A defined mesophilic consortium including an iron oxidizing bacterium and a sulfur oxidizing bacterium was constructed to evaluate its ability for bioleaching a flotation concentrate from Andacollo mine in Neuqué...A defined mesophilic consortium including an iron oxidizing bacterium and a sulfur oxidizing bacterium was constructed to evaluate its ability for bioleaching a flotation concentrate from Andacollo mine in Neuquén,Argentina.Experiments were performed in shake flasks with a pulp density of10%(w/v),using a basal salt medium containing ferrous iron at pH1.8.The leaching solutions were analyzed for pH,redox potential(using specifics electrodes),ferrous iron(by UV-Vis spectrophotometry)and metal concentrations(by atomic absorption spectroscopy).The results showed that the consortium was able to reduce the refractory behavior of the concentrate,allowing91.6%of gold recovery;at the same time,high dissolution of copper and zinc was reached.These dissolutions followed a shrinking core kinetic model.According to this model,the copper solubilization was controlled by diffusion through a product layer(mainly jarosite),while zinc dissolution did not show a defined control step.This designed consortium,composed of bacterial strains with specific physiological abilities,could be useful not only to optimize gold recovery but also to decrease the leachates metallic charge,which would be an environmental advantage.展开更多
For the high sulfur refractory gold concentrate with 41.82%sulfur and 15.12 g/t gold,of which 82.11%was wrapped in sulfide,a well-controlled stirring tank leaching was carried out to improve the bio-oxidation efficien...For the high sulfur refractory gold concentrate with 41.82%sulfur and 15.12 g/t gold,of which 82.11%was wrapped in sulfide,a well-controlled stirring tank leaching was carried out to improve the bio-oxidation efficiency.Results show that bio-oxidation pretreatment can greatly improve the gold recovery rate of high-sulfur refractory gold concentrate,and at the optimum pH 1.3 in this study,compared with the process without pH control,the oxidation rate of sulfur increased from 79.31%to 83.29%,while the recovery rate of gold increased from 76.54%to 83.23%;under this condition the activity of mixed culture could be sustained and the formation of jarosite could diminish.The results also displayed that for the high sulfur refractory gold concentrate,the recovery of gold is positively correlated with the oxidation rate of sulfur,and the recovery rate of gold increases with the increase of sulfur oxidation rate within a certain range.展开更多
This paper discusses two alternative ways of existence of the human being： participation in the concept of reason and participation in the events of the world. It is argued that the traditional Western philosophy fro...This paper discusses two alternative ways of existence of the human being： participation in the concept of reason and participation in the events of the world. It is argued that the traditional Western philosophy from Parmenides and Plato to R. Descartes, I. Kant, and G. Hegel can be described as the participation in the concept of reason. This tradition is characterized by the goal to assimilate the things of the world by concept of reason and in accordance with a project reason, to change the world. This led to the ecological catastrophe. We can overcome ecological catastrophe successfully only when we change the paradigm and shift to the paradigm of participation in the events of the world. The article is based on A. Badiou＇s conception of event which is contrasted with Descartes＇ conception of the event. Argumentation of the article shows the importance of B. Spinoza＇s monistic philosophy for our epoch, which is struck by the ecological disaster. This philosophy is not characterised by the war between things and thoughts, because both thoughts and things are attributes expressing the same God or Nature and are not in conflict with one another.展开更多
Aims We aimed to elucidate the driving forces underlying the geographical distribution of spruce forests,as well as the morphological and phylogenetic divergence among spruce species in China.Methods One hundred and s...Aims We aimed to elucidate the driving forces underlying the geographical distribution of spruce forests,as well as the morphological and phylogenetic divergence among spruce species in China.Methods One hundred and seventy two sites across the entire range of spruce forests in China(23°–53°N,75°–134°E,250–4300 m a.s.l.)were sampled for species composition,geographical coordinates,and topographic and climatic variables.Sixteen spruce taxa,which are naturally distributed in China,were respectively grouped into morphologically defined sections and phylogenetically distinct clades.Multivariate approaches,including two-way indicator species analysis,principal components analysis,detrended correspondence analysis,canonical correspondence analysis(CCA),and partial CCA,were used for data analysis.Important Findings The 172 samples grouped into 13 spruce forests,the geographical distributions of which were closely related to climate and geographical location.The variation in species composition explained by the geographical coordinates(32.01%)was significantly higher than that explained by the climatic(27.76%)and topographic variables(23.32%).Of the three morphologically defined sections,sect.Omorica occurred mainly in wetter habitats with a mean annual precipitation of ca.229 mm and 426 mm higher than the habitats of sect.Casicta and sect.Picea(P<0.01),respectively.Of the two phylogenetically distinct clades,Clade-II(an older clade)occurred in habitats with warm winters and cool summers whose mean temperature in the coldest month was ca.8–10℃ higher,yet accumulated temperature during the growing season(≥5℃)was ca.297–438℃ lower,than the habitats of Clade-III(a younger clade)(P<0.01).Our data support the hypothesis that geographical location may be a greater determinant of variation in species composition.In addition,moisture conditions tend to be the key determinants that account for the divergence among the morphologically defined sections,while the phylogenetic divergence among spruce species is mainly affected by temperature conditions.While the clades or sections of the spruce species in question carry strong climatic signals,their divergences are subject to different selective pressures.展开更多
基金supported by PIP 0368 from CONICET and PICT 0630 and 0623 from ANPCyT
文摘A defined mesophilic consortium including an iron oxidizing bacterium and a sulfur oxidizing bacterium was constructed to evaluate its ability for bioleaching a flotation concentrate from Andacollo mine in Neuquén,Argentina.Experiments were performed in shake flasks with a pulp density of10%(w/v),using a basal salt medium containing ferrous iron at pH1.8.The leaching solutions were analyzed for pH,redox potential(using specifics electrodes),ferrous iron(by UV-Vis spectrophotometry)and metal concentrations(by atomic absorption spectroscopy).The results showed that the consortium was able to reduce the refractory behavior of the concentrate,allowing91.6%of gold recovery;at the same time,high dissolution of copper and zinc was reached.These dissolutions followed a shrinking core kinetic model.According to this model,the copper solubilization was controlled by diffusion through a product layer(mainly jarosite),while zinc dissolution did not show a defined control step.This designed consortium,composed of bacterial strains with specific physiological abilities,could be useful not only to optimize gold recovery but also to decrease the leachates metallic charge,which would be an environmental advantage.
