Dépouillements

Low grade ores – smelt, leach or concentrate? / T. Norgate in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 65-73 Titre : Low grade ores – smelt, leach or concentrate? Type de document : texte imprimé Auteurs : T. Norgate, Auteur ; S. Jahanshahi, Auteur Article en page(s) : pp. 65-73 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Hydrometallurgy  Leaching  Pyrometallurgy  Environmental  Extractive  metallurgy Index. décimale : 622 Industrie minière Résumé : Metallic ore grades are falling globally as the higher grade reserves are exploited first and are progressively depleted. At the same time, the demand for primary metals extracted from these ores is expected to increase, despite increased levels of dematerialisation and recycling. Sustainability concerns have highlighted the need to meet these demands while at the same time minimising resource consumption and environmental emissions. A study was therefore undertaken using life cycle assessment methodology to examine various alternative processing routes for extracting metal from low grade ores (down to 0.1% metal), particularly those of copper and nickel, in terms of their life cycle-based energy consumption (embodied energy) and greenhouse gas emissions. The processing routes examined included conventional concentrating and smelting, direct ore smelting, heap leaching, pressure leaching and in situ leaching. This paper presents the results of this study. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Low grade ores – smelt, leach or concentrate? [texte imprimé] / T. Norgate, Auteur ; S. Jahanshahi, Auteur . - pp. 65-73. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 65-73 Mots-clés : Hydrometallurgy  Leaching  Pyrometallurgy  Environmental  Extractive  metallurgy Index. décimale : 622 Industrie minière Résumé : Metallic ore grades are falling globally as the higher grade reserves are exploited first and are progressively depleted. At the same time, the demand for primary metals extracted from these ores is expected to increase, despite increased levels of dematerialisation and recycling. Sustainability concerns have highlighted the need to meet these demands while at the same time minimising resource consumption and environmental emissions. A study was therefore undertaken using life cycle assessment methodology to examine various alternative processing routes for extracting metal from low grade ores (down to 0.1% metal), particularly those of copper and nickel, in terms of their life cycle-based energy consumption (embodied energy) and greenhouse gas emissions. The processing routes examined included conventional concentrating and smelting, direct ore smelting, heap leaching, pressure leaching and in situ leaching. This paper presents the results of this study. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

Density based separations in the Reflux Classifier with an air–sand dense–medium and vibration / S. A. Macpherson in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 74-82 Titre : Density based separations in the Reflux Classifier with an air–sand dense–medium and vibration Type de document : texte imprimé Auteurs : S. A. Macpherson, Auteur ; S. M. Iveson, Auteur ; K. P. Galvin, Auteur Article en page(s) : pp. 74-82 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Dense  medium  separation  Gravity  concentration  Coal Index. décimale : 622 Industrie minière Résumé : The Reflux Classifier is a device consisting of parallel inclined channels above a fluidized bed. Water-based versions of the system have been successfully employed in industry for gravity separation of −2 + 0.25 mm coal and mineral matter. In this study an air-fluidized system was investigated using a single 2 m long inclined channel with 100 mm wide channels and 20 mm perpendicular spacing. Sand (−355 + 125 micron) was used as a dense–medium and vibration at two distinct levels was used to improve fluidization stability. Tracer particles of −6.35 + 1.00 mm nominal diameter and 1300 to 2400 kg/m3 density were used to study the effects of the vibration energy and vibration direction on the separation efficiency. The device was able to separate coal particles from a maximum of 8 mm down to 1 mm on the basis of density; hence this method has potential for industrial application. Results were analysed using a simple 2-parameter dispersion–convection model. Dense particles had negative slip velocities, low-density particles had positive slip velocities and the slip velocities were proportional to particle diameter. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Density based separations in the Reflux Classifier with an air–sand dense–medium and vibration [texte imprimé] / S. A. Macpherson, Auteur ; S. M. Iveson, Auteur ; K. P. Galvin, Auteur . - pp. 74-82. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 74-82 Mots-clés : Dense  medium  separation  Gravity  concentration  Coal Index. décimale : 622 Industrie minière Résumé : The Reflux Classifier is a device consisting of parallel inclined channels above a fluidized bed. Water-based versions of the system have been successfully employed in industry for gravity separation of −2 + 0.25 mm coal and mineral matter. In this study an air-fluidized system was investigated using a single 2 m long inclined channel with 100 mm wide channels and 20 mm perpendicular spacing. Sand (−355 + 125 micron) was used as a dense–medium and vibration at two distinct levels was used to improve fluidization stability. Tracer particles of −6.35 + 1.00 mm nominal diameter and 1300 to 2400 kg/m3 density were used to study the effects of the vibration energy and vibration direction on the separation efficiency. The device was able to separate coal particles from a maximum of 8 mm down to 1 mm on the basis of density; hence this method has potential for industrial application. Results were analysed using a simple 2-parameter dispersion–convection model. Dense particles had negative slip velocities, low-density particles had positive slip velocities and the slip velocities were proportional to particle diameter. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

