Pyrolusite was added in the bioleaching process to enhance the bio-oxidation process. Bioleaching tests at different dosages of pyrolusite ore, pH and inoculation amounts of Acidithiobacillus ferrooxidans were studied...Pyrolusite was added in the bioleaching process to enhance the bio-oxidation process. Bioleaching tests at different dosages of pyrolusite ore, pH and inoculation amounts of Acidithiobacillus ferrooxidans were studied. The results showed that the time of the bio-oxidation process was decreased obviously and the arsenic leaching rate reached 94.4% after the bioleaching. The bio-oxidation of arsenopyrite and the effective extraction of manganese from pyrolusite were achieved by the bioleaching process. After bioleaching, the leaching rate of gold from the reaction residues reached 95.8% by cyanide leaching. In the bio-oxidation process, pyrolusite increased the redox potential of the solution to accelerate the bioleaching rate. The experiment showed that there were two reaction modes in the bioleaching process.展开更多
The binding of metallic contaminants （Pb, Cd, and Zn） and As on soil constituents was studied on four highly contaxninated alluvial soil profiles from the mining/smelting district of Pribram （Czech Republic） using...The binding of metallic contaminants （Pb, Cd, and Zn） and As on soil constituents was studied on four highly contaxninated alluvial soil profiles from the mining/smelting district of Pribram （Czech Republic） using a combination of mineralogical and chemical methods. Sequential extraction analysis （SEA） was supplemented by mineralogical investigation of both bulk samples and heavy mineral fractions using X-ray diffraction analysis （XRD） and scanning electron microscopy with an energy dispersive X-ray spectrometer （SEM/EDS）. The mineralogy of Fe and Mn oxides was studied by voltammetry of microparticles （VMP） and diffuse reflectance spectrometry （DRS）. Zinc and Pb were predominantly bound in the reducible fraction attributed to Fe oxides and Mn oxides （mainly birnessite, Na4Mn14O27.9H2O）, which were detected in soils by XRD and SEM/EDS. In contrast, Cd was the most mobile contaminant and was predominantly present in the exchangeable fraction. Arsenic was bound to the residual and reducible fractions （corresponding to Fe oxides or to unidentified Fe-Pb arsenates）. SEM/EDS observations indicate the predominant affinity of Pb for Mn oxides, and to a lesser extent, for Fe oxides. Thus, a more suitable SEA procedure should be used for these mining-affected soils to distinguish between the contaminant fraction bound to Mn oxides and Fe oxides.展开更多
Minerals which enter lake-marsh ores composition are very diverse. There are two large classes of ores： ferrous and manganese-ferrous ores. Each class is divided into groups according to its mineral composition. In t...Minerals which enter lake-marsh ores composition are very diverse. There are two large classes of ores： ferrous and manganese-ferrous ores. Each class is divided into groups according to its mineral composition. In this investigation, ferrous ore sample （Chagodostcha） and manganese-ferrous ore samples （Totyma-2 and Mologa-2） were considered. All samples in the initial state are contaminated with a-quartz and Ab-An feldspars. Thus for purification of the samples, direct flotation method with kerosene agent were used. As a result, almost all impurities were removed from the samples. With the X-ray diffraction method, the authors identified following phases： goethite （ferrous ore） and birnessite （manganese-ferrous ores）. Also, the authors used electron probe microanalysis of the original and purified probes and it showed the presence of such impurities as Ca, K, Mg and Ba in birnessite from the manganese-ferrous ores, and AI and Mn impurities in goethite from the ferrous ore. All ore minerals are in a nanocrystalline state （crystallite size is about 10 nm）.展开更多
The mineralogical and micromorphological characteristics of Si-Fe-Mn oxyhydroxides from the dacite-hosted PACMANUS hydrothermal field were analyzed.The samples are poorly crystallized Si-Fe-Mn oxyhydroxides with minor...The mineralogical and micromorphological characteristics of Si-Fe-Mn oxyhydroxides from the dacite-hosted PACMANUS hydrothermal field were analyzed.The samples are poorly crystallized Si-Fe-Mn oxyhydroxides with minor birnessite, todorokite, nontronite, goethite, and opal-A.There are some microtextures which are rather like fossil microbes such as the filamentous silica and the hollow pipes.Flakes of nontronite crystals are found either forming a honeycomb texture or distrib- uted on the surface of the hollow pipes.Nontronite is the product