基金Projects(51704028,51574036)supported by the National Natural Science Foundation of ChinaProject supported by Program for Key Laboratory of Biohydrometallurgy of Ministry of Education Foundation,China。
文摘For the high sulfur refractory gold concentrate with 41.82%sulfur and 15.12 g/t gold,of which 82.11%was wrapped in sulfide,a well-controlled stirring tank leaching was carried out to improve the bio-oxidation efficiency.Results show that bio-oxidation pretreatment can greatly improve the gold recovery rate of high-sulfur refractory gold concentrate,and at the optimum pH 1.3 in this study,compared with the process without pH control,the oxidation rate of sulfur increased from 79.31%to 83.29%,while the recovery rate of gold increased from 76.54%to 83.23%;under this condition the activity of mixed culture could be sustained and the formation of jarosite could diminish.The results also displayed that for the high sulfur refractory gold concentrate,the recovery of gold is positively correlated with the oxidation rate of sulfur,and the recovery rate of gold increases with the increase of sulfur oxidation rate within a certain range.
文摘This paper discusses two alternative ways of existence of the human being： participation in the concept of reason and participation in the events of the world. It is argued that the traditional Western philosophy from Parmenides and Plato to R. Descartes, I. Kant, and G. Hegel can be described as the participation in the concept of reason. This tradition is characterized by the goal to assimilate the things of the world by concept of reason and in accordance with a project reason, to change the world. This led to the ecological catastrophe. We can overcome ecological catastrophe successfully only when we change the paradigm and shift to the paradigm of participation in the events of the world. The article is based on A. Badiou＇s conception of event which is contrasted with Descartes＇ conception of the event. Argumentation of the article shows the importance of B. Spinoza＇s monistic philosophy for our epoch, which is struck by the ecological disaster. This philosophy is not characterised by the war between things and thoughts, because both thoughts and things are attributes expressing the same God or Nature and are not in conflict with one another.
基金supported by National Natural Science Foundation of China(41571045).
文摘Aims We aimed to elucidate the driving forces underlying the geographical distribution of spruce forests,as well as the morphological and phylogenetic divergence among spruce species in China.Methods One hundred and seventy two sites across the entire range of spruce forests in China(23°–53°N,75°–134°E,250–4300 m a.s.l.)were sampled for species composition,geographical coordinates,and topographic and climatic variables.Sixteen spruce taxa,which are naturally distributed in China,were respectively grouped into morphologically defined sections and phylogenetically distinct clades.Multivariate approaches,including two-way indicator species analysis,principal components analysis,detrended correspondence analysis,canonical correspondence analysis(CCA),and partial CCA,were used for data analysis.Important Findings The 172 samples grouped into 13 spruce forests,the geographical distributions of which were closely related to climate and geographical location.The variation in species composition explained by the geographical coordinates(32.01%)was significantly higher than that explained by the climatic(27.76%)and topographic variables(23.32%).Of the three morphologically defined sections,sect.Omorica occurred mainly in wetter habitats with a mean annual precipitation of ca.229 mm and 426 mm higher than the habitats of sect.Casicta and sect.Picea(P<0.01),respectively.Of the two phylogenetically distinct clades,Clade-II(an older clade)occurred in habitats with warm winters and cool summers whose mean temperature in the coldest month was ca.8–10℃ higher,yet accumulated temperature during the growing season(≥5℃)was ca.297–438℃ lower,than the habitats of Clade-III(a younger clade)(P<0.01).Our data support the hypothesis that geographical location may be a greater determinant of variation in species composition.In addition,moisture conditions tend to be the key determinants that account for the divergence among the morphologically defined sections,while the phylogenetic divergence among spruce species is mainly affected by temperature conditions.While the clades or sections of the spruce species in question carry strong climatic signals,their divergences are subject to different selective pressures.
