Electrostatic separation is one of the mineral processing methods based on mineral conductivity.This method has some significant problems such as being sensitive to humidity,high middling product,and impurity of non-c...Electrostatic separation is one of the mineral processing methods based on mineral conductivity.This method has some significant problems such as being sensitive to humidity,high middling product,and impurity of non-conductive minerals.In this study,a new pretreatment method was proposed for the separation of zircon from quartz before electrostatic separation to solve these disadvantages.In this regard,two stages of pretreatment were applied which involved using collector of sodium dodecyl sulfate(SDS)for adjusting wettability of the zircon surface and spraying electrolyte aqueous solution to increase conductivity of the quartz surface.The effects of important parameters including pH,collector concentration,conditioning time,and concentration and type of electrolyte on the process efficiency were evaluated.The results showed that the optimal conditions of high-tension electrical separation were pH of 4,SDS concentration of 1×10-4 mol/L,conditioning time of 4 min and NaCl as an electrolyte with concentration of 4.27 mol/L.Separation efficiency of 95.12% was achieved in optimum conditions.This pretreatment method can be successfully used before high-tension electrical separation to separate the conductive or non-conductive minerals with various compositions.展开更多
It is known that ore containing cassiterite （SnO2） has been our most important source of tin since antiquity and its successful separation continuously pose problems to mineral processors. The situation is more pron...It is known that ore containing cassiterite （SnO2） has been our most important source of tin since antiquity and its successful separation continuously pose problems to mineral processors. The situation is more pronounced since the depletion of the more easily recoverable alluvial reserves forces us to work with the more complex deposits such as hardrock cassiterite ores. In order to understand more about the challenges in processing complex tin ore deposits, a metasedimentary rock ore sample from a mine in Malaysia was used in this study. Chemical analysis by wet method shows that SnO2 content in the sample was 2.86%, while for mineralogical analysis, the x-ray diffractogram （XRD） of the sample had identified that besides cassiterite, the sample also contained minerals such as quartz （SiO2） and clinochlore. Furthermore, the FESEM （field emission scanning electron microscope） micrograph analysis carried out on a polish section of the sample indicated that the fine cassiterite particles （approximately 80 ~tm） were found to be disseminated in the quartz minerals. Prior to the separation processes, grindability studies were carried-out on crushed samples to liberate the cassiterite from other gangue minerals and at the same time, avoid producing high percentage of fines. For the separation of tin from gangue minerals on the ground samples, two stages of gravity separations by shaking tables were carried out. The first stage was run on ground samples and for the second stage, the middling product from the first stage was re-tabled. Magnetic separation process on Concentrate 1 （stage 1） and Concentrate 2 （stage 2） products from the shaking table increased the grade of SnO2 to 46.85% and 61.90% respectively （as a non-magnetic products）. Further concentration process of these non-magnetic products by high tension separator, increased the grade of SnO2 from 85.05% to 98.77%.展开更多
Membrane tension plays a significant role in many cellular processes including cell adhesion, migration and spreading. Despite the importance of membrane tension, it remains difficult to measure in vivo. Recently, the...Membrane tension plays a significant role in many cellular processes including cell adhesion, migration and spreading. Despite the importance of membrane tension, it remains difficult to measure in vivo. Recently, the development of non-invasive fluorescent probes have made great progress, especially excitedstate deplanarization in molecular rotors has been applied to image membrane tension in living cells.Nevertheless, an intrinsic limitation of such kind of probe is that they depend on the lipid packing, and how the lipid packing responds to the membrane tension change remains unclear. Therefore, in this work,we used a polarity-sensitive membrane probe to investigate the possible response mechanism of lipid packing to the change of membrane tension that was regulated by osmotic shocks. The results showed that an increase in membrane tension could stretch the lipids apart with large displacements, and this change was not homogeneous on the whole membrane, instead, increase of membrane tension induced phase separation.展开更多
文摘Electrostatic separation is one of the mineral processing methods based on mineral conductivity.This method has some significant problems such as being sensitive to humidity,high middling product,and impurity of non-conductive minerals.In this study,a new pretreatment method was proposed for the separation of zircon from quartz before electrostatic separation to solve these disadvantages.In this regard,two stages of pretreatment were applied which involved using collector of sodium dodecyl sulfate(SDS)for adjusting wettability of the zircon surface and spraying electrolyte aqueous solution to increase conductivity of the quartz surface.The effects of important parameters including pH,collector concentration,conditioning time,and concentration and type of electrolyte on the process efficiency were evaluated.The results showed that the optimal conditions of high-tension electrical separation were pH of 4,SDS concentration of 1×10-4 mol/L,conditioning time of 4 min and NaCl as an electrolyte with concentration of 4.27 mol/L.Separation efficiency of 95.12% was achieved in optimum conditions.This pretreatment method can be successfully used before high-tension electrical separation to separate the conductive or non-conductive minerals with various compositions.
