In the preparation of magnesium by Pidgeon process,the phenomenon slag pellets sticking on the wall of reduction pot always appear,and the glaze sticking on the inner wall of the reduction pot is difficult to remove.T...In the preparation of magnesium by Pidgeon process,the phenomenon slag pellets sticking on the wall of reduction pot always appear,and the glaze sticking on the inner wall of the reduction pot is difficult to remove.The mechanism of this phenomenon is studied in this work by X-ray fluorescence spectrometer(XRF)measurement,electron probe microanalyzer scanning(EPMA)analysis,differential scanning calorimetry(DSC)analysis,and thermodynamic calculations.The main components of the glaze are MgO,Ca_(12)Al_(14)F_(2)O_(32),CaF_(2),CaO,and a small amount of Ca_(4)Si_(2)O_(7)F_(2).The solid-liquid transition temperature of Ca_(12)Al_(14)F_(2)O_(32)and CaF_(2)is close to the production temperature of Pidgeon process,which leads to the bonding between the slag pellets and the pot wall.The loss of CaF_(2)in glaze layer will reduce the total amount of liquid phase and increase the temperature at which Ca_(12)Al_(14)F_(2)O_(32)is completely transformed into liquid phase,which causes glaze layer sticking on the inner wall of the reduction pot.展开更多
With the fast development of the application of magnesium based alloys,the demand for primary magnesium is increasing dramatically all over the world.The Pidgeon process is the most widely used process for producing m...With the fast development of the application of magnesium based alloys,the demand for primary magnesium is increasing dramatically all over the world.The Pidgeon process is the most widely used process for producing magnesium in China,but suffers from problems such as high energy,resource consumption and environmental pollution.While the process of vacuum carbothermal reduction to produce magnesium(VCTRM)has attracted more and more attention as its advantages,but it has not been well-practiced in industrial applications and there also is no comprehensive and quantitative analysis of this process.This study quantified the flows of resource and energy for the Pidgeon process and the VCTRM process,then compared and analyzed these two processes with each other from three aspects.The VCTRM process results in 63.14%and 69.16%lower of non-renewable mineral resources and energy consumptions when compared to the Pidgeon process,respectively.Moreover,the low energy consumption(2.675 tce vs.8.681 tce)and material to magnesium ratio(2.953:1 vs.6.429:1)of the VCTRM process,which lead to lower greenhouse gas(GHG)emissions(8.777 t vs.26.337 t)and solid waste generation(0.522 t vs.5.465 t)with a decrease of 66.67%and 90.45%,respectively.Results indicate that the VCTRM process is a more environmentally friendly process for magnesium production with high efficiency but low cost and low pollution,and it shows a good potential to be industrialized in the future after solving the bottleneck problem of the reverse reaction.展开更多
Based on the practice of magnesium production in China, a quantitative evaluation of the environment impact was carried out according to the theory and framework of life cycle assessment(LCA) study. The major gaseous ...Based on the practice of magnesium production in China, a quantitative evaluation of the environment impact was carried out according to the theory and framework of life cycle assessment(LCA) study. The major gaseous pollutants including CO2, SO2, NOx, CH4, HF and particulates were calculated. The accumulative environmental performances of different energy use strategies and the characterization results, including abiotic depletion potential(ADP), global warming potential(GWP), acidification potential(AP) and human-toxicity potential(HTP) were compared. The results show that the direct emission of fuel combustion in the process is the major contributor to the pollutants emission of magnesium production. Global warming potential and acidification potential make the main contribution to the accumulative environmental impact. The different fuel use strategies in the practice of magnesium production cause much different impacts on the environmental performance. The accumulative environmental impact of coal burned directly is the highest, and that of producer-gas comes to the next, while that of coke-oven gas is the lowest.展开更多
基金funded by the China Postdoctoral Sci-ence Foundation(Grant No.2020M682337)Certificate of Postdoctoral Research Grant in Henan Province(Grant No.201903011)National Key Research and Development Program of China(Grant Nos.2016YFB0301001 and 2016YFB0301101).
