Dépouillements

Operating strategies to maximise gold recovery at telfer / X. Zheng in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1159–1166 Titre : Operating strategies to maximise gold recovery at telfer Type de document : texte imprimé Auteurs : X. Zheng, Auteur ; P. Manton, Auteur ; F. Burns, Auteur Année de publication : 2011 Article en page(s) : pp. 1159–1166 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Liberation  Gold Résumé : On average, the difference in recovery between copper and gold is 15% among the large scale copper/gold operations. At Telfer, a number of operating strategies have been implemented together with a sequential flotation circuit design to maximise gold recovery. The main operating strategies include targeting a primary grind size optimum for copper recovery, designing and operating the main flotation circuit as copper and pyrite sequential flotation, targeting a minimum saleable concentrate copper grade, allowing a portion of pyrite/gold recovered into the copper concentrate and leaching the pyrite concentrate to extract the gold. These operating strategies have lifted the recovery of both copper and gold above 90%. There are opportunities to further improve the metallurgical performance at Telfer, including a single stage of cleaning of the copper rougher concentrate, regrinding of the copper scavenger concentrate prior to cleaning and regrinding of the pyrite rougher concentrate followed by additional copper/gold flotation prior to pyrite leaching. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000701 [article] Operating strategies to maximise gold recovery at telfer [texte imprimé] / X. Zheng, Auteur ; P. Manton, Auteur ; F. Burns, Auteur . - 2011 . - pp. 1159–1166. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1159–1166 Mots-clés : Froth  flotation  Liberation  Gold Résumé : On average, the difference in recovery between copper and gold is 15% among the large scale copper/gold operations. At Telfer, a number of operating strategies have been implemented together with a sequential flotation circuit design to maximise gold recovery. The main operating strategies include targeting a primary grind size optimum for copper recovery, designing and operating the main flotation circuit as copper and pyrite sequential flotation, targeting a minimum saleable concentrate copper grade, allowing a portion of pyrite/gold recovered into the copper concentrate and leaching the pyrite concentrate to extract the gold. These operating strategies have lifted the recovery of both copper and gold above 90%. There are opportunities to further improve the metallurgical performance at Telfer, including a single stage of cleaning of the copper rougher concentrate, regrinding of the copper scavenger concentrate prior to cleaning and regrinding of the pyrite rougher concentrate followed by additional copper/gold flotation prior to pyrite leaching. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000701

Development and evaluation of an early removal process for the beneficiation of arsenic-bearing copper ores / W. J. Bruckard in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1167–1173 Titre : Development and evaluation of an early removal process for the beneficiation of arsenic-bearing copper ores Type de document : texte imprimé Auteurs : W. J. Bruckard, Auteur ; K.J. Davey, Auteur ; F.R.A. Jorgensen, Auteur Année de publication : 2011 Article en page(s) : pp. 1167–1173 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Arsenic  Copper  Controlled-potential  flotation  Roasting  Immobilization Résumé : In conventional flotation flowsheets for treating copper sulphide ores containing small but significant amounts of arsenic, the arsenic is generally concentrated with the copper in final concentrate. Often, a penalty can be imposed by the smelter processing the concentrate, based on the arsenic content. In some cases the arsenic level is such that the smelter will not treat or accept the concentrate. A new approach to address this issue is reported in this paper, which is becoming more significant as the quality of the copper ore bodies currently being mined diminishes. A new flowsheet, based on the early removal of arsenic at the concentrator, has been developed and tested at bench-scale. The proposed flowsheet comprises three key steps: firstly, separation of arsenic and copper minerals using controlled-potential flotation to produce a low-arsenic high-copper concentrate and a high-arsenic low-copper concentrate. The low-arsenic concentrate can be sold without incurring any penalty for arsenic content. In the second stage, the high-arsenic concentrate is subjected to a low temperature roasting, where the arsenic is selectively fumed off into a low-volume stream product. The calcine from the roaster is high in copper and sulphur and can still be smelted directly. In the final stage of the flowsheet, the arsenic in the fume product is immobilised in a low temperature ceramic such that safe disposal back into the ground is possible. The new early removal flowsheet has been sequentially tested in the laboratory at small scale. The technical and economic merits of the flowsheet compared with that of the conventional copper flotation flowsheet show that there is a net benefit. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000713 [article] Development and evaluation of an early removal process for the beneficiation of arsenic-bearing copper ores [texte imprimé] / W. J. Bruckard, Auteur ; K.J. Davey, Auteur ; F.R.A. Jorgensen, Auteur . - 2011 . - pp. 1167–1173. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1167–1173 Mots-clés : Arsenic  Copper  Controlled-potential  flotation  Roasting  Immobilization Résumé : In conventional flotation flowsheets for treating copper sulphide ores containing small but significant amounts of arsenic, the arsenic is generally concentrated with the copper in final concentrate. Often, a penalty can be imposed by the smelter processing the concentrate, based on the arsenic content. In some cases the arsenic level is such that the smelter will not treat or accept the concentrate. A new approach to address this issue is reported in this paper, which is becoming more significant as the quality of the copper ore bodies currently being mined diminishes. A new flowsheet, based on the early removal of arsenic at the concentrator, has been developed and tested at bench-scale. The proposed flowsheet comprises three key steps: firstly, separation of arsenic and copper minerals using controlled-potential flotation to produce a low-arsenic high-copper concentrate and a high-arsenic low-copper concentrate. The low-arsenic concentrate can be sold without incurring any penalty for arsenic content. In the second stage, the high-arsenic concentrate is subjected to a low temperature roasting, where the arsenic is selectively fumed off into a low-volume stream product. The calcine from the roaster is high in copper and sulphur and can still be smelted directly. In the final stage of the flowsheet, the arsenic in the fume product is immobilised in a low temperature ceramic such that safe disposal back into the ground is possible. The new early removal flowsheet has been sequentially tested in the laboratory at small scale. The technical and economic merits of the flowsheet compared with that of the conventional copper flotation flowsheet show that there is a net benefit. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000713

A new predictive model of lifter bar wear in mills / M. Rezaeizadeh in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1174–1181 Titre : A new predictive model of lifter bar wear in mills Type de document : texte imprimé Auteurs : M. Rezaeizadeh, Auteur ; M. Fooladi, Auteur ; M.S. Powell, Auteur Année de publication : 2011 Article en page(s) : pp. 1174–1181 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Mineral  processing  Comminution  Grinding  Particle  size Résumé : The cost of mill relining and the influence of the liner profiles on mill performance provide a strong motivation to improve liner selection. However, the capability to predict liner life and progressive profile is poorly developed in the industry. A new model has been developed to predict the rate of liner wear based on the main parameters affecting the wear process such as; ore type, relative velocity between the ore and the liners, liner hardness and friction conditions. The resultant model is capable of determining the wear as a function of mill operating and discharge conditions based on the variation of specific gravity of mill contents, geometrical characteristics of the mill and mill velocity. The results from this model are in good agreement with the measured data from the SAG mill at Sarcheshmeh Copper Complex, Iran. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001974 [article] A new predictive model of lifter bar wear in mills [texte imprimé] / M. Rezaeizadeh, Auteur ; M. Fooladi, Auteur ; M.S. Powell, Auteur . - 2011 . - pp. 1174–1181. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1174–1181 Mots-clés : Mineral  processing  Comminution  Grinding  Particle  size Résumé : The cost of mill relining and the influence of the liner profiles on mill performance provide a strong motivation to improve liner selection. However, the capability to predict liner life and progressive profile is poorly developed in the industry. A new model has been developed to predict the rate of liner wear based on the main parameters affecting the wear process such as; ore type, relative velocity between the ore and the liners, liner hardness and friction conditions. The resultant model is capable of determining the wear as a function of mill operating and discharge conditions based on the variation of specific gravity of mill contents, geometrical characteristics of the mill and mill velocity. The results from this model are in good agreement with the measured data from the SAG mill at Sarcheshmeh Copper Complex, Iran. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001974