Modeling of bubble surface area flux in an industrial rougher column using artificial neural network and statistical techniques / M. Massinaei in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 83-90 Titre : Modeling of bubble surface area flux in an industrial rougher column using artificial neural network and statistical techniques Type de document : texte imprimé Auteurs : M. Massinaei, Auteur ; R. Doostmohammadi, Auteur Article en page(s) : pp. 83-90 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  machines  Modeling  Neural  networks Index. décimale : 622 Industrie minière Résumé : Previous studies in mechanical and column flotation cells have shown that bubble surface area flux (Sb) is an appropriate indicator of gas dispersion in a flotation cell which has a relatively strong correlation with flotation rate constant. In the present investigation, based on extensive tests conducted in an industrial Metso Minerals CISA flotation column (4 m in diameter and 12 m in height) in a rougher circuit, Sb as a function of the most significant operating variables which affect gas dispersion in a flotation column (i.e. superficial gas velocity, slurry density (solids%) and frother dosage/type) was modeled using artificial neural network (ANN) and statistical (non-linear regression) techniques. The models were developed taking into consideration a data set consisting of 82 experimental tests conducted in an industrial rougher column (at a copper concentrator in Iran) operating under a variety of experimental conditions. This paper outlines the development of the models and validation using a number of randomly selected datasets. Limitations of the present models are discussed and comments and recommendations on further investigations are given. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Modeling of bubble surface area flux in an industrial rougher column using artificial neural network and statistical techniques [texte imprimé] / M. Massinaei, Auteur ; R. Doostmohammadi, Auteur . - pp. 83-90. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 83-90 Mots-clés : Froth  flotation  Flotation  machines  Modeling  Neural  networks Index. décimale : 622 Industrie minière Résumé : Previous studies in mechanical and column flotation cells have shown that bubble surface area flux (Sb) is an appropriate indicator of gas dispersion in a flotation cell which has a relatively strong correlation with flotation rate constant. In the present investigation, based on extensive tests conducted in an industrial Metso Minerals CISA flotation column (4 m in diameter and 12 m in height) in a rougher circuit, Sb as a function of the most significant operating variables which affect gas dispersion in a flotation column (i.e. superficial gas velocity, slurry density (solids%) and frother dosage/type) was modeled using artificial neural network (ANN) and statistical (non-linear regression) techniques. The models were developed taking into consideration a data set consisting of 82 experimental tests conducted in an industrial rougher column (at a copper concentrator in Iran) operating under a variety of experimental conditions. This paper outlines the development of the models and validation using a number of randomly selected datasets. Limitations of the present models are discussed and comments and recommendations on further investigations are given. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

The use of collectors mixture in the reverse cationic flotation of magnetite ore / L. O. Filippov in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 91-98 Titre : The use of collectors mixture in the reverse cationic flotation of magnetite ore : the role of Fe-bearing silicates Type de document : texte imprimé Auteurs : L. O. Filippov, Auteur ; I. V. Filippova, Auteur ; V. V. Severov, Auteur Article en page(s) : pp. 91-98 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Iron  ores  Amphiboles  Reverse  flotation  Zeta-potential  Etheramines Index. décimale : 622 Industrie minière Résumé : The paper describes effective reagent combinations for removal of silicates by reverse cationic flotation from magnetic concentrate in magnetite ores processing. This work is based on a hypothesis that a further development in reverse cationic flotation of iron ores implies, a more detailed consideration of the nature of the Fe-bearing gangue minerals. Thus, the choice of reagent regime has been determined by the similar physicochemical properties of iron oxides and silicates such as amphiboles due to inclusion of iron into their crystal lattice. Zeta-potential studies of Fe-oxides, quartz and Fe-bearing