The influence of mechanical activation on the leaching behaviour of scheelite was studied by means of fine grinding in an attritor and subsequently HCl leaching in presence of PO_4^(3-). Results showed that after fine...The influence of mechanical activation on the leaching behaviour of scheelite was studied by means of fine grinding in an attritor and subsequently HCl leaching in presence of PO_4^(3-). Results showed that after fine grinding in the attritor,the reaction rate of scheelite with HCl-Na_3PO_4 solution was remarkably increased,the extraction of W increased from about 8 to 99%.The IR spectra and X-ray diffraction analysis indicated that in addition to an enlargement of surface area the fine grinding action had made also changes of fine struc- ture and reactivity of solid surface,hence the leaching process of scheelite can be carried out under mild leaching conditions.展开更多
The performances of dry grinding fine cement (DFC) in grouting procedure were experimentally studied.The measurement of its fineness and simulated test for injectability showed that this DFC could be used to inject r...The performances of dry grinding fine cement (DFC) in grouting procedure were experimentally studied.The measurement of its fineness and simulated test for injectability showed that this DFC could be used to inject rock mass with micro fissure.In order to improve the grouting quality,the water cement ratio and discarding time of slurry should be controlled precisely.If the water cement ratio is over 2∶1 in slurry that is made from DFC,it is not suitable to grout.Finally,the influence of different mixing times on strength of hydrated cement made from the DFC is explained by microstructure analysis with SEM.展开更多
The precursor of Bi Pb Sr Ca Cu O superconductor was prepared by spray drying nitrate solution with nominal composition of Bi∶Pb∶Sr∶Ca∶Cu=1.84∶0.34∶1.91∶2.03∶3.06. Instrumentation of XRD、 DTA、 DTA TG...The precursor of Bi Pb Sr Ca Cu O superconductor was prepared by spray drying nitrate solution with nominal composition of Bi∶Pb∶Sr∶Ca∶Cu=1.84∶0.34∶1.91∶2.03∶3.06. Instrumentation of XRD、 DTA、 DTA TG、 FT IR and SEM was used for the evaluation of the influences of calcination and fine grinding on the synthesis of sperconducting materials with “high T c phase”. The experimental results indicated that the fine grinding with organic additives influenced the formation and the transition of the superconducting phase. The phase transition of the superconductor can be reduced greatly by means of high temperature grinding.展开更多
文摘The influence of mechanical activation on the leaching behaviour of scheelite was studied by means of fine grinding in an attritor and subsequently HCl leaching in presence of PO_4^(3-). Results showed that after fine grinding in the attritor,the reaction rate of scheelite with HCl-Na_3PO_4 solution was remarkably increased,the extraction of W increased from about 8 to 99%.The IR spectra and X-ray diffraction analysis indicated that in addition to an enlargement of surface area the fine grinding action had made also changes of fine struc- ture and reactivity of solid surface,hence the leaching process of scheelite can be carried out under mild leaching conditions.
文摘The performances of dry grinding fine cement (DFC) in grouting procedure were experimentally studied.The measurement of its fineness and simulated test for injectability showed that this DFC could be used to inject rock mass with micro fissure.In order to improve the grouting quality,the water cement ratio and discarding time of slurry should be controlled precisely.If the water cement ratio is over 2∶1 in slurry that is made from DFC,it is not suitable to grout.Finally,the influence of different mixing times on strength of hydrated cement made from the DFC is explained by microstructure analysis with SEM.
文摘The precursor of Bi Pb Sr Ca Cu O superconductor was prepared by spray drying nitrate solution with nominal composition of Bi∶Pb∶Sr∶Ca∶Cu=1.84∶0.34∶1.91∶2.03∶3.06. Instrumentation of XRD、 DTA、 DTA TG、 FT IR and SEM was used for the evaluation of the influences of calcination and fine grinding on the synthesis of sperconducting materials with “high T c phase”. The experimental results indicated that the fine grinding with organic additives influenced the formation and the transition of the superconducting phase. The phase transition of the superconductor can be reduced greatly by means of high temperature grinding.
