Significance of liberation characteristics in the fatty acid flotation of Florida phosphate rock / Mohamed I. Al-Wakeel in Minerals engineering, Vol. 22 N° 3 (Fevrier 2009)  

Public ISBD [article]  inMinerals engineering > Vol. 22 N° 3 (Fevrier 2009) . - pp. 244–253 Titre : Significance of liberation characteristics in the fatty acid flotation of Florida phosphate rock Type de document : texte imprimé Auteurs : Mohamed I. Al-Wakeel, Auteur ; C.L. Lin, Auteur ; Jan D. Miller, Auteur Année de publication : 2009 Article en page(s) : pp. 244–253 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth flotation Liberation analysis Mineralogy Florida phosphate rock Index. décimale : 622 Industrie minière Résumé : Phosphate flotation has been used by industry for more than a half century but still faces many technical challenges. Such challenges include not only the selection of the chemical reagents but the characteristics of the feed itself. This paper deals with the investigation of feed characteristics and how these characteristics affect the flotation separation efficiency of feed material from a selected phosphate operation. Specifically why some feed, from the same mine, is efficiently separated with high recovery (good feed) while other feed is more difficult to separate (bad feed). The study was conducted using both traditional analytical techniques and more advanced techniques such as X-ray microtomography. The results reveal that the bad feed was highly porous, coarser in size, and, most significantly, exhibits a lower degree of liberation. Such bad feed was inefficiently separated by fatty acid flotation and improved recovery would require controlled grinding in order to improve the extent of liberation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750800188X [article] Significance of liberation characteristics in the fatty acid flotation of Florida phosphate rock [texte imprimé] / Mohamed I. Al-Wakeel, Auteur ; C.L. Lin, Auteur ; Jan D. Miller, Auteur . - 2009 . - pp. 244–253. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 3 (Fevrier 2009) . - pp. 244–253 Mots-clés : Froth flotation Liberation analysis Mineralogy Florida phosphate rock Index. décimale : 622 Industrie minière Résumé : Phosphate flotation has been used by industry for more than a half century but still faces many technical challenges. Such challenges include not only the selection of the chemical reagents but the characteristics of the feed itself. This paper deals with the investigation of feed characteristics and how these characteristics affect the flotation separation efficiency of feed material from a selected phosphate operation. Specifically why some feed, from the same mine, is efficiently separated with high recovery (good feed) while other feed is more difficult to separate (bad feed). The study was conducted using both traditional analytical techniques and more advanced techniques such as X-ray microtomography. The results reveal that the bad feed was highly porous, coarser in size, and, most significantly, exhibits a lower degree of liberation. Such bad feed was inefficiently separated by fatty acid flotation and improved recovery would require controlled grinding in order to improve the extent of liberation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750800188X

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Surface chemistry features in the flotation of KCl / Qinbo Cao in Minerals engineering, Vol. 23 N° 5 (Avril 2010)  

Public ISBD [article]  inMinerals engineering > Vol. 23 N° 5 (Avril 2010) . - pp. 365–373 Titre : Surface chemistry features in the flotation of KCl Type de document : texte imprimé Auteurs : Qinbo Cao, Auteur ; Hao Du, Auteur ; Jan D. Miller, Auteur Année de publication : 2011 Article en page(s) : pp. 365–373 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : KCl flotation Contact angle Adsorption Molecular dynamics simulation Résumé : Despite the successful industrial practice to recover KCl by flotation, the adsorption state of collectors at KCl salt surfaces is still not fully understood. In this paper, the flotation behavior of KCl and NaCl using different collectors and captive bubble contact angle measurements at KCl and NaCl crystal surfaces in their saturated solutions are reported. The influence of collector concentration and collector structure is considered. The results show that both cationic and anionic collectors produce a hydrophobic state at the structure breaking KCl salt surface, with finite contact angle values of between 30° and 60°. In contrast, the contact angle at the structure making NaCl salt surface is zero at all collector concentrations, suggesting that no collector adsorption occurs, a supposition that is supported by results from molecular dynamics simulation (MDS). Further, it appears that the presence of surface defects such as edges and corners promote the adsorption of collectors at the KCl surface, and that the flotation is achieved by bubble attachment at the edges/corners of KCl particles with the formation of aeroflocs. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900288X [article] Surface chemistry features in the flotation of KCl [texte imprimé] / Qinbo Cao, Auteur ; Hao Du, Auteur ; Jan D. Miller, Auteur . - 2011 . - pp. 365–373. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 5 (Avril 2010) . - pp. 365–373 Mots-clés : KCl flotation Contact angle Adsorption Molecular dynamics simulation Résumé : Despite the successful industrial practice to recover KCl by flotation, the adsorption state of collectors at KCl salt surfaces is still not fully understood. In this paper, the flotation behavior of KCl and NaCl using different collectors and captive bubble contact angle measurements at KCl and NaCl crystal surfaces in their saturated solutions are reported. The influence of collector concentration and collector structure is considered. The results show that both cationic and anionic collectors produce a hydrophobic state at the structure breaking KCl salt surface, with finite contact angle values of between 30° and 60°. In contrast, the contact angle at the structure making NaCl salt surface is zero at all collector concentrations, suggesting that no collector adsorption occurs, a supposition that is supported by results from molecular dynamics simulation (MDS). Further, it appears that the presence of surface defects such as edges and corners promote the adsorption of collectors at the KCl surface, and that the flotation is achieved by bubble attachment at the edges/corners of KCl particles with the formation of aeroflocs. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900288X

