As an alternative reductant for fossil fuel in the future,straw-type biomass contributes to emission reduction and green utilization in the suspension roasting process.In this study,the influences of the roasting time...As an alternative reductant for fossil fuel in the future,straw-type biomass contributes to emission reduction and green utilization in the suspension roasting process.In this study,the influences of the roasting time,roasting temperature and dose of straw-type biomass after suspension magnetization roasting(SMR) and separation were investigated.The optimal conditions were determined to be a roasting time of 7.5 min with a straw-type biomass dose of 20 wt% and a roasting temperature of 800℃ in which an iron grade of 71.07% and recovery of 94.17% were obtained for the iron concentrate.The maximum saturation magnetization under optimal conditions was 35.05 A·m^(2)·g^(-1),and the gaseous regulation of the biomass revealed that cumulative reducing gas volume was 293.93 mL at the optimal roasting time of450 s.The transformation of hematite to magnetite was detected by X-ray diffraction(XRD).During microstructure evolution,the outer layer consisting of fissures and tiny holes continuously deepened toward the core.展开更多
Potassium (K) leaching is detrimental to the maintenance of sustainable arable soil K fertility,especially in low-K fixation soils.It is not known whether the application of inorganic fertilizers with lower K mobility...Potassium (K) leaching is detrimental to the maintenance of sustainable arable soil K fertility,especially in low-K fixation soils.It is not known whether the application of inorganic fertilizers with lower K mobility or crop straw can reduce potential K leaching in low-K fixation arable soils.The potential K leaching of 14 representative arable soils with different K fixation capacities in China was evaluated with or without the addition of K under two rainfall intensities (90 and 225 mm),and then potential K leaching was assessed in relation to five K sources (KCl,K_(2)SO_(4),KH_(2)PO_(4),maize (Zea mays L.) straw,and rice (Oryza sativa L.) straw).Without K addition,K leaching mainly occurred in sandy soils at 90 mm of rainfall and in soils with greater organic matter at225 mm of rainfall.With K addition,the leaching percentage of exogenous K ranged from 0.6%to 11.6%at 90 mm of rainfall and 1.2%to 21.2%at 225 mm of rainfall.The greatest K leaching occurred in soils with fewer K-bearing minerals and lower pH at both rainfall intensities.In most cases,KH_(2)PO_(4),which has lower K mobility,markedly reduced K leaching in both high-and low-K leaching soils at the two rainfall intensities.Maize and rice straw reduced K leaching only in soils with high K leaching,regardless of rainfall amount,whereas more K was leached in soils with lower K leaching at high rainfall intensity.In conclusion,KH_(2)PO_(4) and straw should be preferred for reducing K leaching in low-K fixation arable soils.展开更多
Due to the arid climate,flat terrain,certain irrigation sources and high popularization of mechanical harvest in Hexi Irrigation Area of Gansu Province,the widely adopted half film-flat-mulching for corn cultivation f...Due to the arid climate,flat terrain,certain irrigation sources and high popularization of mechanical harvest in Hexi Irrigation Area of Gansu Province,the widely adopted half film-flat-mulching for corn cultivation faces serious adverse situations,such as high soil compactness,strong film-soil adhesion,significant straw stubble and thick covering accumulation on film.Therefore,a new kind of segmented combination upper-side-discharge straw-returning and bundle self-unloading integrated corn residual film recycling machine was proposed.The scheme was characterized by small volume,low resistance,low complexity and film-impurities twice separation.It is constructed based on the concept of module subsection combination.It was composed of film surface straw cleaning device and the followed residual film recycling machine,in terms of function,any usage requirements of separate and joint operations can be satisfied.The film surface straw cleaning device is responsible for the removal of vertical corn straw and ground covering beyond the film.Although its stubble cutter roller obtuse-angle Lshaped blades paired single-helix arrangement is simple,it runs smoothly and the straw crushing effect is good enough.The layout that upper-side-discharge straw-returning cross-range screw conveyor auger is back and beyond the stubble cutter roller,eliminates the common connecting transportation mechanism between crushing and straw-returning section,so that,the system structure can be optimized and the efficiency has been significantly improved.The integrated residual film recycling machine is composed of triangular pyramid arc two-stage wing(TPATSW)type film lifting shovel,rod-tooth-belt type film-impurities separation device and semi-enclosed shaftless bundle film collector.Among them,TPATSW type film lifting shovel has good corn root whisker cutting effect,low soil contact resistance and small soil congestion area,but its ability to lift film is strong,more importantly,the special segmented configuration of shovel handle and the bo展开更多
基金the financial support provided to this work by the National Natural Science Foundation of China (No. 52022019)。
文摘As an alternative reductant for fossil fuel in the future,straw-type biomass contributes to emission reduction and green utilization in the suspension roasting process.In this study,the influences of the roasting time,roasting temperature and dose of straw-type biomass after suspension magnetization roasting(SMR) and separation were investigated.The optimal conditions were determined to be a roasting time of 7.5 min with a straw-type biomass dose of 20 wt% and a roasting temperature of 800℃ in which an iron grade of 71.07% and recovery of 94.17% were obtained for the iron concentrate.The maximum saturation magnetization under optimal conditions was 35.05 A·m^(2)·g^(-1),and the gaseous regulation of the biomass revealed that cumulative reducing gas volume was 293.93 mL at the optimal roasting time of450 s.The transformation of hematite to magnetite was detected by X-ray diffraction(XRD).During microstructure evolution,the outer layer consisting of fissures and tiny holes continuously deepened toward the core.