Experimental observations of lifter parameters and mill operation on power draw and liner impact loading / M. Rezaeizadeh in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1182–1191 Titre : Experimental observations of lifter parameters and mill operation on power draw and liner impact loading Type de document : texte imprimé Auteurs : M. Rezaeizadeh, Auteur ; M. Fooladi, Auteur ; M.S. Powell, Auteur Année de publication : 2011 Article en page(s) : pp. 1182–1191 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Comminution  Grinding  Crushing  SAG  mill Résumé : In mineral processing the mill power plays a major role in the economics of the process and is a critical design criterion. The mill power is influenced by a range of parameters such as: charge and slurry filling, number and geometry of lifters, and mill speed. Deriving the optimum conditions of these parameters should lead to efficient mill operation. Additionally, the optimum utilization of the impact loads that are affected by charge and slurry filling, number of lifters, geometry of lifter and mill speed should result in increased milling efficiency. In this work the influence of these operating parameters were investigated using a laboratory experimental mill. It is found that the power, are affected by number of lifters, lifter height, mill charge and mill speed. Overall the results showed that increasing the mill velocity, number of lifters, and height of lifter and significantly decreasing the mill charge filling results in a higher impact value and impact frequency that may also increase overall efficiency. A simple linear regression relationship has been demonstrated for mill power as a function of lifter spacing (S/H) and mill speed. These parameters give an indication of the possible optimum mill operating conditions in an idealised condition. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001986 [article] Experimental observations of lifter parameters and mill operation on power draw and liner impact loading [texte imprimé] / M. Rezaeizadeh, Auteur ; M. Fooladi, Auteur ; M.S. Powell, Auteur . - 2011 . - pp. 1182–1191. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1182–1191 Mots-clés : Comminution  Grinding  Crushing  SAG  mill Résumé : In mineral processing the mill power plays a major role in the economics of the process and is a critical design criterion. The mill power is influenced by a range of parameters such as: charge and slurry filling, number and geometry of lifters, and mill speed. Deriving the optimum conditions of these parameters should lead to efficient mill operation. Additionally, the optimum utilization of the impact loads that are affected by charge and slurry filling, number of lifters, geometry of lifter and mill speed should result in increased milling efficiency. In this work the influence of these operating parameters were investigated using a laboratory experimental mill. It is found that the power, are affected by number of lifters, lifter height, mill charge and mill speed. Overall the results showed that increasing the mill velocity, number of lifters, and height of lifter and significantly decreasing the mill charge filling results in a higher impact value and impact frequency that may also increase overall efficiency. A simple linear regression relationship has been demonstrated for mill power as a function of lifter spacing (S/H) and mill speed. These parameters give an indication of the possible optimum mill operating conditions in an idealised condition. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001986

Selective depression of diaspore with waxy maize starch / Haipu Li in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1192–1197 Titre : Selective depression of diaspore with waxy maize starch Type de document : texte imprimé Auteurs : Haipu Li, Auteur ; Shasha Zhang, Auteur ; Hao Jiang, Auteur Année de publication : 2011 Article en page(s) : pp. 1192–1197 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Diasporic  bauxite  Reverse  flotation  Selective  depression  Waxy  maize  starch Résumé : Highly branched waxy maize starch (WMS) was used to separate diaspore from artificial mixtures of diaspore and kaolinite by microflotation using dodecylamine (DDA) as collector. It was found that WMS depressed the diaspore flotation while activated the kaolinite flotation more or less. The adsorption of WMS on diaspore was examined through adsorption test, zeta potential measurement, infrared spectroscopy, and atomic force microscopy. It is suggested that both chemical interaction and intermolecular hydrogen bonding by hydroxyl groups of starch with surface Al–OH moieties occurred in the adsorption. Results obtained from the adsorption of DDA and WMS on diaspore showed that starch virtually enhanced the DDA adsorption. The depressant action of WMS can be rationalized primarily by the formation of hydrophilic adsorption layer enveloping the surface of diaspore and covering the collector. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002013 [article] Selective depression of diaspore with waxy maize starch [texte imprimé] / Haipu Li, Auteur ; Shasha Zhang, Auteur ; Hao Jiang, Auteur . - 2011 . - pp. 1192–1197. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1192–1197 Mots-clés : Diasporic  bauxite  Reverse  flotation  Selective  depression  Waxy  maize  starch Résumé : Highly branched waxy maize starch (WMS) was used to separate diaspore from artificial mixtures of diaspore and kaolinite by microflotation using dodecylamine (DDA) as collector. It was found that WMS depressed the diaspore flotation while activated the kaolinite flotation more or less. The adsorption of WMS on diaspore was examined through adsorption test, zeta potential measurement, infrared spectroscopy, and atomic force microscopy. It is suggested that both chemical interaction and intermolecular hydrogen bonding by hydroxyl groups of starch with surface Al–OH moieties occurred in the adsorption. Results obtained from the adsorption of DDA and WMS on diaspore showed that starch virtually enhanced the DDA adsorption. The depressant action of WMS can be rationalized primarily by the formation of hydrophilic adsorption layer enveloping the surface of diaspore and covering the collector. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002013

