Ultra fine grinding of the plant tailings of a refractory silver ore was studied using a laboratory type vertical stirred media mill. Preliminary tests confirmed that ultra fine grinding substantially improves the ext...Ultra fine grinding of the plant tailings of a refractory silver ore was studied using a laboratory type vertical stirred media mill. Preliminary tests confirmed that ultra fine grinding substantially improves the extraction of silver from the tailings in cyanide leaching （i.e. 36% Ag extraction rate from the as-received tailings with d80 of 100 μm, c.f. 84% extraction rate after ultra fine grinding of the tailings with ds0 of 1.2 pro）. In the ultra fine grinding tests, the effects of ball diameter （2-4.5 mm）, stirring speed （200-800 r/m/n） and ball charge ratio （50%-80%） on the fineness of grind （ds0, ~tm） were investigated through a Box-Behnken design. Increasing stirrer speed and ball charge ratio decreased fineness of grind while larger balls resulted in the coarser products. The tests demonstrated that a fineness of grind less than 5 μm can be achieved under suitable conditions. Analysis of stress intensity indicated an optimum range of stress intensity of （0.8-2）× 10^- 3 μm for all power inputs.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 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 extrartion of aluminum from coal mining waste(CMW) is an important industrial process.The two major problems in applications are low aluminum dissolution efficiency and high iron content in the raw material,which ...The extrartion of aluminum from coal mining waste(CMW) is an important industrial process.The two major problems in applications are low aluminum dissolution efficiency and high iron content in the raw material,which affect the quantity and quality of products.To improve the aluminum recovery process,the leaching kinetics of CMW with hydrochloric acid was studied.A shrinking core model was used to investigate aluminum and iron dissolution kinetics.Based on the kinetic characteristics,a process for recovering aluminum was proposed and tested experimentally.It is found that the aluminum leaching reaction is controlled by surface reaction at low temperatures(40-80℃) and by diffusion process at higher temperatures(90-106℃).The iron dissolution process is dominated by surface reaction at 40-100℃.The results show that iron could be dissolved or separated by concentrated hydrochloric acid.Fine grinding will improve aluminum dissolution significantly.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Ultra fine grinding of the plant tailings of a refractory silver ore was studied using a laboratory type vertical stirred media mill. Preliminary tests confirmed that ultra fine grinding substantially improves the extraction of silver from the tailings in cyanide leaching （i.e. 36% Ag extraction rate from the as-received tailings with d80 of 100 μm, c.f. 84% extraction rate after ultra fine grinding of the tailings with ds0 of 1.2 pro）. In the ultra fine grinding tests, the effects of ball diameter （2-4.5 mm）, stirring speed （200-800 r/m/n） and ball charge ratio （50%-80%） on the fineness of grind （ds0, ~tm） were investigated through a Box-Behnken design. Increasing stirrer speed and ball charge ratio decreased fineness of grind while larger balls resulted in the coarser products. The tests demonstrated that a fineness of grind less than 5 μm can be achieved under suitable conditions. Analysis of stress intensity indicated an optimum range of stress intensity of （0.8-2）× 10^- 3 μm for all power inputs.
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 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.
基金Supported by the National High Technology Research and Development Program of China(2011AA06A103)the National Natural Science Foundation of China(21306109)
文摘The extrartion of aluminum from coal mining waste(CMW) is an important industrial process.The two major problems in applications are low aluminum dissolution efficiency and high iron content in the raw material,which affect the quantity and quality of products.To improve the aluminum recovery process,the leaching kinetics of CMW with hydrochloric acid was studied.A shrinking core model was used to investigate aluminum and iron dissolution kinetics.Based on the kinetic characteristics,a process for recovering aluminum was proposed and tested experimentally.It is found that the aluminum leaching reaction is controlled by surface reaction at low temperatures(40-80℃) and by diffusion process at higher temperatures(90-106℃).The iron dissolution process is dominated by surface reaction at 40-100℃.The results show that iron could be dissolved or separated by concentrated hydrochloric acid.Fine grinding will improve aluminum dissolution significantly.
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.
