Dépouillements

Solvent extraction and separation of palladium(II) and platinum(IV) from hydrochloric acid medium with dibutyl sulfoxide / Lu Pan in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1271–1276 Titre : Solvent extraction and separation of palladium(II) and platinum(IV) from hydrochloric acid medium with dibutyl sulfoxide Type de document : texte imprimé Auteurs : Lu Pan, Auteur ; Zu-de Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 1271–1276 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Palladium  Platinum  Dibutyl  sulfoxide  Solvent  extraction  Separation Résumé : The solvent extraction and separation performances of Pd(II) and Pt(IV) from hydrochloric acid solutions were investigated using dibutyl sulfoxide (DBSO) diluted in kerosene. Pd(II) was strongly extracted by a lower concentration DBSO in a lower concentration hydrochloric acid solution while the reverse was obtained for Pt(IV) extraction. Based on independent extraction and separation experiments of Pd(II) and Pt(IV), the separation parameters of Pd(II) and Pt(IV), including dibutyl sulfoxide concentration, contact time of aqueous and organic phases, organic/aqueous (O/A) phase ratio and H+ concentration of aqueous phase, were studied in detail, and the optimal separation parameters were obtained and summarized as the following: dibutyl sulfoxide concentration 0.6–1.2 mol dm−3, organic/aqueous (O/A) phase ratio 0.6–1.0, H+ concentration of aqueous phase 1.0–1.5 mol dm−3 and contact time of two phases 5 min. The as-prepared separation parameters were corroborated by the extraction and separation from a synthetic stock solution containing Pd(II), Pt(IV) as well as several common impurities like Fe(II), Cu(II) and Ni(II). The results revealed that Pd(II) could be separated efficiently from Pt(IV) with a high separation coefficient of Pd(II) an Pt(IV) (2.7 × 104) by predominantly controlling dibutyl sulfoxide and hydrochloric acid concentrations. The extraction saturation capacity of Pd(II) was determined from 1.0 mol dm−3 HCl solution with 3 mol dm−3 dibutyl sulfoxide and its experimental value exceeded 14 g dm−3 under the experimental conditions. Stripping of Pd(II) from loaded organic phase was performed using a mixed aqueous solution containing NH4Cl and ammonia solutes. Pd(II) (99.2%) was stripped using the stripping solution containing 3% (m/v) NH4Cl and 5 mol dm−3 ammonia, respectively. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900171X [article] Solvent extraction and separation of palladium(II) and platinum(IV) from hydrochloric acid medium with dibutyl sulfoxide [texte imprimé] / Lu Pan, Auteur ; Zu-de Zhang, Auteur . - 2010 . - pp. 1271–1276. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1271–1276 Mots-clés : Palladium  Platinum  Dibutyl  sulfoxide  Solvent  extraction  Separation Résumé : The solvent extraction and separation performances of Pd(II) and Pt(IV) from hydrochloric acid solutions were investigated using dibutyl sulfoxide (DBSO) diluted in kerosene. Pd(II) was strongly extracted by a lower concentration DBSO in a lower concentration hydrochloric acid solution while the reverse was obtained for Pt(IV) extraction. Based on independent extraction and separation experiments of Pd(II) and Pt(IV), the separation parameters of Pd(II) and Pt(IV), including dibutyl sulfoxide concentration, contact time of aqueous and organic phases, organic/aqueous (O/A) phase ratio and H+ concentration of aqueous phase, were studied in detail, and the optimal separation parameters were obtained and summarized as the following: dibutyl sulfoxide concentration 0.6–1.2 mol dm−3, organic/aqueous (O/A) phase ratio 0.6–1.0, H+ concentration of aqueous phase 1.0–1.5 mol dm−3 and contact time of two phases 5 min. The as-prepared separation parameters were corroborated by the extraction and separation from a synthetic stock solution containing Pd(II), Pt(IV) as well as several common impurities like Fe(II), Cu(II) and Ni(II). The results revealed that Pd(II) could be separated efficiently from Pt(IV) with a high separation coefficient of Pd(II) an Pt(IV) (2.7 × 104) by predominantly controlling dibutyl sulfoxide and hydrochloric acid concentrations. The extraction saturation capacity of Pd(II) was determined from 1.0 mol dm−3 HCl solution with 3 mol dm−3 dibutyl sulfoxide and its experimental value exceeded 14 g dm−3 under the experimental conditions. Stripping of Pd(II) from loaded organic phase was performed using a mixed aqueous solution containing NH4Cl and ammonia solutes. Pd(II) (99.2%) was stripped using the stripping solution containing 3% (m/v) NH4Cl and 5 mol dm−3 ammonia, respectively. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900171X