amphibole samples have shown that amines of different molecular structure are equally well adsorbed both on the surface of Fe-oxides and on the surface of silicates within рН range of 4–10. Flotation studies of quartz and Fe-bearing amphibole samples have revealed that the use of starch as a depressant of Fe-oxides has a hydrophilic effect on the surface of Fe-bearing silicates and significantly decreases their flotation by ether amines. Flotation of these minerals is not possible by primary monoamines in the presence of starch due to the adsorption layer formation. The experimentally selected mixtures of ether amines with primary monoamines or with alcohols provide formation of a hydrophobic adsorption layer on the surface of amphiboles and magnetite–silicate aggregates, even in the presence of starch in the system. A total hydrophobic effect is sufficient for an effective flotation of the entire silicate complex and producing of magnetite concentrates with SiO2 content <1.0% and Fe content up to 70.3% from magnetic concentrate with SiO2 content not, vert, similar3%. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] The use of collectors mixture in the reverse cationic flotation of magnetite ore : the role of Fe-bearing silicates [texte imprimé] / L. O. Filippov, Auteur ; I. V. Filippova, Auteur ; V. V. Severov, Auteur . - pp. 91-98. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 91-98 Mots-clés : Iron  ores  Amphiboles  Reverse  flotation  Zeta-potential  Etheramines Index. décimale : 622 Industrie minière Résumé : The paper describes effective reagent combinations for removal of silicates by reverse cationic flotation from magnetic concentrate in magnetite ores processing. This work is based on a hypothesis that a further development in reverse cationic flotation of iron ores implies, a more detailed consideration of the nature of the Fe-bearing gangue minerals. Thus, the choice of reagent regime has been determined by the similar physicochemical properties of iron oxides and silicates such as amphiboles due to inclusion of iron into their crystal lattice. Zeta-potential studies of Fe-oxides, quartz and Fe-bearing amphibole samples have shown that amines of different molecular structure are equally well adsorbed both on the surface of Fe-oxides and on the surface of silicates within рН range of 4–10. Flotation studies of quartz and Fe-bearing amphibole samples have revealed that the use of starch as a depressant of Fe-oxides has a hydrophilic effect on the surface of Fe-bearing silicates and significantly decreases their flotation by ether amines. Flotation of these minerals is not possible by primary monoamines in the presence of starch due to the adsorption layer formation. The experimentally selected mixtures of ether amines with primary monoamines or with alcohols provide formation of a hydrophobic adsorption layer on the surface of amphiboles and magnetite–silicate aggregates, even in the presence of starch in the system. A total hydrophobic effect is sufficient for an effective flotation of the entire silicate complex and producing of magnetite concentrates with SiO2 content <1.0% and Fe content up to 70.3% from magnetic concentrate with SiO2 content not, vert, similar3%. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

New collectors for the flotation of unactivated marmatite / Run-qing Liu in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 99-103 Titre : New collectors for the flotation of unactivated marmatite Type de document : texte imprimé Auteurs : Run-qing Liu, Auteur ; Wei Sun, Auteur ; Yue-hua Hu, Auteur Article en page(s) : pp. 99-103 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Sulfide  ores  Froth  flotation  Flotation  collectors Index. décimale : 622 Industrie minière Résumé : Three thiophenol collectors were tested for the flotation of marmatite without activation by copper sulfate. Flotation tests showed that marmatite flotation increased according to the following order: 2-fluoro thiophenol < 2-hydroxy thiophenol < 2-amino thiophenol. All these thiophenols exhibited a better flotation property for marmatite than butyl xanthate. Infrared spectra indicated that 2-amino thiophenol and 2-hydroxy thiophenol chemically adsorbed onto the surface of marmatite. 2-Fluoro thiophenol adsorbed physically onto the surface of marmatite. Quantum chemical calculations indicated that the energy of the highest occupied molecular orbital (HOMO) for 2-amino thiophenol was the highest among the tested collectors and we thus determined that its collecting ability should be the strongest. This agreed with the experimentally determined flotation results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] New collectors for the flotation of unactivated marmatite [texte imprimé] / Run-qing Liu, Auteur ; Wei Sun, Auteur ; Yue-hua Hu, Auteur . - pp. 99-103. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 99-103 Mots-clés : Sulfide  ores  Froth  flotation  Flotation  collectors Index. décimale : 622 Industrie minière Résumé : Three thiophenol collectors were tested for the flotation of marmatite without activation by copper sulfate. Flotation tests showed that marmatite flotation increased according to the following order: 2-fluoro thiophenol < 2-hydroxy thiophenol < 2-amino thiophenol. All these thiophenols exhibited a better flotation property for marmatite than butyl xanthate. Infrared spectra indicated that 2-amino thiophenol and 2-hydroxy thiophenol chemically adsorbed onto the surface of marmatite. 2-Fluoro thiophenol adsorbed physically onto the surface of marmatite. Quantum chemical calculations indicated that the energy of the highest occupied molecular orbital (HOMO) for 2-amino thiophenol was the highest among the tested collectors and we thus determined that its collecting ability should be the strongest. This agreed with the experimentally determined flotation results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