基金supported by the National Key Research and Development Program of China (No. 2018YFD0200901)the National Natural Science Foundation for Young Scientists of China (No. 41907075)。
文摘Potassium (K) leaching is detrimental to the maintenance of sustainable arable soil K fertility,especially in low-K fixation soils.It is not known whether the application of inorganic fertilizers with lower K mobility or crop straw can reduce potential K leaching in low-K fixation arable soils.The potential K leaching of 14 representative arable soils with different K fixation capacities in China was evaluated with or without the addition of K under two rainfall intensities (90 and 225 mm),and then potential K leaching was assessed in relation to five K sources (KCl,K_(2)SO_(4),KH_(2)PO_(4),maize (Zea mays L.) straw,and rice (Oryza sativa L.) straw).Without K addition,K leaching mainly occurred in sandy soils at 90 mm of rainfall and in soils with greater organic matter at225 mm of rainfall.With K addition,the leaching percentage of exogenous K ranged from 0.6%to 11.6%at 90 mm of rainfall and 1.2%to 21.2%at 225 mm of rainfall.The greatest K leaching occurred in soils with fewer K-bearing minerals and lower pH at both rainfall intensities.In most cases,KH_(2)PO_(4),which has lower K mobility,markedly reduced K leaching in both high-and low-K leaching soils at the two rainfall intensities.Maize and rice straw reduced K leaching only in soils with high K leaching,regardless of rainfall amount,whereas more K was leached in soils with lower K leaching at high rainfall intensity.In conclusion,KH_(2)PO_(4) and straw should be preferred for reducing K leaching in low-K fixation arable soils.
基金the support of the Gansu Educational Science and Technology Innovation Project(Grant No.2021CYZC-25)the Gansu Science and Technology Planning Project(Grant No.21CX6NA081)+1 种基金the National Natural Science Foundation of China(Grant No.52165028)the Key Scientific and Technological Program of Gansu Province(Grant No.22ZD6NA046).
文摘Due to the arid climate,flat terrain,certain irrigation sources and high popularization of mechanical harvest in Hexi Irrigation Area of Gansu Province,the widely adopted half film-flat-mulching for corn cultivation faces serious adverse situations,such as high soil compactness,strong film-soil adhesion,significant straw stubble and thick covering accumulation on film.Therefore,a new kind of segmented combination upper-side-discharge straw-returning and bundle self-unloading integrated corn residual film recycling machine was proposed.The scheme was characterized by small volume,low resistance,low complexity and film-impurities twice separation.It is constructed based on the concept of module subsection combination.It was composed of film surface straw cleaning device and the followed residual film recycling machine,in terms of function,any usage requirements of separate and joint operations can be satisfied.The film surface straw cleaning device is responsible for the removal of vertical corn straw and ground covering beyond the film.Although its stubble cutter roller obtuse-angle Lshaped blades paired single-helix arrangement is simple,it runs smoothly and the straw crushing effect is good enough.The layout that upper-side-discharge straw-returning cross-range screw conveyor auger is back and beyond the stubble cutter roller,eliminates the common connecting transportation mechanism between crushing and straw-returning section,so that,the system structure can be optimized and the efficiency has been significantly improved.The integrated residual film recycling machine is composed of triangular pyramid arc two-stage wing(TPATSW)type film lifting shovel,rod-tooth-belt type film-impurities separation device and semi-enclosed shaftless bundle film collector.Among them,TPATSW type film lifting shovel has good corn root whisker cutting effect,low soil contact resistance and small soil congestion area,but its ability to lift film is strong,more importantly,the special segmented configuration of shovel handle and the bo