precipitated from low-temperature hydrothermal fluids, and microbes may play a role in its formation.Si-Fe-Mn oxyhydroxides have two kinds of nuclei: Si-Mn nuclei and Si nuclei, both enveloped by the similar Si-Fe outer layer, existing in the rod-shaped oxyhydroxide and spheroidal oxyhydroxide, respectively.In the Si-Mn nuclei, the concentration of SiO2 is between 39.32 wt% and 86.31 wt%, and MnO concentration is between 4.97 wt% and 27.01 wt%, but Fe2O3 concentration is very low (0.54 wt%-3.43 wt%).In the Si nucleus the concentration of SiO2 is 90.17 wt%, but concentration of MnO and Fe2O3 are low, with 0.06 wt% and 3.47 wt%, respectively.The formation of the Si-Mn nucleus is closely related to microbes, whereas the Si nucleus is of inorganic origin.展开更多
The coexistence of magnetic ordering and ferroelectricity, ing on the origin of ferroelectricity, multiferroic materials known as multiferroics, has drawn a lot of research effort. Depend can be classified into differ...The coexistence of magnetic ordering and ferroelectricity, ing on the origin of ferroelectricity, multiferroic materials known as multiferroics, has drawn a lot of research effort. Depend can be classified into different groups. In this paper, we review re cent progress in the field of multiferroics induced by different forms of charge ordering. In addition to a general description of charge order and electronic ferroelectricity, we focus on two specific systems： （1） charge order with frustration in RFe2O4 （R=Lu, Yb） system; （2） charge ordered perovskite manganites of the type （R1-xCax）MnO3 （R=La, Pr）. The charge ordering can be tuned by external electric fields, which results in pronounced magnetoelectric effects and strong dielectric tunability. Other materials and possible candidates with charge order induced multiferroics are also briefly summarized.展开更多
基金Project(2015ZX07205-003)supported by the National Water Pollution Control and Treatment Science,ChinaProject(DY125-15-T-08)supported by China Ocean Mineral Resource R&D Association+1 种基金Project(2012BAB07B05)supported by the National Key Technology R&D Program of ChinaProject(2012AA062401)supported by the National High-tech Research and Development Program of China
文摘Pyrolusite was added in the bioleaching process to enhance the bio-oxidation process. Bioleaching tests at different dosages of pyrolusite ore, pH and inoculation amounts of Acidithiobacillus ferrooxidans were studied. The results showed that the time of the bio-oxidation process was decreased obviously and the arsenic leaching rate reached 94.4% after the bioleaching. The bio-oxidation of arsenopyrite and the effective extraction of manganese from pyrolusite were achieved by the bioleaching process. After bioleaching, the leaching rate of gold from the reaction residues reached 95.8% by cyanide leaching. In the bio-oxidation process, pyrolusite increased the redox potential of the solution to accelerate the bioleaching rate. The experiment showed that there were two reaction modes in the bioleaching process.
基金the Higher Education Development Fund (FRV) of the Ministry of Education, Youth and Sportsof the Czech Republic (No.217/2005)the Czech Science Foundation (No.GAR 205/04/1292)the Ministry ofEducation, Youth and Sports of the Czech Republic (Nos.MSM 6046070901 and MSM 0021620855).
文摘The binding of metallic contaminants （Pb, Cd, and Zn） and As on soil constituents was studied on four highly contaxninated alluvial soil profiles from the mining/smelting district of Pribram （Czech Republic） using a combination of mineralogical and chemical methods. Sequential extraction analysis （SEA） was supplemented by mineralogical investigation of both bulk samples and heavy mineral fractions using X-ray diffraction analysis （XRD） and scanning electron microscopy with an energy dispersive X-ray spectrometer （SEM/EDS）. The mineralogy of Fe and Mn oxides was studied by voltammetry of microparticles （VMP） and diffuse reflectance spectrometry （DRS）. Zinc and Pb were predominantly bound in the reducible fraction attributed to Fe oxides and Mn oxides （mainly birnessite, Na4Mn14O27.9H2O）, which were detected in soils by XRD and SEM/EDS. In contrast, Cd was the most mobile contaminant and was predominantly present in the exchangeable fraction. Arsenic was bound to the residual and reducible fractions （corresponding to Fe oxides or to unidentified Fe-Pb arsenates）. SEM/EDS observations indicate the predominant affinity of Pb for Mn oxides, and to a lesser extent, for Fe oxides. Thus, a more suitable SEA procedure should be used for these mining-affected soils to distinguish between the contaminant fraction bound to Mn oxides and Fe oxides.