Selective adsorption of precious metals from hydrochloric acid solutions using porous carbon prepared from barley straw and rice husk / Rumi Chand in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1277–1282 Titre : Selective adsorption of precious metals from hydrochloric acid solutions using porous carbon prepared from barley straw and rice husk Type de document : texte imprimé Auteurs : Rumi Chand, Auteur ; Takanori Watari, Auteur ; Katsutoshi Inoue, Auteur Année de publication : 2010 Article en page(s) : pp. 1277–1282 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Rice  husk  Barley  straw  Porous  carbon  Adsorption  Precious  metals Résumé : Porous carbon was prepared by carbonization from agro-waste such as rice husk and barley straw to evaluate the adsorption of precious and base metals from metal solutions. The effects of hydrochloric acid concentration, metal ion concentration, and contact time on adsorption were examined. Rice husk carbon was found to be highly selective for Au(III) and inert to Pt(IV), Pd(II) and other base metals. Barley straw carbon adsorbed these three precious metal ions, but was inert to base metal ions such as Cu(II), Fe(III) and Ni(II). The maximum adsorption capacity of rice husk carbon for Au(III) was 0.76 mol/kg and the maximum adsorption capacity of barley straw carbon for Au(III), Pt(IV) and Pd(II) was 1.47, 0.39 and 0.64 mol/kg, respectively. The effectiveness of recovery of precious metals from industrial solution was also tested and barley straw carbon was found to be highly efficient and selective for the targeted metal ions in the presence of excess of other metal ions. Rice husk and barley straw carbon are thus potential alternatives to commercially available activated carbon as they have high selectivity and are efficient with low production costs. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001721 [article] Selective adsorption of precious metals from hydrochloric acid solutions using porous carbon prepared from barley straw and rice husk [texte imprimé] / Rumi Chand, Auteur ; Takanori Watari, Auteur ; Katsutoshi Inoue, Auteur . - 2010 . - pp. 1277–1282. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1277–1282 Mots-clés : Rice  husk  Barley  straw  Porous  carbon  Adsorption  Precious  metals Résumé : Porous carbon was prepared by carbonization from agro-waste such as rice husk and barley straw to evaluate the adsorption of precious and base metals from metal solutions. The effects of hydrochloric acid concentration, metal ion concentration, and contact time on adsorption were examined. Rice husk carbon was found to be highly selective for Au(III) and inert to Pt(IV), Pd(II) and other base metals. Barley straw carbon adsorbed these three precious metal ions, but was inert to base metal ions such as Cu(II), Fe(III) and Ni(II). The maximum adsorption capacity of rice husk carbon for Au(III) was 0.76 mol/kg and the maximum adsorption capacity of barley straw carbon for Au(III), Pt(IV) and Pd(II) was 1.47, 0.39 and 0.64 mol/kg, respectively. The effectiveness of recovery of precious metals from industrial solution was also tested and barley straw carbon was found to be highly efficient and selective for the targeted metal ions in the presence of excess of other metal ions. Rice husk and barley straw carbon are thus potential alternatives to commercially available activated carbon as they have high selectivity and are efficient with low production costs. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001721

Effect of ball size distribution on milling rate / François M. Katubilwa in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1283–1288 Titre : Effect of ball size distribution on milling rate Type de document : texte imprimé Auteurs : François M. Katubilwa, Auteur ; Michael H. Moys, Auteur Année de publication : 2010 Article en page(s) : pp. 1283–1288 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Grinding  Particle  size  Ball  size  Ball  size  distribution  Selection  function Résumé : This paper focuses on the determination of the selection function parameters α, a, μ, and Λ together with the exponent factors η and ξ describing the effect of ball size on milling rate for a South African coal. A series of batch grinding tests were carried out using three media single sizes, i.e. 30.6, 38.8, and 49.2 mm. Then two ball mixtures were successively considered. The original manufacturer’s recommended ball mixture was used to investigate the effect of ball size distribution on the selection function whereas the equilibrium ball mixture was used to validate the model. Results show that with the six parameters abovementioned, the charge mixture is fully characterized with about 5% deviation. Interestingly, the estimated parameters can be used in the simulator model allowing one to find the optimal ball charge distribution for a set of operational constraints. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001733 [article] Effect of ball size distribution on milling rate [texte imprimé] / François M. Katubilwa, Auteur ; Michael H. Moys, Auteur . - 2010 . - pp. 1283–1288. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1283–1288 Mots-clés : Grinding  Particle  size  Ball  size  Ball  size  distribution  Selection  function Résumé : This paper focuses on the determination of the selection function parameters α, a, μ, and Λ together with the exponent factors η and ξ describing the effect of ball size on milling rate for a South African coal. A series of batch grinding tests were carried out using three media single sizes, i.e. 30.6, 38.8, and 49.2 mm. Then two ball mixtures were successively considered. The original manufacturer’s recommended ball mixture was used to investigate the effect of ball size distribution on the selection function whereas the equilibrium ball mixture was used to validate the model. Results show that with the six parameters abovementioned, the charge mixture is fully characterized with about 5% deviation. Interestingly, the estimated parameters can be used in the simulator model allowing one to find the optimal ball charge distribution for a set of operational constraints. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001733

Experimental investigation of load behaviour of an industrial scale tumbling mill using noise and vibration signature techniques / Gangquan Si in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1289–1298 Titre : Experimental investigation of load behaviour of an industrial scale tumbling mill using noise and vibration signature techniques Type de document : texte imprimé Auteurs : Gangquan Si, Auteur ; Hui Cao, Auteur ; Yanbin Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 1289–1298 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Coal  Grinding  On-line  analysis  Process  instrumentation Résumé : Mill load (i.e. the load level of coal powder), which is critical in improving the production capacity and energy efficiency of pulverizing system in thermal power plant, has not been effectively monitored and controlled industrially. This paper investigates the load behaviour in an industrial scale tumbling mill under practical working conditions. A microphone and an accelerometer were installed to pick up mill noise and inlet trunnion vibration signals, respectively. By analyzing the sensitivity distributions of mill noise energy and mill vibration energy, characteristic power spectra (CPS) of mill noise and mill vibration were obtained. The CPS energy, centroid frequency and frequency domain variance of the mill noise and mill vibration were then investigated and compared under various working conditions. Experimental results show that the CPS energy of both mill noise and mill vibration can accurately represent the mill load. Moreover, the centroid frequency and frequency domain variance of mill noise can also be used to determine mill load. By combining these characteristics of mill noise and mill vibration, an improved estimation of mill load can be achieved. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001757 [article] Experimental investigation of load behaviour of an industrial scale tumbling mill using noise and vibration signature techniques [texte imprimé] / Gangquan Si, Auteur ; Hui Cao, Auteur ; Yanbin Zhang, Auteur . - 2010 . - pp. 1289–1298. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1289–1298 Mots-clés : Coal  Grinding  On-line  analysis  Process  instrumentation Résumé : Mill load (i.e. the load level of coal powder), which is critical in improving the production capacity and energy efficiency of pulverizing system in thermal power plant, has not been effectively monitored and controlled industrially. This paper investigates the load behaviour in an industrial scale tumbling mill under practical working conditions. A microphone and an accelerometer were installed to pick up mill noise and inlet trunnion vibration signals, respectively. By analyzing the sensitivity distributions of mill noise energy and mill vibration energy, characteristic power spectra (CPS) of mill noise and mill vibration were obtained. The CPS energy, centroid frequency and frequency domain variance of the mill noise and mill vibration were then investigated and compared under various working conditions. Experimental results show that the CPS energy of both mill noise and mill vibration can accurately represent the mill load. Moreover, the centroid frequency and frequency domain variance of mill noise can also be used to determine mill load. By combining these characteristics of mill noise and mill vibration, an improved estimation of mill load can be achieved. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001757