Possible role of hydrogen sulphide gas in self-heating of pyrrhotite-rich materials / Stéphanie Somot in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 104-110 Titre : Possible role of hydrogen sulphide gas in self-heating of pyrrhotite-rich materials Type de document : texte imprimé Auteurs : Stéphanie Somot, Auteur ; James A. Finch, Auteur Article en page(s) : pp. 104-110 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Environmental  Sulphide  ores  Self-heating  Hydrogen  sulphide  Non-ferrous  metallic  ores  Tailings  Oxidation  Reduction Index. décimale : 622 Industrie minière Résumé : Self-heating of sulphides poses safety, environmental and economic concerns to the mining and metallurgical industries, especially when sulphide ores or concentrates have to be stored or transported. The first target of this investigation is the self-heating of pyrrhotite (Po), the most commonly suspected mineral to trigger the phenomenon because of its fast oxidation in moist air. Following a standard experimental protocol, self-heating was assessed on samples of Po mixed with sand as an inert material. With increasing Po content, self-heating rates progressively increased but the samples visually appeared less and less oxidized. A high Po content, it was hypothesized, may give a more reducing environment favouring formation of hydrogen sulphide (H2S). The presence of this gas could be significant for self-heating for several reasons which are discussed. The hypothesis was tested by including copper pieces to detect the gas by forming copper sulphide, and adding copper sulphate in excess which suppressed self-heating, apparently by reacting with and removing the gas. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Possible role of hydrogen sulphide gas in self-heating of pyrrhotite-rich materials [texte imprimé] / Stéphanie Somot, Auteur ; James A. Finch, Auteur . - pp. 104-110. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 104-110 Mots-clés : Environmental  Sulphide  ores  Self-heating  Hydrogen  sulphide  Non-ferrous  metallic  ores  Tailings  Oxidation  Reduction Index. décimale : 622 Industrie minière Résumé : Self-heating of sulphides poses safety, environmental and economic concerns to the mining and metallurgical industries, especially when sulphide ores or concentrates have to be stored or transported. The first target of this investigation is the self-heating of pyrrhotite (Po), the most commonly suspected mineral to trigger the phenomenon because of its fast oxidation in moist air. Following a standard experimental protocol, self-heating was assessed on samples of Po mixed with sand as an inert material. With increasing Po content, self-heating rates progressively increased but the samples visually appeared less and less oxidized. A high Po content, it was hypothesized, may give a more reducing environment favouring formation of hydrogen sulphide (H2S). The presence of this gas could be significant for self-heating for several reasons which are discussed. The hypothesis was tested by including copper pieces to detect the gas by forming copper sulphide, and adding copper sulphate in excess which suppressed self-heating, apparently by reacting with and removing the gas. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

Packing of particles on the surface of bubbles / G. Bournival in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 111-116 Titre : Packing of particles on the surface of bubbles Type de document : texte imprimé Auteurs : G. Bournival, Auteur ; S. Ata, Auteur Article en page(s) : pp. 111-116 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Mineral  processing  Froth  flotation  Flotation  froths  Particle  size Index. décimale : 622 Industrie minière Résumé : In this paper, geometrical packing models were derived to determine the coverage of particles on an air bubble. Nearly spherical glass beads of two size fractions and galena particles were used in the study. The coverage of air bubbles by glass beads was carried out in the concentration range 2.74 × 10−5–1.65 × 10−3 mM of CTAB. The results indicated that coverage at all concentrations could be approximated with a hexagonal model with monodispersed particles using the value of d[4,3]. This could be done with a relative deviation of the packing factor within 15%. The coverage of an air bubble by galena particles was carried out in a collectorless environment. The best models were found to be a hexagonal or square cell using the value of d[1,0]. Experimental observations on particle packing are given and implications for the froth phase of flotation are discussed. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Packing of particles on the surface of bubbles [texte imprimé] / G. Bournival, Auteur ; S. Ata, Auteur . - pp. 111-116. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 111-116 Mots-clés : Mineral  processing  Froth  flotation  Flotation  froths  Particle  size Index. décimale : 622 Industrie minière Résumé : In this paper, geometrical packing models were derived to determine the coverage of particles on an air bubble. Nearly spherical glass beads of two size fractions and galena particles were used in the study. The coverage of air bubbles by glass beads was carried out in the concentration range 2.74 × 10−5–1.65 × 10−3 mM of CTAB. The results indicated that coverage at all concentrations could be approximated with a hexagonal model with monodispersed particles using the value of d[4,3]. This could be done with a relative deviation of the packing factor within 15%. The coverage of an air bubble by galena particles was carried out in a collectorless environment. The best models were found to be a hexagonal or square cell using the value of d[1,0]. Experimental observations on particle packing are given and implications for the froth phase of flotation are discussed. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

Hierarchical hybrid fuzzy strategy for column flotation control / Felipe Núñez in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 117-124 Titre : Hierarchical hybrid fuzzy strategy for column flotation control Type de document : texte imprimé Auteurs : Felipe Núñez, Auteur ; Luis Tapia, Auteur ; Aldo Cipriano, Auteur Article en page(s) : pp. 117-124 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Column  flotation  Hierarchical  control  Supervisory  control  Expert  systems  Fuzzy  control Index. décimale : 622 Industrie minière Résumé : Column flotation is widely used in the concentration of low grade ores. Often column flotation concentrate is the final product of a very complex circuit, and therefore control of the metallurgical performance has direct impact in the plant performance. Several control schemes has been implemented for the stabilization of column flotation process, including decentralized control, model predictive control and fuzzy approaches, which attempt to control froth depth, water bias and air holdup. At the same time many efforts have been oriented to improve process instrumentation, with the aim of providing better measurements for control purposes. Instrumentation improvements have made feasible the design of strategies focused on recovery and concentrate grade control. In this work we present the design and implementation of a new advanced controller for column flotation process. The controller was implemented in a 10 columns cleaning stage following a hierarchical scheme with two control levels: an improving level with the aim of metallurgical performance control of the whole process, and a stabilizing level in charge of the distribution of control actions in each column. The controller design was made based on a hybrid scheme with three different operation scenarios, defined by a recovery–concentrate grade domain partition. Results show that the controller is able to keep the process in the normal operation scenario 80% of the analyzed time; on the other hand, when the process was operated only with local control it achieved the normal operation scenario 43% of the analyzed time. Results also show that the controller is capable of increasing concentrate grade and recovery mean values, despite variations on feed grade; while reducing recovery and concentrate grade standard deviations. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Hierarchical hybrid fuzzy strategy for column flotation control [texte imprimé] / Felipe Núñez, Auteur ; Luis Tapia, Auteur ; Aldo Cipriano, Auteur . - pp. 117-124. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 117-124 Mots-clés : Column  flotation  Hierarchical  control  Supervisory  control  Expert  systems  Fuzzy  control Index. décimale : 622 Industrie minière Résumé : Column flotation is widely used in the concentration of low grade ores. Often column flotation concentrate is the final product of a very complex circuit, and therefore control of the metallurgical performance has direct impact in the plant performance. Several control schemes has been implemented for the stabilization of column flotation process, including decentralized control, model predictive control and fuzzy approaches, which attempt to control froth depth, water bias and air holdup. At the same time many efforts have been oriented to improve process instrumentation, with the aim of providing better measurements for control purposes. Instrumentation improvements have made feasible the design of strategies focused on recovery and concentrate grade control. In this work we present the design and implementation of a new advanced controller for column flotation process. The controller was implemented in a 10 columns cleaning stage following a hierarchical scheme with two control levels: an improving level with the aim of metallurgical performance control of the whole process, and a stabilizing level in charge of the distribution of control actions in each column. The controller design was made based on a hybrid scheme with three different operation scenarios, defined by a recovery–concentrate grade domain partition. Results show that the controller is able to keep the process in the normal operation scenario 80% of the analyzed time; on the other hand, when the process was operated only with local control it achieved the normal operation scenario 43% of the analyzed time. Results also show that the controller is capable of increasing concentrate grade and recovery mean values, despite variations on feed grade; while reducing recovery and concentrate grade standard deviations. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

