce the number of devices switching on or off within broad modulation index range, consequently reducing switching losses, and remarkably reduce the amplitude of lower harmonics. Simulations also show the generalization of the HLCCAPOPWM method for hybrid-clamped n-level inverters and neutral-point-clamped inverters. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5175404

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