Flotation of copper sulphides assisted by high intensity conditioning (HIC) and concentrate recirculation / Erico Tabosa in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1198–1206 Titre : Flotation of copper sulphides assisted by high intensity conditioning (HIC) and concentrate recirculation Type de document : texte imprimé Auteurs : Erico Tabosa, Auteur ; Jorge Rubio, Auteur Année de publication : 2011 Article en page(s) : pp. 1198–1206 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  High  intensity  conditioning  Concentrate  recycling  Copper  sulphide  fines Résumé : This paper describes the effect of the partial concentrate (rougher floated product) recirculation to rougher flotation feed, here named concentrate recirculation flotation – CRF, at laboratory scale. The main parameters used to evaluate this alternative approach were flotation rate and recovery of fine (“F” 40–13 μm) and ultrafine (“UF” <13 μm) copper sulphide particles. Also, the comparative effect of high intensity conditioning (HIC), as a pre-flotation stage for the rougher flotation, was studied alone or combined with CRF. Results were evaluated through separation parameters, grade-recovery and flotation rates, especially in the fine and ultrafine fractions, a very old problem of processing by flotation. Results showed that the floated concentrate recirculation enhanced the metallurgical recovery, grade and rate flotation of copper sulphides. The best results were obtained with concentrate recirculation flotation combined with high intensity conditioning (CRF–HIC). The kinetics rate values doubled, the Cu recovery increased 17%, the Cu grade increased 3.6% and the flotation rates were 2.4 times faster. These were accompanied by improving 32% the “true” flotation values equivalent to 2.4 times lower the amount of entrained copper particles. These results were explained and proved to proceed by particle aggregation (among others) occurring after HIC, assisted by the recycled floatable particles. This “artificial” increase in valuable mineral grade (by the CR) resulted in higher collision probability between hydrophobic particles acting as “seeds” or “carrier”. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002037 [article] Flotation of copper sulphides assisted by high intensity conditioning (HIC) and concentrate recirculation [texte imprimé] / Erico Tabosa, Auteur ; Jorge Rubio, Auteur . - 2011 . - pp. 1198–1206. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1198–1206 Mots-clés : Flotation  High  intensity  conditioning  Concentrate  recycling  Copper  sulphide  fines Résumé : This paper describes the effect of the partial concentrate (rougher floated product) recirculation to rougher flotation feed, here named concentrate recirculation flotation – CRF, at laboratory scale. The main parameters used to evaluate this alternative approach were flotation rate and recovery of fine (“F” 40–13 μm) and ultrafine (“UF” <13 μm) copper sulphide particles. Also, the comparative effect of high intensity conditioning (HIC), as a pre-flotation stage for the rougher flotation, was studied alone or combined with CRF. Results were evaluated through separation parameters, grade-recovery and flotation rates, especially in the fine and ultrafine fractions, a very old problem of processing by flotation. Results showed that the floated concentrate recirculation enhanced the metallurgical recovery, grade and rate flotation of copper sulphides. The best results were obtained with concentrate recirculation flotation combined with high intensity conditioning (CRF–HIC). The kinetics rate values doubled, the Cu recovery increased 17%, the Cu grade increased 3.6% and the flotation rates were 2.4 times faster. These were accompanied by improving 32% the “true” flotation values equivalent to 2.4 times lower the amount of entrained copper particles. These results were explained and proved to proceed by particle aggregation (among others) occurring after HIC, assisted by the recycled floatable particles. This “artificial” increase in valuable mineral grade (by the CR) resulted in higher collision probability between hydrophobic particles acting as “seeds” or “carrier”. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002037

