The leaching kinetics of low-grade copper ore with high-alkality gangues was studied in ammonia-ammonium sulphate solution.The main parameters,such as ammonia and ammonium sulphate concentrations,particle size,solid-t...The leaching kinetics of low-grade copper ore with high-alkality gangues was studied in ammonia-ammonium sulphate solution.The main parameters,such as ammonia and ammonium sulphate concentrations,particle size,solid-to-liquid ratio and reaction temperature,were chosen in the experiments.The results show that the increase of temperature,concentrations of ammonia and ammonium sulphate is propitious to the leaching rate of copper ore.The leaching rate increases with the decrease of particle size and solid-to-liquid ratio.The leaching rate is controlled by the diffusion through the ash layer and the activation energy is determined to be 25.54 kJ/mol.A semi-empirical equation was proposed to describe the leaching kinetics.展开更多
In order to clarify the unsteady flow fields at low flow-rate region with positive gradient on pressure-flow-rate curve,the experimental investigation was carried out at rotor inlet and outside of rotor blade tip with...In order to clarify the unsteady flow fields at low flow-rate region with positive gradient on pressure-flow-rate curve,the experimental investigation was carried out at rotor inlet and outside of rotor blade tip without casing in a semi-opened propeller fan using a hot-wire anemometer.A single I-type hot-wire probe was used,and the data obtained were processed by the use of phase-locked averaging,ensemble averaging and FFT analyzing.The flow fields at rotor inlet and outside of rotor blade tip were discussed mainly using the results from distributions of velocity fluctuations and power spectrum density.It was found from these results that there are the two types of different periodical fluctuations and both of those frequencies were not the same of rotor rotating frequency(RRF;15Hz).One was observed at relatively high flow-rate region at relatively downstream area in measurement and its frequency was approximately 7Hz(47% of RRF).The other was observed at relatively low flow-rate region at relatively upstream area in measurement and its frequency was approximately 10Hz(67% of RRF)".As the velocity fluctuations with the flow fields are rapidly increased by the former fluctuation,it is thought that its fluctuation is the trigger of blade stall.展开更多
基金Project(2007CB613601) supported by the National Basic Research Program of ChinaProject(10C1095) supported by the Foundation of Hunan Educational Committee,China
文摘The leaching kinetics of low-grade copper ore with high-alkality gangues was studied in ammonia-ammonium sulphate solution.The main parameters,such as ammonia and ammonium sulphate concentrations,particle size,solid-to-liquid ratio and reaction temperature,were chosen in the experiments.The results show that the increase of temperature,concentrations of ammonia and ammonium sulphate is propitious to the leaching rate of copper ore.The leaching rate increases with the decrease of particle size and solid-to-liquid ratio.The leaching rate is controlled by the diffusion through the ash layer and the activation energy is determined to be 25.54 kJ/mol.A semi-empirical equation was proposed to describe the leaching kinetics.
文摘In order to clarify the unsteady flow fields at low flow-rate region with positive gradient on pressure-flow-rate curve,the experimental investigation was carried out at rotor inlet and outside of rotor blade tip without casing in a semi-opened propeller fan using a hot-wire anemometer.A single I-type hot-wire probe was used,and the data obtained were processed by the use of phase-locked averaging,ensemble averaging and FFT analyzing.The flow fields at rotor inlet and outside of rotor blade tip were discussed mainly using the results from distributions of velocity fluctuations and power spectrum density.It was found from these results that there are the two types of different periodical fluctuations and both of those frequencies were not the same of rotor rotating frequency(RRF;15Hz).One was observed at relatively high flow-rate region at relatively downstream area in measurement and its frequency was approximately 7Hz(47% of RRF).The other was observed at relatively low flow-rate region at relatively upstream area in measurement and its frequency was approximately 10Hz(67% of RRF)".As the velocity fluctuations with the flow fields are rapidly increased by the former fluctuation,it is thought that its fluctuation is the trigger of blade stall.