Adaptation of Acidithiobacillus ferrooxidans to high grade sphalerite concentrate / D.F. Haghshenas in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1299–1306 Titre : Adaptation of Acidithiobacillus ferrooxidans to high grade sphalerite concentrate Type de document : texte imprimé Auteurs : D.F. Haghshenas, Auteur ; E. Keshavarz Alamdari, Auteur ; M. Amouei Torkmahalleh, Auteur Année de publication : 2010 Article en page(s) : pp. 1299–1306 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Adaptation  Acidithiobacillus  ferrooxidans  High  grade  sphalerite  Bioleaching Résumé : In this study different strategies were employed for adapting Acidithiobacillus ferrooxidans cells to both Zn2+ ions and high grade sphalerite concentrate. The serial subculturing was found to be a very efficient strategy for adapting A. ferrooxidans cells to higher Zn2+ concentrations, as well as high grade sphalerite concentrate, provided that a suitable protocol was employed. Adaptation of A. ferrooxidans cells to 30 g/L Zn2+ significantly enhanced the rate of bioleaching of Zn2+ from high grade sphalerite concentrate. Preadaptation to Zn2+ ion also shortened the time required to adapt the cells to the concentrate. A. ferrooxidans PTCC 1642, exhibited a higher rate of Zn2+ bioleaching from high grade sphalerite concentrate compared to A. ferrooxidans DSMZ 583; however, due to the adaptation protocol employed the difference in performance of the two strains was not very great. Based on the results obtained in this study suggestions were given for the mechanisms during the adaptation of A. ferrooxidans cells to high grade sphalerite concentrate. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001769 [article] Adaptation of Acidithiobacillus ferrooxidans to high grade sphalerite concentrate [texte imprimé] / D.F. Haghshenas, Auteur ; E. Keshavarz Alamdari, Auteur ; M. Amouei Torkmahalleh, Auteur . - 2010 . - pp. 1299–1306. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1299–1306 Mots-clés : Adaptation  Acidithiobacillus  ferrooxidans  High  grade  sphalerite  Bioleaching Résumé : In this study different strategies were employed for adapting Acidithiobacillus ferrooxidans cells to both Zn2+ ions and high grade sphalerite concentrate. The serial subculturing was found to be a very efficient strategy for adapting A. ferrooxidans cells to higher Zn2+ concentrations, as well as high grade sphalerite concentrate, provided that a suitable protocol was employed. Adaptation of A. ferrooxidans cells to 30 g/L Zn2+ significantly enhanced the rate of bioleaching of Zn2+ from high grade sphalerite concentrate. Preadaptation to Zn2+ ion also shortened the time required to adapt the cells to the concentrate. A. ferrooxidans PTCC 1642, exhibited a higher rate of Zn2+ bioleaching from high grade sphalerite concentrate compared to A. ferrooxidans DSMZ 583; however, due to the adaptation protocol employed the difference in performance of the two strains was not very great. Based on the results obtained in this study suggestions were given for the mechanisms during the adaptation of A. ferrooxidans cells to high grade sphalerite concentrate. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001769

Saturated hydraulic conductivity of cemented paste backfill / M. Fall in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1307–1317 Titre : Saturated hydraulic conductivity of cemented paste backfill Type de document : texte imprimé Auteurs : M. Fall, Auteur ; D. Adrien, Auteur ; J. C. Célestin, Auteur Année de publication : 2010 Article en page(s) : pp. 1307–1317 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Cemented  paste  backfill  Tailings  Hydraulic  conductivity  Environmental  performance  Durability Résumé : The key design parameters of cemented paste backfill (CPB, a mix of tailings, water and binder) are strongly influenced by its saturated hydraulic conductivity (permeability). However, our understanding of the permeability of CPBs, as well as factors that affect it and its evolution with time, is limited. Hence, a laboratory investigation is conducted to study the hydraulic conductivity of CPBs and develop a model for predicting its evolution with time. The results show that the hydraulic conductivity of CPB is time-dependent. As the curing time increases, the hydraulic conductivity decreases. The permeability is also affected by the mix components. The permeability decreases as the binder content increases or the w/c ratio decreases. Medium tailings with 45% fine particles confer lower hydraulic conductivity to the CPB. The sulphate can have two opposite effects on the permeability of CPBs, contributing to an increase or decrease. However, the magnitude of the influence of the mix components depends on the curing time and is generally more pronounced at early ages (⩽7 days). Moreover, this study demonstrates that the hydraulic conductivity decreases with curing temperature and time for the studied CPBs. However, the effect of curing temperature on the hydraulic conductivity of CPBs is more significant in early age samples (up to 7 days) and depends on the binder type. Furthermore, the mechanical damage can significantly increase the hydraulic conductivity. Finally, the authors propose a simple function for the prediction of the evolution of the hydraulic conductivity of CPB with time. The validation results show that the developed model is able to predict the time-dependent change of the hydraulic conductivity with good accuracy. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001897 [article] Saturated hydraulic conductivity of cemented paste backfill [texte imprimé] / M. Fall, Auteur ; D. Adrien, Auteur ; J. C. Célestin, Auteur . - 2010 . - pp. 1307–1317. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1307–1317 Mots-clés : Cemented  paste  backfill  Tailings  Hydraulic  conductivity  Environmental  performance  Durability Résumé : The key design parameters of cemented paste backfill (CPB, a mix of tailings, water and binder) are strongly influenced by its saturated hydraulic conductivity (permeability). However, our understanding of the permeability of CPBs, as well as factors that affect it and its evolution with time, is limited. Hence, a laboratory investigation is conducted to study the hydraulic conductivity of CPBs and develop a model for predicting its evolution with time. The results show that the hydraulic conductivity of CPB is time-dependent. As the curing time increases, the hydraulic conductivity decreases. The permeability is also affected by the mix components. The permeability decreases as the binder content increases or the w/c ratio decreases. Medium tailings with 45% fine particles confer lower hydraulic conductivity to the CPB. The sulphate can have two opposite effects on the permeability of CPBs, contributing to an increase or decrease. However, the magnitude of the influence of the mix components depends on the curing time and is generally more pronounced at early ages (⩽7 days). Moreover, this study demonstrates that the hydraulic conductivity decreases with curing temperature and time for the studied CPBs. However, the effect of curing temperature on the hydraulic conductivity of CPBs is more significant in early age samples (up to 7 days) and depends on the binder type. Furthermore, the mechanical damage can significantly increase the hydraulic conductivity. Finally, the authors propose a simple function for the prediction of the evolution of the hydraulic conductivity of CPB with time. The validation results show that the developed model is able to predict the time-dependent change of the hydraulic conductivity with good accuracy. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001897

Evaluation of equilibrium, kinetic and thermodynamic parameters for biosorption of nickel(II) ions onto bacteria strain, Rhodococcus opacus / Javier Enrique Basurco Cayllahua in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1318–1325 Titre : Evaluation of equilibrium, kinetic and thermodynamic parameters for biosorption of nickel(II) ions onto bacteria strain, Rhodococcus opacus Type de document : texte imprimé Auteurs : Javier Enrique Basurco Cayllahua, Auteur ; Roberto José De Carvalho, Auteur ; Mauricio Leonardo Torem, Auteur Année de publication : 2010 Article en page(s) : pp. 1318–1325 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Biotechnology  Environmental  Nickel(II)  Bacteria  (Rhodococcus  opacus) Résumé : The present study explores the ability of Rhodococcus opacus bacteria strain for the removal of nickel(II) under different experimental conditions. The effects of relevant parameters such as solution pH, biomass loading, ionic strength, and temperature on nickel(II) biosorption capacity were evaluated. Although the tests were carried out using synthetic solutions, the results are representative of typical waste effluents from chemical, dyestuffs, battery manufacture, porcelain enameling, metallurgical industries and electroplating circuits. The sorption data followed the Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, and Sips isotherms. The maximum sorption capacity was found to be 7.63 mg g−1 at pH 5. Thermodynamic parameters have also been evaluated and the results show that the sorption process was spontaneous and endothermic in nature. The dynamics of the sorption process were studied and the values of rate constants for different kinetic models were calculated. The activation energy of biosorption (Ea) was determined as 12.56 kJ mol−1 using the Arrhenius equation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001915 [article] Evaluation of equilibrium, kinetic and thermodynamic parameters for biosorption of nickel(II) ions onto bacteria strain, Rhodococcus opacus [texte imprimé] / Javier Enrique Basurco Cayllahua, Auteur ; Roberto José De Carvalho, Auteur ; Mauricio Leonardo Torem, Auteur . - 2010 . - pp. 1318–1325. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1318–1325 Mots-clés : Biotechnology  Environmental  Nickel(II)  Bacteria  (Rhodococcus  opacus) Résumé : The present study explores the ability of Rhodococcus opacus bacteria strain for the removal of nickel(II) under different experimental conditions. The effects of relevant parameters such as solution pH, biomass loading, ionic strength, and temperature on nickel(II) biosorption capacity were evaluated. Although the tests were carried out using synthetic solutions, the results are representative of typical waste effluents from chemical, dyestuffs, battery manufacture, porcelain enameling, metallurgical industries and electroplating circuits. The sorption data followed the Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, and Sips isotherms. The maximum sorption capacity was found to be 7.63 mg g−1 at pH 5. Thermodynamic parameters have also been evaluated and the results show that the sorption process was spontaneous and endothermic in nature. The dynamics of the sorption process were studied and the values of rate constants for different kinetic models were calculated. The activation energy of biosorption (Ea) was determined as 12.56 kJ mol−1 using the Arrhenius equation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001915