Effect of mechano-chemical activation on bioleaching of Indian Ocean nodules by a fungus / K.D. Mehta in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1207–1212 Titre : Effect of mechano-chemical activation on bioleaching of Indian Ocean nodules by a fungus Type de document : texte imprimé Auteurs : K.D. Mehta, Auteur ; Chitrangada Das, Auteur ; Kumar, Rakesh, Auteur Année de publication : 2011 Article en page(s) : pp. 1207–1212 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Mechano-chemical  activation  Ocean  nodules  Bioleaching  Aspergillus  niger Résumé : The effect of mechano-chemical activation of Indian sea nodules, while recording the zeta potential, particle size distribution and surface area, on the bio-dissolution of metals by Aspergillus niger has been investigated. Activation is a term used to indicate what takes place when increasing grinding time does not result in significant change in particle size but rather results in the accumulation of energy that may lead to the development of lattice defects within the particles that can aid biological attack. It was observed that the mechano-chemical activation improved the bio-dissolution of metals such as copper, nickel and cobalt from the sea nodules at initial pH in the range 4.0–5.0. With 10 min milling of particles of ⩽75 μm size, 86% material was reduced to ⩽10 μm size with a change in zeta potential from −18 to −34 mV. Above 95% copper, nickel and cobalt each was leached out in 15 days time from the nodules activated for 10 min at 5% (w/v) PD and 35 °C temperature with initial pH of 4.5; the biorecovery being almost similar when the material was activated for 30 min. In the case of nodules without activation, ⩾89% metal bioleaching was achieved in 25 days time at an initial pH of 4.5 under this condition. The mechano-chemical activation of sea nodules has thus influenced the bio-dissolution process, while providing a wider pH range available for processing of nodules with the involvement of organic acids such as oxalic and citric generated from the fungus. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002074 [article] Effect of mechano-chemical activation on bioleaching of Indian Ocean nodules by a fungus [texte imprimé] / K.D. Mehta, Auteur ; Chitrangada Das, Auteur ; Kumar, Rakesh, Auteur . - 2011 . - pp. 1207–1212. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1207–1212 Mots-clés : Mechano-chemical  activation  Ocean  nodules  Bioleaching  Aspergillus  niger Résumé : The effect of mechano-chemical activation of Indian sea nodules, while recording the zeta potential, particle size distribution and surface area, on the bio-dissolution of metals by Aspergillus niger has been investigated. Activation is a term used to indicate what takes place when increasing grinding time does not result in significant change in particle size but rather results in the accumulation of energy that may lead to the development of lattice defects within the particles that can aid biological attack. It was observed that the mechano-chemical activation improved the bio-dissolution of metals such as copper, nickel and cobalt from the sea nodules at initial pH in the range 4.0–5.0. With 10 min milling of particles of ⩽75 μm size, 86% material was reduced to ⩽10 μm size with a change in zeta potential from −18 to −34 mV. Above 95% copper, nickel and cobalt each was leached out in 15 days time from the nodules activated for 10 min at 5% (w/v) PD and 35 °C temperature with initial pH of 4.5; the biorecovery being almost similar when the material was activated for 30 min. In the case of nodules without activation, ⩾89% metal bioleaching was achieved in 25 days time at an initial pH of 4.5 under this condition. The mechano-chemical activation of sea nodules has thus influenced the bio-dissolution process, while providing a wider pH range available for processing of nodules with the involvement of organic acids such as oxalic and citric generated from the fungus. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002074

Spreadsheet-based modeling of liner wear impact on charge motion in tumbling mills / M. Yahyaei in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1213–1219 Titre : Spreadsheet-based modeling of liner wear impact on charge motion in tumbling mills Type de document : texte imprimé Auteurs : M. Yahyaei, Auteur ; S. Banisi, Auteur Année de publication : 2011 Article en page(s) : pp. 1213–1219 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Comminution  SAG  milling  Modeling Résumé : Grinding remains the major constituent of the total cost of processing minerals in most applications. Charge motion is one of the key parameters affecting grinding efficiency and mill power draw. Although there have been numerous investigations on the effect of liner design on charge motion, the effect of charge profile due to liner wear during mill operation along the mill length has not received much attention. In this research, Powell’s analytical approach to calculate the charge trajectory with respect to the liner profile was used to develop a software based on Microsoft Excel© . As a case study, the liner wear profile of the Sarcheshmeh copper complex SAG mill was used to model the liner wear rate and calculate the changes of lifter face angle and lifter height during mill operation. Results were then used to determine charge motion in the SAG mill at any given operation time. The results indicated that after 4000 h of operation the lifters face angle increased from 14° to 47.1° and the height of lifters decreased from 15.2 to 5.8 cm. Modeling charge motion in the mill after 3000 h of operation showed 34° difference between the maximum and minimum of angles of impact along the mill length due to the nonuniform wear profile. It was also found that the variation in the pattern of the charge motion depends on the mill working hours and the distance of the desired point from the feed end. It was determined that the ratio of spacing to the height of lifters (S/H) plays an important role in the grinding efficiency and throughput. After 4000 h of operation, S/H ratio of the Sarcheshmeh SAG mill increased from 1.7 to 4.6. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002128 [article] Spreadsheet-based modeling of liner wear impact on charge motion in tumbling mills [texte imprimé] / M. Yahyaei, Auteur ; S. Banisi, Auteur . - 2011 . - pp. 1213–1219. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1213–1219 Mots-clés : Comminution  SAG  milling  Modeling Résumé : Grinding remains the major constituent of the total cost of processing minerals in most applications. Charge motion is one of the key parameters affecting grinding efficiency and mill power draw. Although there have been numerous investigations on the effect of liner design on charge motion, the effect of charge profile due to liner wear during mill operation along the mill length has not received much attention. In this research, Powell’s analytical approach to calculate the charge trajectory with respect to the liner profile was used to develop a software based on Microsoft Excel© . As a case study, the liner wear profile of the Sarcheshmeh copper complex SAG mill was used to model the liner wear rate and calculate the changes of lifter face angle and lifter height during mill operation. Results were then used to determine charge motion in the SAG mill at any given operation time. The results indicated that after 4000 h of operation the lifters face angle increased from 14° to 47.1° and the height of lifters decreased from 15.2 to 5.8 cm. Modeling charge motion in the mill after 3000 h of operation showed 34° difference between the maximum and minimum of angles of impact along the mill length due to the nonuniform wear profile. It was also found that the variation in the pattern of the charge motion depends on the mill working hours and the distance of the desired point from the feed end. It was determined that the ratio of spacing to the height of lifters (S/H) plays an important role in the grinding efficiency and throughput. After 4000 h of operation, S/H ratio of the Sarcheshmeh SAG mill increased from 1.7 to 4.6. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002128

Sulphate ions removal from an aqueous solution / Renato Silva in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1220–1226 Titre : Sulphate ions removal from an aqueous solution : I. Co-precipitation with hydrolysed aluminum-bearing salts Type de document : texte imprimé Auteurs : Renato Silva, Auteur ; Luciana Cadorin, Auteur ; Jorge Rubio, Auteur Année de publication : 2011 Article en page(s) : pp. 1220–1226 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulphate  ions  removal  pH  Aluminum-bearing  salts  Co-precipitation Résumé : The removal of sulphate ions constitutes one of the main challenges in the mining, metallurgical and chemical industries, among others. Sulphate removal from aqueous streams is by far one of the most difficult and onerous tasks in these industries, and most existing processes are inefficient and costly. This work presents a method to remove sulphate ions in an acidic medium based on co-precipitation with aluminum salts, namely AlCl3 and a polyaluminum salt (PAC), followed by filtration. Herein, the different Al species react differently with sulphate, forming soluble and insoluble complexes, the latter of which causes insolubility and allows for the removal. The reaction kinetics depend on the activity of the so-called Alb species (which are classified as polymeric) and was proved here by different techniques. Better results were obtained with the inorganic salt AlCl3, when compared to PAC, probably because of the higher activity of the Al species. Co-precipitation of sulphate depends highly on the pH (which is optimal at 4.5), the mass ratio between reagents and sulphate ions (which is optimal at 7:1) and time (10 min). Finally, it was concluded that the technique proposed here has good potential for the treatment of sulphate-bearing effluents, including acid mining drainage (AMD). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002153 [article] Sulphate ions removal from an aqueous solution : I. Co-precipitation with hydrolysed aluminum-bearing salts [texte imprimé] / Renato Silva, Auteur ; Luciana Cadorin, Auteur ; Jorge Rubio, Auteur . - 2011 . - pp. 1220–1226. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1220–1226 Mots-clés : Sulphate  ions  removal  pH  Aluminum-bearing  salts  Co-precipitation Résumé : The removal of sulphate ions constitutes one of the main challenges in the mining, metallurgical and chemical industries, among others. Sulphate removal from aqueous streams is by far one of the most difficult and onerous tasks in these industries, and most existing processes are inefficient and costly. This work presents a method to remove sulphate ions in an acidic medium based on co-precipitation with aluminum salts, namely AlCl3 and a polyaluminum salt (PAC), followed by filtration. Herein, the different Al species react differently with sulphate, forming soluble and insoluble complexes, the latter of which causes insolubility and allows for the removal. The reaction kinetics depend on the activity of the so-called Alb species (which are classified as polymeric) and was proved here by different techniques. Better results were obtained with the inorganic salt AlCl3, when compared to PAC, probably because of the higher activity of the Al species. Co-precipitation of sulphate depends highly on the pH (which is optimal at 4.5), the mass ratio between reagents and sulphate ions (which is optimal at 7:1) and time (10 min). Finally, it was concluded that the technique proposed here has good potential for the treatment of sulphate-bearing effluents, including acid mining drainage (AMD). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002153

Selective leaching of arsenic and antimony from a tetrahedrite rich complex sulphide concentrate using alkaline sulphide solution / Samuel A. Awe in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1227–1236 Titre : Selective leaching of arsenic and antimony from a tetrahedrite rich complex sulphide concentrate using alkaline sulphide solution Type de document : texte imprimé Auteurs : Samuel A. Awe, Auteur ; Åke Sandström, Auteur Année de publication : 2011 Article en page(s) : pp. 1227–1236 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Selective  leaching  Tetrahedrite  Sodium  sulphide  Antimony  Impurity  element  Complex  sulphide  concentrate Résumé : Removal of impurity elements in copper metallurgy is one of the major problems encountered today since pure copper ore reserves are becoming exhausted and the resources of unexploited ores often contain relatively high amounts of impurity elements like antimony, arsenic, mercury and bismuth, which need to be eliminated. The present work is aimed at pre-treating a tetrahedrite rich complex sulphide concentrate by selective dissolution of the impurities, therefore, upgrading it for pyrometallurgical processing. To accomplish this, dissolution of antimony and arsenic by an alkaline sulphide lixiviant from the concentrate were investigated. The lixiviant proved selective and effective to dissolve these impurity elements from the concentrate with good recoveries. Further investigations on the factors influencing the leaching efficiency of the lixiviant were studied. The parameters considered were sulphide ion and hydroxide ion concentrations, mineral particle size, reaction temperature and leaching time. Analysis of the leach residue indicates that copper content of tetrahedrite has transformed into copper sulphides with the average chemical formula Cu1.64S. The grade and economic value of the concentrate were improved greatly after sulphide treatment, and therefore, suitable as a feedstock for smelting. The impurities have been reduced to low levels which are tolerable in the smelting furnace and consequently reduce both the treatment and environmental problem encountered when such concentrate is processed pyrometallurgically. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002177 [article] Selective leaching of arsenic and antimony from a tetrahedrite rich complex sulphide concentrate using alkaline sulphide solution [texte imprimé] / Samuel A. Awe, Auteur ; Åke Sandström, Auteur . - 2011 . - pp. 1227–1236. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1227–1236 Mots-clés : Selective  leaching  Tetrahedrite  Sodium  sulphide  Antimony  Impurity  element  Complex  sulphide  concentrate Résumé : Removal of impurity elements in copper metallurgy is one of the major problems encountered today since pure copper ore reserves are becoming exhausted and the resources of unexploited ores often contain relatively high amounts of impurity elements like antimony, arsenic, mercury and bismuth, which need to be eliminated. The present work is aimed at pre-treating a tetrahedrite rich complex sulphide concentrate by selective dissolution of the impurities, therefore, upgrading it for pyrometallurgical processing. To accomplish this, dissolution of antimony and arsenic by an alkaline sulphide lixiviant from the concentrate were investigated. The lixiviant proved selective and effective to dissolve these impurity elements from the concentrate with good recoveries. Further investigations on the factors influencing the leaching efficiency of the lixiviant were studied. The parameters considered were sulphide ion and hydroxide ion concentrations, mineral particle size, reaction temperature and leaching time. Analysis of the leach residue indicates that copper content of tetrahedrite has transformed into copper sulphides with the average chemical formula Cu1.64S. The grade and economic value of the concentrate were improved greatly after sulphide treatment, and therefore, suitable as a feedstock for smelting. The impurities have been reduced to low levels which are tolerable in the smelting furnace and consequently reduce both the treatment and environmental problem encountered when such concentrate is processed pyrometallurgically. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002177