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The effect of an external magnetic field on cationic flotation of quartz from magnetite / Mustafa Birinci in Minerals engineering, Vol. 23 N° 10 (Septembre 2010)  

Public ISBD [article]  inMinerals engineering > Vol. 23 N° 10 (Septembre 2010) . - pp. 813–818 Titre : The effect of an external magnetic field on cationic flotation of quartz from magnetite Type de document : texte imprimé Auteurs : Mustafa Birinci, Auteur ; Jan D. Miller, Auteur ; Musa Sarıkaya, Auteur Année de publication : 2011 Article en page(s) : pp. 813–818 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : External magnetic field Magnetic flotation Quartz Magnetite Résumé : In this study, the effect of an external magnetic field on cationic flotation of quartz from magnetite was investigated by using a magnetic micro-flotation column. For this purpose, a micro-flotation column jacketed with three coils was fabricated to create a funnel-shaped magnetic field. Both the theoretical magnetic field strengths and the magnetic forces were calculated. The results from flotation experiments with 6 × 10−5 M dodecylamine as collector using a binary mixture of quartz and magnetite as a feed material show that the separation efficiency increased from 0% without the magnetic field to 88% in the presence of the magnetic field. The significant enhancement in separation efficiency is evident. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000155X [article] The effect of an external magnetic field on cationic flotation of quartz from magnetite [texte imprimé] / Mustafa Birinci, Auteur ; Jan D. Miller, Auteur ; Musa Sarıkaya, Auteur . - 2011 . - pp. 813–818. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 10 (Septembre 2010) . - pp. 813–818 Mots-clés : External magnetic field Magnetic flotation Quartz Magnetite Résumé : In this study, the effect of an external magnetic field on cationic flotation of quartz from magnetite was investigated by using a magnetic micro-flotation column. For this purpose, a micro-flotation column jacketed with three coils was fabricated to create a funnel-shaped magnetic field. Both the theoretical magnetic field strengths and the magnetic forces were calculated. The results from flotation experiments with 6 × 10−5 M dodecylamine as collector using a binary mixture of quartz and magnetite as a feed material show that the separation efficiency increased from 0% without the magnetic field to 88% in the presence of the magnetic field. The significant enhancement in separation efficiency is evident. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000155X

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The interaction of thiourea and formamidine disulfide in the dissolution of gold in sulfuric acid solutions / Xiyun Yang in Minerals engineering, Vol. 23 N° 9 (Août 2010)  

Public ISBD [article]  inMinerals engineering > Vol. 23 N° 9 (Août 2010) . - pp. 698–704 Titre : The interaction of thiourea and formamidine disulfide in the dissolution of gold in sulfuric acid solutions Type de document : texte imprimé Auteurs : Xiyun Yang, Auteur ; Michael S. Moats, Auteur ; Jan D. Miller, Auteur Année de publication : 2011 Article en page(s) : pp. 698–704 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Leaching Oxidation Redox reaction Résumé : The mechanism of gold dissolution in acidic thiourea (Tu) solutions was investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV). CV over the potential range of −0.3 to 0.75 V vs. SCE shows peaks for the Tu/FDS (formamidine disulfide) and View the MathML source redox reactions. An oxidation peak associated with gold dissolution occurs at ϕ ⩾ 0.36 V vs. SCE. This peak is often not observed in the first scan and its presence and magnitude are sensitive to the positive sweep potential limit of the first scan. FDS addition to the solution or adsorbed on the electrode has a strong catalytic effect and makes gold dissolution peak shift to lower potential during the first scan. This catalytic effect is identical to that exerted by scanning to higher potential. Tu/FDS ratio has a significant effect on thiourea stability, and it should be about 10:1 for the minimum thiourea decomposition and maximum gold dissolution rate. EIS results at 0.5−0.7 V vs. SCE with only Tu initially present in solution reveal a high-frequency capacitive loop associated with double layer charging, a medium-frequency inductive loop associated with FDS adsorption, and a low-frequency capacitive loop related to Tu oxidation. It appears that FDS adsorption on the gold surface activates the dissolution of gold and inhibits the oxidation of Tu. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001147 [article] The interaction of thiourea and formamidine disulfide in the dissolution of gold in sulfuric acid solutions [texte imprimé] / Xiyun Yang, Auteur ; Michael S. Moats, Auteur ; Jan D. Miller, Auteur . - 2011 . - pp. 698–704. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 9 (Août 2010) . - pp. 698–704 Mots-clés : Leaching Oxidation Redox reaction Résumé : The mechanism of gold dissolution in acidic thiourea (Tu) solutions was investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV). CV over the potential range of −0.3 to 0.75 V vs. SCE shows peaks for the Tu/FDS (formamidine disulfide) and View the MathML source redox reactions. An oxidation peak associated with gold dissolution occurs at ϕ ⩾ 0.36 V vs. SCE. This peak is often not observed in the first scan and its presence and magnitude are sensitive to the positive sweep potential limit of the first scan. FDS addition to the solution or adsorbed on the electrode has a strong catalytic effect and makes gold dissolution peak shift to lower potential during the first scan. This catalytic effect is identical to that exerted by scanning to higher potential. Tu/FDS ratio has a significant effect on thiourea stability, and it should be about 10:1 for the minimum thiourea decomposition and maximum gold dissolution rate. EIS results at 0.5−0.7 V vs. SCE with only Tu initially present in solution reveal a high-frequency capacitive loop associated with double layer charging, a medium-frequency inductive loop associated with FDS adsorption, and a low-frequency capacitive loop related to Tu oxidation. It appears that FDS adsorption on the gold surface activates the dissolution of gold and inhibits the oxidation of Tu. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001147

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