文摘Minerals which enter lake-marsh ores composition are very diverse. There are two large classes of ores： ferrous and manganese-ferrous ores. Each class is divided into groups according to its mineral composition. In this investigation, ferrous ore sample （Chagodostcha） and manganese-ferrous ore samples （Totyma-2 and Mologa-2） were considered. All samples in the initial state are contaminated with a-quartz and Ab-An feldspars. Thus for purification of the samples, direct flotation method with kerosene agent were used. As a result, almost all impurities were removed from the samples. With the X-ray diffraction method, the authors identified following phases： goethite （ferrous ore） and birnessite （manganese-ferrous ores）. Also, the authors used electron probe microanalysis of the original and purified probes and it showed the presence of such impurities as Ca, K, Mg and Ba in birnessite from the manganese-ferrous ores, and AI and Mn impurities in goethite from the ferrous ore. All ore minerals are in a nanocrystalline state （crystallite size is about 10 nm）.
基金supported by National Natural Science Foundation of China(Grant No.40830849)National Key Basic Research Program of China(Grant No.2013CB429700)+1 种基金Shandong Province Natural Science Foundation of China for Distin-guished Young Scholars(Grant No.JQ200913)the Pilot Project of Knowledge Innovation Project,Chinese Academy of Sciences(Grant No.KZCX2-YW-211)
文摘The mineralogical and micromorphological characteristics of Si-Fe-Mn oxyhydroxides from the dacite-hosted PACMANUS hydrothermal field were analyzed.The samples are poorly crystallized Si-Fe-Mn oxyhydroxides with minor birnessite, todorokite, nontronite, goethite, and opal-A.There are some microtextures which are rather like fossil microbes such as the filamentous silica and the hollow pipes.Flakes of nontronite crystals are found either forming a honeycomb texture or distrib- uted on the surface of the hollow pipes.Nontronite is the product precipitated from low-temperature hydrothermal fluids, and microbes may play a role in its formation.Si-Fe-Mn oxyhydroxides have two kinds of nuclei: Si-Mn nuclei and Si nuclei, both enveloped by the similar Si-Fe outer layer, existing in the rod-shaped oxyhydroxide and spheroidal oxyhydroxide, respectively.In the Si-Mn nuclei, the concentration of SiO2 is between 39.32 wt% and 86.31 wt%, and MnO concentration is between 4.97 wt% and 27.01 wt%, but Fe2O3 concentration is very low (0.54 wt%-3.43 wt%).In the Si nucleus the concentration of SiO2 is 90.17 wt%, but concentration of MnO and Fe2O3 are low, with 0.06 wt% and 3.47 wt%, respectively.The formation of the Si-Mn nucleus is closely related to microbes, whereas the Si nucleus is of inorganic origin.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11074293,51021061 and 50831006)
文摘The coexistence of magnetic ordering and ferroelectricity, ing on the origin of ferroelectricity, multiferroic materials known as multiferroics, has drawn a lot of research effort. Depend can be classified into different groups. In this paper, we review re cent progress in the field of multiferroics induced by different forms of charge ordering. In addition to a general description of charge order and electronic ferroelectricity, we focus on two specific systems： （1） charge order with frustration in RFe2O4 （R=Lu, Yb） system; （2） charge ordered perovskite manganites of the type （R1-xCax）MnO3 （R=La, Pr）. The charge ordering can be tuned by external electric fields, which results in pronounced magnetoelectric effects and strong dielectric tunability. Other materials and possible candidates with charge order induced multiferroics are also briefly summarized.