Improvement of energy efficiency of rock comminution through reduction of thermal losses / Nenad Djordjevic in Minerals engineering, Vol. 23 N° 15 (Décembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1237–1244 Titre : Improvement of energy efficiency of rock comminution through reduction of thermal losses Type de document : texte imprimé Auteurs : Nenad Djordjevic, Auteur Année de publication : 2011 Article en page(s) : pp. 1237–1244 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Comminution  Process  optimization  Thermal  HPGR Résumé : The principal objective of this work was to develop a thermal imaging technique to measure the radiant heat coming from rock particles during or immediately after crushing, with the purpose of minimising energy losses while maintaining the efficiency of rock crushing. The main goal of the work was energy optimization of crushing in High Pressure Grinding Rolls (HPGR). We were able to perform reproducible measurements of the temperature increase that occurs during transient events such as dynamic rock breakage and HPGR crushing. Results obtained show that with an increase of energy introduced, there is an increase in the maximum temperature along the fractured surface as well as increases in the overall amount of thermal energy. Results obtained during HPGR testing clearly indicate that there is an optimum intensity of pressure to which rock needs to be exposed. Any further increase in pressure, results in only a marginal increase in fragmentation and a significant increase in unproductive heating of rock. We were also concerned about the effect of the size of particles coming into the HPGR. The fraction of new fine material (fines) produced during HPGR crushing is much higher in the case of feed with a narrow size distribution, i.e. without pre-existing fines. Significantly, improved performance is achieved with a reduced amount of net comminution energy. Observed relative crushing inefficiency of feed with a wide fragment size distribution (containing fines and coarse particles), is due to a large amount of pre-exiting fines, which clog the pore space between coarser fragments. In the compressed zone of the HPGR this creates approximately hydrostatic compressive loading conditions, which require much higher pressure (i.e. energy) to cause breakage of coarser particles. Experimental results indicate that up to 40% of energy can be saved through optimization of the applied pressure and modification of feed fragments size distribution. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002189 [article] Improvement of energy efficiency of rock comminution through reduction of thermal losses [texte imprimé] / Nenad Djordjevic, Auteur . - 2011 . - pp. 1237–1244. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 15 (Décembre 2010) . - pp. 1237–1244 Mots-clés : Comminution  Process  optimization  Thermal  HPGR Résumé : The principal objective of this work was to develop a thermal imaging technique to measure the radiant heat coming from rock particles during or immediately after crushing, with the purpose of minimising energy losses while maintaining the efficiency of rock crushing. The main goal of the work was energy optimization of crushing in High Pressure Grinding Rolls (HPGR). We were able to perform reproducible measurements of the temperature increase that occurs during transient events such as dynamic rock breakage and HPGR crushing. Results obtained show that with an increase of energy introduced, there is an increase in the maximum temperature along the fractured surface as well as increases in the overall amount of thermal energy. Results obtained during HPGR testing clearly indicate that there is an optimum intensity of pressure to which rock needs to be exposed. Any further increase in pressure, results in only a marginal increase in fragmentation and a significant increase in unproductive heating of rock. We were also concerned about the effect of the size of particles coming into the HPGR. The fraction of new fine material (fines) produced during HPGR crushing is much higher in the case of feed with a narrow size distribution, i.e. without pre-existing fines. Significantly, improved performance is achieved with a reduced amount of net comminution energy. Observed relative crushing inefficiency of feed with a wide fragment size distribution (containing fines and coarse particles), is due to a large amount of pre-exiting fines, which clog the pore space between coarser fragments. In the compressed zone of the HPGR this creates approximately hydrostatic compressive loading conditions, which require much higher pressure (i.e. energy) to cause breakage of coarser particles. Experimental results indicate that up to 40% of energy can be saved through optimization of the applied pressure and modification of feed fragments size distribution. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002189

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