GAS holdup and RTD measurement in an industrial flotation cell / Juan Yianatos in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 125-130 Titre : GAS holdup and RTD measurement in an industrial flotation cell Type de document : texte imprimé Auteurs : Juan Yianatos, Auteur ; Felipe Contreras, Auteur ; Francisco Díaz, Auteur Article en page(s) : pp. 125-130 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Gas  RTD  Flotation  cell  Gas  holdup  Gas  dispersion  Radioactive  tracing Index. décimale : 622 Industrie minière Résumé : In this work, the measurement of the axial gas holdup profile and gas residence time distribution (RTD), in a 130 m3 self-aerated flotation cell, is presented. For this purpose, a radioactive tracer gas was activated in the Nuclear Reactor of the Chilean Commission of Nuclear Energy. The gas tracer, Freon 13B1, was injected as an impulse signal at the gas (air) inlet point, located at the top of the cell, from which the gas tracer circulates first through the rotor, where the bubble dispersion occurs, and then the gas becomes well distributed over the whole cross-sectional area before leaving the cell. The axial gas holdup profile was estimated from the transient gas concentration measurement at different depths inside the cell. From these experiments it was found that the air entering the cell was preferentially distributed in the upper half of the cell, while the gas entrainment into tailings was negligible. The mean gas holdup was 8.8%, and consequently the effective pulp volume of collection zone was 91.2%. The gas concentration on top of froth was recorded for RTD measurement of the gas leaving the cell. It was found that the mean gas residence time was around 42 s and the mixing condition for gas and pulp was similar. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] GAS holdup and RTD measurement in an industrial flotation cell [texte imprimé] / Juan Yianatos, Auteur ; Felipe Contreras, Auteur ; Francisco Díaz, Auteur . - pp. 125-130. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 125-130 Mots-clés : Gas  RTD  Flotation  cell  Gas  holdup  Gas  dispersion  Radioactive  tracing Index. décimale : 622 Industrie minière Résumé : In this work, the measurement of the axial gas holdup profile and gas residence time distribution (RTD), in a 130 m3 self-aerated flotation cell, is presented. For this purpose, a radioactive tracer gas was activated in the Nuclear Reactor of the Chilean Commission of Nuclear Energy. The gas tracer, Freon 13B1, was injected as an impulse signal at the gas (air) inlet point, located at the top of the cell, from which the gas tracer circulates first through the rotor, where the bubble dispersion occurs, and then the gas becomes well distributed over the whole cross-sectional area before leaving the cell. The axial gas holdup profile was estimated from the transient gas concentration measurement at different depths inside the cell. From these experiments it was found that the air entering the cell was preferentially distributed in the upper half of the cell, while the gas entrainment into tailings was negligible. The mean gas holdup was 8.8%, and consequently the effective pulp volume of collection zone was 91.2%. The gas concentration on top of froth was recorded for RTD measurement of the gas leaving the cell. It was found that the mean gas residence time was around 42 s and the mixing condition for gas and pulp was similar. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

Measurement of particle loading on bubbles in the flotation process / M. H. Moys in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 131-136 Titre : Measurement of particle loading on bubbles in the flotation process Type de document : texte imprimé Auteurs : M. H. Moys, Auteur ; J. Yianatos, Auteur ; J. Larenas, Auteur Article en page(s) : pp. 131-136 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Flotation  Forth  recovery  Bubble  load  Measurement Index. décimale : 622 Industrie minière Résumé : Methods for estimation or measurement of particle loading on bubbles in the flotation process are reviewed. The paper focuses on direct measurement methods developed under the direction of Moys at the University of the Witwatersrand and by Seaman and co-workers at the JKMRC, Brisbane, Australia. Deficiencies in both designs are identified and a new design which deals with all these deficiencies is proposed. A hydrodynamic model for this version is developed and tested in a water-only environment, then tested on the copper flotation plant at El Teniente. It was found that the new design had successfully dealt with prior method deficiencies and provided a very precise (relative standard deviation equal to 0.72%) measurement of the loading on the bubbles in five tests. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Measurement of particle loading on bubbles in the flotation process [texte imprimé] / M. H. Moys, Auteur ; J. Yianatos, Auteur ; J. Larenas, Auteur . - pp. 131-136. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 131-136 Mots-clés : Flotation  Forth  recovery  Bubble  load  Measurement Index. décimale : 622 Industrie minière Résumé : Methods for estimation or measurement of particle loading on bubbles in the flotation process are reviewed. The paper focuses on direct measurement methods developed under the direction of Moys at the University of the Witwatersrand and by Seaman and co-workers at the JKMRC, Brisbane, Australia. Deficiencies in both designs are identified and a new design which deals with all these deficiencies is proposed. A hydrodynamic model for this version is developed and tested in a water-only environment, then tested on the copper flotation plant at El Teniente. It was found that the new design had successfully dealt with prior method deficiencies and provided a very precise (relative standard deviation equal to 0.72%) measurement of the loading on the bubbles in five tests. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

Geometallurgical modelling of the Collahuasi flotation circuit / C. J. Suazo in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 137-142 Titre : Geometallurgical modelling of the Collahuasi flotation circuit Type de document : texte imprimé Auteurs : C. J. Suazo, Auteur ; W. Kracht, Auteur ; O. M. Alruiz, Auteur Article en page(s) : pp. 137-142 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Geometallurgy  Modelling  Flotation  kinetics Index. décimale : 622 Industrie minière Résumé : The flotation rate constant was modelled as a function of air dispersion properties and the complete feed particle size distribution by using the collision–attachment–detachment approach and introducing a parameter (Ф) which represents the inherent floatability of the ore. It was found that this parameter Ф is characteristic of the geometallurgical unit and does not depend on the main operating conditions. The parameter Ф is dimensionless and can be estimated either from laboratory testwork or directly from an industrial kinetics survey and can be used to predict industrial operation, provided that the other components of the model are evaluated under actual operation conditions. An empirical expression for the maximum achievable recovery – infinite time recovery – is also presented. The complete model, including flotation rate constant and infinite time recovery, was tested showing good correlation at both laboratory and industrial scale. At industrial scale the model was able to predict metallurgical results in a time frame of several weeks at Compañia Minera Doña Inés de Collahuasi SCM, showing an average relative error of less than 2%. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Geometallurgical modelling of the Collahuasi flotation circuit [texte imprimé] / C. J. Suazo, Auteur ; W. Kracht, Auteur ; O. M. Alruiz, Auteur . - pp. 137-142. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 137-142 Mots-clés : Geometallurgy  Modelling  Flotation  kinetics Index. décimale : 622 Industrie minière Résumé : The flotation rate constant was modelled as a function of air dispersion properties and the complete feed particle size distribution by using the collision–attachment–detachment approach and introducing a parameter (Ф) which represents the inherent floatability of the ore. It was found that this parameter Ф is characteristic of the geometallurgical unit and does not depend on the main operating conditions. The parameter Ф is dimensionless and can be estimated either from laboratory testwork or directly from an industrial kinetics survey and can be used to predict industrial operation, provided that the other components of the model are evaluated under actual operation conditions. An empirical expression for the maximum achievable recovery – infinite time recovery – is also presented. The complete model, including flotation rate constant and infinite time recovery, was tested showing good correlation at both laboratory and industrial scale. At industrial scale the model was able to predict metallurgical results in a time frame of several weeks at Compañia Minera Doña Inés de Collahuasi SCM, showing an average relative error of less than 2%. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

Thiosulphate leaching of gold in the presence of ethylenediaminetetraacetic acid (EDTA) / D. Feng in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 143-150 Titre : Thiosulphate leaching of gold in the presence of ethylenediaminetetraacetic acid (EDTA) Type de document : texte imprimé Auteurs : D. Feng, Auteur ; J. S. J. van Deventer, Auteur Article en page(s) : pp. 143-150 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Gold  ores  Sulphide  ores  Grinding  Leaching  Surface  modification Index. décimale : 622 Industrie minière Résumé : The addition of low levels of ethylenediaminetetraacetic acid (EDTA) in the ammoniacal thiosulphate gold leach system lowered the catalytic cupric/cuprous redox equilibrium potential, hence the mixed solution potential and reduced the consumption of thiosulphate. In the leaching of pure gold, gold dissolution was enhanced in the presence of EDTA at a relatively low concentration, but excessive EDTA decreased gold dissolution. Raman analysis of the leached gold foil indicated that the stabilisation of thiosulphate by EDTA decreased the formation of the passivation layers of elemental sulphur and copper sulphide at the gold surface. In the leaching of a sulphide ore, the leaching kinetics and overall extractions of gold and silver were enhanced substantially, while the consumption of ammonium thiosulphate was reduced from 9.63 kg/t to 3.85 kg/t in the presence of 2.0 mM EDTA after 24 h leaching. This beneficial effect became more pronounced at a higher EDTA concentration. The enhanced gold and silver extractions by EDTA were attributed to the increase in the dissolution of gold and silver bearing sulphides, the stabilisation of copper and thiosulphate in leach solutions, the prevention of leaching passivation and the decrease in the interference of foreign heavy metal ions. The use of EDTA in the ammoniacal thiosulphate leaching system makes it practical to achieve satisfactory gold extraction over extended periods of leaching under low reagent concentrations, where the consumption of thiosulphate is low. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Thiosulphate leaching of gold in the presence of ethylenediaminetetraacetic acid (EDTA) [texte imprimé] / D. Feng, Auteur ; J. S. J. van Deventer, Auteur . - pp. 143-150. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 143-150 Mots-clés : Gold  ores  Sulphide  ores  Grinding  Leaching  Surface  modification Index. décimale : 622 Industrie minière Résumé : The addition of low levels of ethylenediaminetetraacetic acid (EDTA) in the ammoniacal thiosulphate gold leach system lowered the catalytic cupric/cuprous redox equilibrium potential, hence the mixed solution potential and reduced the consumption of thiosulphate. In the leaching of pure gold, gold dissolution was enhanced in the presence of EDTA at a relatively low concentration, but excessive EDTA decreased gold dissolution. Raman analysis of the leached gold foil indicated that the stabilisation of thiosulphate by EDTA decreased the formation of the passivation layers of elemental sulphur and copper sulphide at the gold surface. In the leaching of a sulphide ore, the leaching kinetics and overall extractions of gold and silver were enhanced substantially, while the consumption of ammonium thiosulphate was reduced from 9.63 kg/t to 3.85 kg/t in the presence of 2.0 mM EDTA after 24 h leaching. This beneficial effect became more pronounced at a higher EDTA concentration. The enhanced gold and silver extractions by EDTA were attributed to the increase in the dissolution of gold and silver bearing sulphides, the stabilisation of copper and thiosulphate in leach solutions, the prevention of leaching passivation and the decrease in the interference of foreign heavy metal ions. The use of EDTA in the ammoniacal thiosulphate leaching system makes it practical to achieve satisfactory gold extraction over extended periods of leaching under low reagent concentrations, where the consumption of thiosulphate is low. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

Predicting the specific energy required for size reduction of relatively coarse feeds in conventional crushers and high pressure grinding rolls / S. Morrell in Minerals engineering, Vol. 23 N° 2 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 151-153 Titre : Predicting the specific energy required for size reduction of relatively coarse feeds in conventional crushers and high pressure grinding rolls Type de document : texte imprimé Auteurs : S. Morrell, Auteur Article en page(s) : pp. 151-153 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Comminution  Crushing Index. décimale : 622 Industrie minière Résumé : In a previous paper (Morrell, 2009. Predicting the overall specific energy requirement of crushing, high pressure grinding roll and tumbling mill circuits. Minerals Engineering 22 (6), 544–549), an approach was described to predict the specific energy of a range of tumbling mill and crushing/high pressure grinding rolls (HPGR) circuits. In the case of crushing and HPGR circuits, recently acquired data have enabled this approach to be extended to coarser particle size reduction situations. This is achieved through the use of a size-dependent hardness parameter. Crushing and HPGR conditions are described where the use of this parameter should improve the accuracy of specific energy predictions. A worked example is also given. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Predicting the specific energy required for size reduction of relatively coarse feeds in conventional crushers and high pressure grinding rolls [texte imprimé] / S. Morrell, Auteur . - pp. 151-153. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 2 (Janvier 2010) . - pp. 151-153 Mots-clés : Comminution  Crushing Index. décimale : 622 Industrie minière Résumé : In a previous paper (Morrell, 2009. Predicting the overall specific energy requirement of crushing, high pressure grinding roll and tumbling mill circuits. Minerals Engineering 22 (6), 544–549), an approach was described to predict the specific energy of a range of tumbling mill and crushing/high pressure grinding rolls (HPGR) circuits. In the case of crushing and HPGR circuits, recently acquired data have enabled this approach to be extended to coarser particle size reduction situations. This is achieved through the use of a size-dependent hardness parameter. Crushing and HPGR conditions are described where the use of this parameter should improve the accuracy of specific energy predictions. A worked example is also given. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

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