Cemented products containing waste from mineral processing and bioleaching / B. K. C. Chan in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1326–1333 Titre : Cemented products containing waste from mineral processing and bioleaching Type de document : texte imprimé Auteurs : B. K. C. Chan, Auteur ; S. Bouzalakos, Auteur ; A.W.L. Dudeney, Auteur Année de publication : 2010 Article en page(s) : pp. 1326–1333 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Cemented  fill  Environmental  Leaching  Mineral  processing  Waste  processing Résumé : The characteristics of cemented products ranging in initial consistency from ‘paste-like’ to ‘flowable’, relevant to paste backfill and backfill with controlled low strength materials (CLSM), respectively, were compared for mixes incorporating waste from pilot scale bioleaching of European refractory gold, copper and copper/nickel sulphide flotation concentrates. Compositional and structural properties were linked to mechanical strength, hydraulic conductivity and hydrolytic stability (leachability) in fabricated laboratory specimens containing sand, pulverised fuel ash, waste and Portland cement in the proportions 70, 15, 10 and 5, respectively, together with variable quantities of water. In some experiments, sand was replaced by flotation tailings. The results showed that mixtures containing 10% of waste with 15.0–37.5% water by mass gave cemented materials with unconfined compressive strength (UCS) in the range 0.4–3.0 MPa after 28 days of hardening, this range encompassing typical paste-fill and CLSM formulations. They also indicated formulations giving maximum UCS and retention of strength at higher water content in the presence of the (finer sized) waste. Hydraulic conductivity (10−7–10−9 m/s) was comparable to commercial CLSM. Chemical analysis indicated low levels of most toxic elements and correspondingly low diffusion leaching, thus reducing requirements for special lining or encapsulation procedures to avoid groundwater contamination. However, chromium leaching, for example, remained an issue, thus indicating a need for further development before regulatory acceptance and deployment in field applications can become feasible. The formulated materials are consistent in principle with a scheme of integrated waste management based on designed combinations of paste (for mine backfill), CLSM (for engineering foundation construction) and mineral bulk (for site landscape/soil restoration). In particular, they facilitate production of different materials for paste backfill and CLSM applications by judicious adjustment of water content. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001927 [article] Cemented products containing waste from mineral processing and bioleaching [texte imprimé] / B. K. C. Chan, Auteur ; S. Bouzalakos, Auteur ; A.W.L. Dudeney, Auteur . - 2010 . - pp. 1326–1333. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1326–1333 Mots-clés : Cemented  fill  Environmental  Leaching  Mineral  processing  Waste  processing Résumé : The characteristics of cemented products ranging in initial consistency from ‘paste-like’ to ‘flowable’, relevant to paste backfill and backfill with controlled low strength materials (CLSM), respectively, were compared for mixes incorporating waste from pilot scale bioleaching of European refractory gold, copper and copper/nickel sulphide flotation concentrates. Compositional and structural properties were linked to mechanical strength, hydraulic conductivity and hydrolytic stability (leachability) in fabricated laboratory specimens containing sand, pulverised fuel ash, waste and Portland cement in the proportions 70, 15, 10 and 5, respectively, together with variable quantities of water. In some experiments, sand was replaced by flotation tailings. The results showed that mixtures containing 10% of waste with 15.0–37.5% water by mass gave cemented materials with unconfined compressive strength (UCS) in the range 0.4–3.0 MPa after 28 days of hardening, this range encompassing typical paste-fill and CLSM formulations. They also indicated formulations giving maximum UCS and retention of strength at higher water content in the presence of the (finer sized) waste. Hydraulic conductivity (10−7–10−9 m/s) was comparable to commercial CLSM. Chemical analysis indicated low levels of most toxic elements and correspondingly low diffusion leaching, thus reducing requirements for special lining or encapsulation procedures to avoid groundwater contamination. However, chromium leaching, for example, remained an issue, thus indicating a need for further development before regulatory acceptance and deployment in field applications can become feasible. The formulated materials are consistent in principle with a scheme of integrated waste management based on designed combinations of paste (for mine backfill), CLSM (for engineering foundation construction) and mineral bulk (for site landscape/soil restoration). In particular, they facilitate production of different materials for paste backfill and CLSM applications by judicious adjustment of water content. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001927

