The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadi...The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadium pentoxide.By adding Ca(OH)_(2) and ball milling,not only the V in the solution can be selectively precipitated,but also the leaching kinetics of the precipitate is significantly improved.The precipitation efficiency of V is 99.59%by adding Ca(OH)_(2) according to Ca/V molar ratio of 1.75:1 into chromium-containing vanadate solution and ball milling for 60 min at room temperature,while the content of Cr in the precipitate is 0.04%.The leaching rate of V reaches 99.35%by adding NaHCO_(3) into water according to NaHCO_(3)/V molar ratio of 2.74:1 to leach V from the precipitate with L/S ratio of 4:1 mL/g and stirring for 60 min at room temperature.The crystals of NH_(4)VO_(3) are obtained by adjusting the leaching solution pH to be 8.0 with CO2 and then adding NH_(4)HCO_(3) according to NH_(4)HCO_(3)/NaVO_(3) molar ratio of 1:1 and stirring for 8 h at room temperature.After filtration,the crystallized solution containing ammonia is reused to leach the precipitate of calcium vanadates,and the leaching efficiency of V is>99%after stirring for 1 h at room temperature.Finally,the product of V_(2)O_(5) with purity of 99.6%is obtained by calcining the crystals at 560℃ for 2 h.展开更多
A method to generate the dynamic moderate pressure dc glow discharge on the basis of electrolytic cathode in the form of aqueous solution of sodium bicarbonate NaHCO3 is described. Photo and video images of the discha...A method to generate the dynamic moderate pressure dc glow discharge on the basis of electrolytic cathode in the form of aqueous solution of sodium bicarbonate NaHCO3 is described. Photo and video images of the discharge are presented as well as the synchronized therewith “oscillograms” of current and voltage. Different phases of the discharge were discovered, one of which is a quasi-stationary glow discharge with the foamy cathode, was recorded for the first time. It was shown, that in this phase the discharge is supported by a so-called three-dimensional cathode spot, having the finite volume. The time-spatial diagram was plotted for the discharge. The Rayleigh-Taylor instability in the two-layered electrolytic cathode was recorded.展开更多
目的探讨奥美拉唑联合5%碳酸氢钠及糜蛋白酶治疗胃石症的临床疗效。方法选择2000年2月至2018年1月本院收治的38例胃石症患者,均予以40 mg奥美拉唑bid联合100 ml 5%碳酸氢钠tid口服或胃管注入及糜蛋白酶4 000单位qid口服,患者治疗满1周...目的探讨奥美拉唑联合5%碳酸氢钠及糜蛋白酶治疗胃石症的临床疗效。方法选择2000年2月至2018年1月本院收治的38例胃石症患者,均予以40 mg奥美拉唑bid联合100 ml 5%碳酸氢钠tid口服或胃管注入及糜蛋白酶4 000单位qid口服,患者治疗满1周或症状缓解后复查胃镜评估疗效。结果应用奥美拉唑联合5%碳酸氢钠及糜蛋白酶治疗,38例患者中有34例患者复查胃镜胃石消失。未见肠梗阻并发症及死亡病例。结论奥美拉唑联合5%碳酸氢钠及糜蛋白酶治疗胃石症效果确切,安全性高。展开更多
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(51974369)the Postgraduate Research Innovation Project of Central South University,China(2019zzts244).
文摘The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadium pentoxide.By adding Ca(OH)_(2) and ball milling,not only the V in the solution can be selectively precipitated,but also the leaching kinetics of the precipitate is significantly improved.The precipitation efficiency of V is 99.59%by adding Ca(OH)_(2) according to Ca/V molar ratio of 1.75:1 into chromium-containing vanadate solution and ball milling for 60 min at room temperature,while the content of Cr in the precipitate is 0.04%.The leaching rate of V reaches 99.35%by adding NaHCO_(3) into water according to NaHCO_(3)/V molar ratio of 2.74:1 to leach V from the precipitate with L/S ratio of 4:1 mL/g and stirring for 60 min at room temperature.The crystals of NH_(4)VO_(3) are obtained by adjusting the leaching solution pH to be 8.0 with CO2 and then adding NH_(4)HCO_(3) according to NH_(4)HCO_(3)/NaVO_(3) molar ratio of 1:1 and stirring for 8 h at room temperature.After filtration,the crystallized solution containing ammonia is reused to leach the precipitate of calcium vanadates,and the leaching efficiency of V is>99%after stirring for 1 h at room temperature.Finally,the product of V_(2)O_(5) with purity of 99.6%is obtained by calcining the crystals at 560℃ for 2 h.
文摘A method to generate the dynamic moderate pressure dc glow discharge on the basis of electrolytic cathode in the form of aqueous solution of sodium bicarbonate NaHCO3 is described. Photo and video images of the discharge are presented as well as the synchronized therewith “oscillograms” of current and voltage. Different phases of the discharge were discovered, one of which is a quasi-stationary glow discharge with the foamy cathode, was recorded for the first time. It was shown, that in this phase the discharge is supported by a so-called three-dimensional cathode spot, having the finite volume. The time-spatial diagram was plotted for the discharge. The Rayleigh-Taylor instability in the two-layered electrolytic cathode was recorded.
文摘目的探讨奥美拉唑联合5%碳酸氢钠及糜蛋白酶治疗胃石症的临床疗效。方法选择2000年2月至2018年1月本院收治的38例胃石症患者,均予以40 mg奥美拉唑bid联合100 ml 5%碳酸氢钠tid口服或胃管注入及糜蛋白酶4 000单位qid口服,患者治疗满1周或症状缓解后复查胃镜评估疗效。结果应用奥美拉唑联合5%碳酸氢钠及糜蛋白酶治疗,38例患者中有34例患者复查胃镜胃石消失。未见肠梗阻并发症及死亡病例。结论奥美拉唑联合5%碳酸氢钠及糜蛋白酶治疗胃石症效果确切,安全性高。