基金the financial supports from the National Natural Science Foundation of China(Nos.51904351,51620105013,U20A20273)the National Key R&D Program of China(No.2019YFC1907400)+2 种基金the Science and Technology Innovation Program of Hunan Province,China(No.2021RC3005)the Major Technological Innovation Projects of Shandong Province,China(No.2019JZZY010404)the Innovation Driven Program of Central South University,China(No.2020CX028)。
文摘It is known that ore containing cassiterite （SnO2） has been our most important source of tin since antiquity and its successful separation continuously pose problems to mineral processors. The situation is more pronounced since the depletion of the more easily recoverable alluvial reserves forces us to work with the more complex deposits such as hardrock cassiterite ores. In order to understand more about the challenges in processing complex tin ore deposits, a metasedimentary rock ore sample from a mine in Malaysia was used in this study. Chemical analysis by wet method shows that SnO2 content in the sample was 2.86%, while for mineralogical analysis, the x-ray diffractogram （XRD） of the sample had identified that besides cassiterite, the sample also contained minerals such as quartz （SiO2） and clinochlore. Furthermore, the FESEM （field emission scanning electron microscope） micrograph analysis carried out on a polish section of the sample indicated that the fine cassiterite particles （approximately 80 ~tm） were found to be disseminated in the quartz minerals. Prior to the separation processes, grindability studies were carried-out on crushed samples to liberate the cassiterite from other gangue minerals and at the same time, avoid producing high percentage of fines. For the separation of tin from gangue minerals on the ground samples, two stages of gravity separations by shaking tables were carried out. The first stage was run on ground samples and for the second stage, the middling product from the first stage was re-tabled. Magnetic separation process on Concentrate 1 （stage 1） and Concentrate 2 （stage 2） products from the shaking table increased the grade of SnO2 to 46.85% and 61.90% respectively （as a non-magnetic products）. Further concentration process of these non-magnetic products by high tension separator, increased the grade of SnO2 from 85.05% to 98.77%.
基金financially supported by Research and Development Program in Key Areas of Guangdong Province,China (No.2019B020209009)National Natural Science Foundation of China(Nos. 21727814, 22034005, 81872829)the China Postdoctoral Science Foundation (No. 2020M680502)。
文摘Membrane tension plays a significant role in many cellular processes including cell adhesion, migration and spreading. Despite the importance of membrane tension, it remains difficult to measure in vivo. Recently, the development of non-invasive fluorescent probes have made great progress, especially excitedstate deplanarization in molecular rotors has been applied to image membrane tension in living cells.Nevertheless, an intrinsic limitation of such kind of probe is that they depend on the lipid packing, and how the lipid packing responds to the membrane tension change remains unclear. Therefore, in this work,we used a polarity-sensitive membrane probe to investigate the possible response mechanism of lipid packing to the change of membrane tension that was regulated by osmotic shocks. The results showed that an increase in membrane tension could stretch the lipids apart with large displacements, and this change was not homogeneous on the whole membrane, instead, increase of membrane tension induced phase separation.