Kinetic model for the multi-spigot hydrosizer / E.F. Crespo in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1334–1343 Titre : Kinetic model for the multi-spigot hydrosizer Type de document : texte imprimé Auteurs : E.F. Crespo, Auteur Année de publication : 2010 Article en page(s) : pp. 1334–1343 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Classification  Modelling  Simulation Résumé : A kinetic mathematical model was developed to describe the operation of the multi-spigot hydrosizer. The model is based on the description of two fundamental mechanisms: particle segregation and particle dispersion. Starting from the integral form of the continuity equation, applied to a discretized space, a system of ordinary differential equations, which includes the two mechanisms, was derived. The resulting system of differential equations describes the work of the teeter bed that exists inside each classifying chamber of the hydrosizer. A computational algorithm was developed to solve the model equations, based on a second-order precision predictor–corrector method. Timed samples were collected on the new six-spigot MEP Hydrosizer at present time working in Barroca Grande plant at Panasqueira mine (Portugal). The experimental data consist of the size distributions, the grades in tungsten trioxide and arsenic for each size class, the volume flow rates, and the pulp densities for each product yielded by the hydrosizer. The model was fitted to the experimental data, employing an optimization algorithm for non-linear unconstrained least-squares problems. It was found good agreement between the simulated and experimental results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001952 [article] Kinetic model for the multi-spigot hydrosizer [texte imprimé] / E.F. Crespo, Auteur . - 2010 . - pp. 1334–1343. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1334–1343 Mots-clés : Classification  Modelling  Simulation Résumé : A kinetic mathematical model was developed to describe the operation of the multi-spigot hydrosizer. The model is based on the description of two fundamental mechanisms: particle segregation and particle dispersion. Starting from the integral form of the continuity equation, applied to a discretized space, a system of ordinary differential equations, which includes the two mechanisms, was derived. The resulting system of differential equations describes the work of the teeter bed that exists inside each classifying chamber of the hydrosizer. A computational algorithm was developed to solve the model equations, based on a second-order precision predictor–corrector method. Timed samples were collected on the new six-spigot MEP Hydrosizer at present time working in Barroca Grande plant at Panasqueira mine (Portugal). The experimental data consist of the size distributions, the grades in tungsten trioxide and arsenic for each size class, the volume flow rates, and the pulp densities for each product yielded by the hydrosizer. The model was fitted to the experimental data, employing an optimization algorithm for non-linear unconstrained least-squares problems. It was found good agreement between the simulated and experimental results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001952

Horizontal roller mill (Horomill®) application versus hybrid HPGR/ball milling in finish grinding of cement / Ö. Genç in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1344–1349 Titre : Horizontal roller mill (Horomill®) application versus hybrid HPGR/ball milling in finish grinding of cement Type de document : texte imprimé Auteurs : Ö. Genç, Auteur ; A. H. Benzer, Auteur Année de publication : 2010 Article en page(s) : pp. 1344–1349 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Grinding  Classification  Sizing  Mass  balancing Résumé : Industrial scale Horomill® and hybrid HPGR/two-compartment ball mill applications at puzzolanic portland cement production were presented with emphasis on the general operational characteristics of the circuit configurations, size reduction and energy efficiencies of the Horomill® and two-compartment ball mill grinding conditions. Horomill® circuit configuration indicated to have advantages in terms of production of high strength cement as compared to Hybrid HPGR/two-compartment ball milling, depending on the classification performance of the separators influencing the circuit performance. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002246 [article] Horizontal roller mill (Horomill®) application versus hybrid HPGR/ball milling in finish grinding of cement [texte imprimé] / Ö. Genç, Auteur ; A. H. Benzer, Auteur . - 2010 . - pp. 1344–1349. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1344–1349 Mots-clés : Grinding  Classification  Sizing  Mass  balancing Résumé : Industrial scale Horomill® and hybrid HPGR/two-compartment ball mill applications at puzzolanic portland cement production were presented with emphasis on the general operational characteristics of the circuit configurations, size reduction and energy efficiencies of the Horomill® and two-compartment ball mill grinding conditions. Horomill® circuit configuration indicated to have advantages in terms of production of high strength cement as compared to Hybrid HPGR/two-compartment ball milling, depending on the classification performance of the separators influencing the circuit performance. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002246

Dynamic modelling of copper solvent extraction mixer–settler units / C.M. Moreno in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1350–1358 Titre : Dynamic modelling of copper solvent extraction mixer–settler units Type de document : texte imprimé Auteurs : C.M. Moreno, Auteur ; J.R. Pérez-Correa, Auteur ; A. Otero, Auteur Année de publication : 2010 Article en page(s) : pp. 1350–1358 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Extractive  metallurgy  Hydrometallurgy  Simulation Résumé : The copper Leaching, Solvent Extraction and Electrowinning circuit (LX–SX–EW) is one of the most effective processes for extracting copper from low grade ores. This work focuses on the liquid–liquid extraction SX sub-process, since many difficult to handle operational problems within LX–SX–EW circuits are related to SX malfunction. Controlling these problems better can reduce operational costs and increase recovery and copper production. Realistic dynamic simulation is a standard tool nowadays to design and assess more effective control strategies. In this work we present a general dynamic model for SX mixer–settlers, and applied it to two different units, one located in an extraction stage and the other in a stripping stage of a copper plant. The model includes a non-trivial settler hydrodynamics represented by a set of nonlinear differential equations for both mixer and settler units. The mixer is modelled as a continuous stirred tank reactor and the settler as a hydrodynamic circuit combining series and parallel connections of continuous stirred tank and plug flow reactors. The model was calibrated with industrial plant data, resulting in realistic simulations of outlet copper concentrations. Using the proposed model, we obtained better fitting than that achieved with simpler settler models that include only a time delay. The model fitting parameters provide sufficient flexibility to accurately reproduce the dynamics of different units in industrial plants. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002283 [article] Dynamic modelling of copper solvent extraction mixer–settler units [texte imprimé] / C.M. Moreno, Auteur ; J.R. Pérez-Correa, Auteur ; A. Otero, Auteur . - 2010 . - pp. 1350–1358. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1350–1358 Mots-clés : Extractive  metallurgy  Hydrometallurgy  Simulation Résumé : The copper Leaching, Solvent Extraction and Electrowinning circuit (LX–SX–EW) is one of the most effective processes for extracting copper from low grade ores. This work focuses on the liquid–liquid extraction SX sub-process, since many difficult to handle operational problems within LX–SX–EW circuits are related to SX malfunction. Controlling these problems better can reduce operational costs and increase recovery and copper production. Realistic dynamic simulation is a standard tool nowadays to design and assess more effective control strategies. In this work we present a general dynamic model for SX mixer–settlers, and applied it to two different units, one located in an extraction stage and the other in a stripping stage of a copper plant. The model includes a non-trivial settler hydrodynamics represented by a set of nonlinear differential equations for both mixer and settler units. The mixer is modelled as a continuous stirred tank reactor and the settler as a hydrodynamic circuit combining series and parallel connections of continuous stirred tank and plug flow reactors. The model was calibrated with industrial plant data, resulting in realistic simulations of outlet copper concentrations. Using the proposed model, we obtained better fitting than that achieved with simpler settler models that include only a time delay. The model fitting parameters provide sufficient flexibility to accurately reproduce the dynamics of different units in industrial plants. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002283

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