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| 1 | Flow-field analysis of a continuous gas-solid separation fluidized bed equipped with a moving scraper显示文摘Continuous gas-solid separation fluidized beds are one of the most widely used practical operation units for the dry separation of coal in China,particularly in Northwest China,and they can effectively promote the efficient and clean utilization of raw coal.In a continuous gas-solid separation fluidized bed,the bed flow field is the concrete manifestation of the fluidization characteristics.However,the complexity of the flow field increases under the action of a moving scraper.In this study,a combination of computational fluid dynamics(CFD)simulations and experimental measurements was used to study the changes in the flow field of a fluidized bed.The results showed that when the scraper moved,the local flow field(mainly characterized by the movement of medium particles)near the scraper was affected not only by the common airflow or bubbles,but also by the lateral driving force of the scraper.When the scraper speed was v_(l)<6.0 cm/s,it reduced the frequency of the formation of large bubbles and alleviated the random fluctuation of the nearby particle collision stress signals,which improved the fluidization stability of the bed.Additionally,the movement of the scraper affected the global flow field.The flow field shifted to the right near the scraper,with the direction of the scraper movement,while the flow field exhibited a leftward trend on the surface of the bed,accompanied by some vortices,in the middle and lower parts of the bed.Additionally,the critical height of the area,directly affected by the scraper,increased from 52 to 54 mm with an increase in its operating speed from v_(l)=2.96 cm/s to v_(l)=4.44 cm/s,respectively.This provides a theoretical basis for further understanding the hydrodynamic characteristics of fluidized beds. | Bo Lv Xiaowei Deng Chaojun Fang Xiangnan Zhu | 2021 | Particuology2021，19，4： | 1 |
| 2 | Chalcocite(bio)hydrometallurgy-current state,mechanism,and future directions:A review显示文摘There has been a strong interest in technologies suited for mining and processing of low-grade ores because of the rapid depletion of mineral resources in the world.In most cases,the extraction of copper from such raw materials is achieved by applying the leaching procedures.However,its low extraction efficiency and the long extraction period limit its large-scale commercial applications in copper recovery,even though bioleaching has been widely employed commercially for heap and dump bioleaching of secondary copper sulfide ores.Overcoming the technical challenges requires a better understanding of leaching kinetics and on-site microbial activities.Herein,this paper reviews the current status of main commercial biomining operations around the world,identifies factors that affect chalcocite dissolution both in chemical leaching and bioleaching,summarizes the related kinetic research,and concludes with a discussion of two on-site chalcocite heap leaching practices.Further,the challenges and innovations for the future development of chalcocite hydrometallurgy are presented in the end. | Shichao Yu Rui Liao Baojun Yang Chaojun Fang Zhentang Wang Yuling Liu Baiqiang Wu Jun Wang Guanzhou Qiu | 2022 | Chinese Journal of Chemical Engineering2022，35，1： | 1 |
| 3 | Motion characteristics and density separation of fine coal in an inflatable-inclined liquid-solid fluidized bed显示文摘To improve the adaptability of fluidized beds for fine coal separation,a new type of liquid-solid fluidized bed was constructed,i.e.,the inflatable-inclined liquid-solid fluidized bed(IILSFB).A combination of simulation analysis and separation experiments was used to analyze the fluidization characteristics and separation performance of the IILSFB.The results showed that there was upflow and downflow in the fluidized bed.The upflow was mainly composed of water flow,followed by light and heavy particles;on the other hand,the downflow was caused by the backflow of heavy particles that settled at the inclined section.In addition,the light particles that settled at the inclined section could return to the rising water flow under the action of secondary airflow.As the water velocity,separation time,and secondary gas velocity increased,the comprehensive separation efficiency of fine coal in the fluidized bed improved,while the value decreased as the feed quantity increased.This also indicated the order of importance for these four factors,i.e.,water velocity,separation time,feed quantity,and secondary gas velocity,on fluidisation.Furthermore,the comprehensive separation efficiency of 0.1-1 mm fine coal varied significantly with various factors,while that of∼0.1 mm and 1-3 mm fine coal was always at a low value.In the latter case,the classification process of the size fraction was significantly better than the separation process in the fluidized bed.Under optimal working conditions,an IILSFB was used to separate the fine coal(0.1-1 mm).The yield of clean coal was 37.95% with an ash content of 12.11%,and the possible error was 0.085 g/cm^(3),indicating that the IILSFB had good separation performance for 0.1-1 mm fine coal. | Bo Lv Bobing Dong Xiaowei Deng Chaojun Fang | 2021 | Particuology2021，19，5： | 1 |
| 4 | Climate-Vegetation Coverage Interactions in the Hengduan Mountains Area, Southeastern Tibetan Plateau, and Their Downstream Effects显示文摘Little is known about the mechanism of climate-vegetation coverage coupled changes in the Tibetan Plateau(TP)region,which is the most climatically sensitive and ecologically fragile region with the highest terrain in the world.This study,using multisource datasets(including satellite data and meteorological observations and reanalysis data)revealed the mutual feedback mechanisms between changes in climate(temperature and precipitation)and vegetation coverage in recent decades in the Hengduan Mountains Area(HMA)of the southeastern TP and their influences on climate in the downstream region,the Sichuan Basin(SCB).There is mutual facilitation between rising air temperature and increasing vegetation coverage in the HMA,which is most significant during winter,and then during spring,but insignificant during summer and autumn.Rising temperature significantly enhances local vegetation coverage,and vegetation greening in turn heats the atmosphere via enhancing net heat flux from the surface to the atmosphere.The atmospheric heating anomaly over the HMA thickens the atmospheric column and increases upper air pressure.The high pressure anomaly disperses downstream via the westerly flow,expands across the SCB,and eventually increases the SCB temperature.This effect lasts from winter to the following spring,which may cause the maximum increasing trend of the SCB temperature and vegetation coverage in spring.These results are helpful for estimating future trends in climate and eco-environmental variations in the HMA and SCB under warming scenarios,as well as seasonal forecasting based on the connection between the HMA eco-environment and SCB climate. | Congxi FANG Jinlei CHEN Chaojun OUYANG Lu WANG Changfeng SUN Quan ZHANG Jun WEN | 2024 | Advances in Atmospheric Sciences2024，41，4： | 0 |
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