文摘In the preparation of magnesium by Pidgeon process,the phenomenon slag pellets sticking on the wall of reduction pot always appear,and the glaze sticking on the inner wall of the reduction pot is difficult to remove.The mechanism of this phenomenon is studied in this work by X-ray fluorescence spectrometer(XRF)measurement,electron probe microanalyzer scanning(EPMA)analysis,differential scanning calorimetry(DSC)analysis,and thermodynamic calculations.The main components of the glaze are MgO,Ca_(12)Al_(14)F_(2)O_(32),CaF_(2),CaO,and a small amount of Ca_(4)Si_(2)O_(7)F_(2).The solid-liquid transition temperature of Ca_(12)Al_(14)F_(2)O_(32)and CaF_(2)is close to the production temperature of Pidgeon process,which leads to the bonding between the slag pellets and the pot wall.The loss of CaF_(2)in glaze layer will reduce the total amount of liquid phase and increase the temperature at which Ca_(12)Al_(14)F_(2)O_(32)is completely transformed into liquid phase,which causes glaze layer sticking on the inner wall of the reduction pot.
基金the Yunnan Ten Thousand Talents Plan Industrial Technology Champion Project Foundation of China(No.YNWR-CYJS-2018-015)Basic Research Project of Yunnan Province(No.2019FB080).
文摘With the fast development of the application of magnesium based alloys,the demand for primary magnesium is increasing dramatically all over the world.The Pidgeon process is the most widely used process for producing magnesium in China,but suffers from problems such as high energy,resource consumption and environmental pollution.While the process of vacuum carbothermal reduction to produce magnesium(VCTRM)has attracted more and more attention as its advantages,but it has not been well-practiced in industrial applications and there also is no comprehensive and quantitative analysis of this process.This study quantified the flows of resource and energy for the Pidgeon process and the VCTRM process,then compared and analyzed these two processes with each other from three aspects.The VCTRM process results in 63.14%and 69.16%lower of non-renewable mineral resources and energy consumptions when compared to the Pidgeon process,respectively.Moreover,the low energy consumption(2.675 tce vs.8.681 tce)and material to magnesium ratio(2.953:1 vs.6.429:1)of the VCTRM process,which lead to lower greenhouse gas(GHG)emissions(8.777 t vs.26.337 t)and solid waste generation(0.522 t vs.5.465 t)with a decrease of 66.67%and 90.45%,respectively.Results indicate that the VCTRM process is a more environmentally friendly process for magnesium production with high efficiency but low cost and low pollution,and it shows a good potential to be industrialized in the future after solving the bottleneck problem of the reverse reaction.
基金Project(50525413) supported by the National Natural Science Foundation of ChinaProject(2006BAE04B09-6) supported by National Key Technology R&D Program
文摘Based on the practice of magnesium production in China, a quantitative evaluation of the environment impact was carried out according to the theory and framework of life cycle assessment(LCA) study. The major gaseous pollutants including CO2, SO2, NOx, CH4, HF and particulates were calculated. The accumulative environmental performances of different energy use strategies and the characterization results, including abiotic depletion potential(ADP), global warming potential(GWP), acidification potential(AP) and human-toxicity potential(HTP) were compared. The results show that the direct emission of fuel combustion in the process is the major contributor to the pollutants emission of magnesium production. Global warming potential and acidification potential make the main contribution to the accumulative environmental impact. The different fuel use strategies in the practice of magnesium production cause much different impacts on the environmental performance. The accumulative environmental impact of coal burned directly is the highest, and that of producer-gas comes to the next, while that of coke-oven gas is the lowest.
基金supported by the National Key Research and Development Program of China(No.2021YFC29003205)the National Natural Science Foundation of China(Nos.21878045,51504058)+1 种基金the Fundamental Research Funds for the Central Universities,China(No.N2225019)Natural Science Foundation of Liaoning Province,China(No.2022-MS-106)。
