摘要:
在超声波与机械场中对比研究了搅拌强度、超声波电流强度、浸出时间对钒浸取过程耗酸量、钒浸出率的影响。结果表明:随着搅拌强度的增加,超声波场中耗酸曲线稳定性较好,钒浸出率较高;随着超声波电流强度的增加,耗酸稳定性增加,钒浸出率增加;随着浸出时间的增加,超声波场与机械场中钒浸出率在30 min内急剧增加,在30min后增加缓慢,超声波场中钒浸出率达到97%以上,而机械场中钒浸出率仅有94%。采用外扩散、化学反应、内扩散速率控制方程比较分析了两个反应阶段的速率控制步骤,分析结果表明第一时间段反应速率受外扩散反应步骤控制,超声波与机械场中的外扩散反应速率常数分别为0.020 7、0.018 9 min-1,速率控制方程分别为:1-3(1-η)2/3+2(1-η)=0.020 7 t,1-3(1-η)2/3+2(1-η)=0.018 9 t;第二时间段反应速率受化学反应步骤控制,超声波与机械场中的化学反应速率常数分别为0.005 3 min-1,0.003 8 min-1,速率控制方程分别为:1-[(1-η)/(1-0.937 1)]1/3=0.005 3(t-30),1-[(1-η)/(1-0.919 1)]1/3=0.003 8(t-30)。
关键词:
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提钒 /
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浸出 /
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超声波场 /
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机械场 /
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动力学强化
Abstract:
The effects of mechanical stirring intensity,ultrasonic current intensity and leaching time on acid consumption and leaching ratio for vanadium leaching process respectively in ultrasonic and mechanical field were investigated.The results show that with increase of stirring intensity,the acid consumption curve in ultrasonic field reveals well stability with a higher vanadium leaching rate.The stability of acid consumption and leaching ratio of vanadium are enhanced with increase of ultrasonic current intensity.In both of ultrasonic and mechanical field,leaching ratio of vanadium sharply increases in first 30 min then gently raises with increase of leaching time,resulting in vanadium leaching rate of more than 97% in ultrasonic field but 94% in mechanical field.The rate controlling steps of two reaction stages were comparatively analyzed using rate control equations of external diffusion,chemical reaction and internal diffusion,respectively.It is indicated that the rate in the first stage is controlled by external diffusion,with 0.020 7 min-1 of rate constant and 1-3（1-η）2/3+2（1-η） =0.020 7 t of rate equation for leaching in ultrasonic field while 0.018 9 min-1 of rate constant and 1-3（1-η）2/3+2（1-η） = 0.018 9 t of rate equation for leaching in mechanical field.The rate in the second stage is of chemical reaction control.The rate constant and rate equation for leaching are separately determined as 0.005 3 min-1 and 1-[（1-η）/（1-0.937 1） ]1/3= 0.005 3（t-30） in ultrasonic field,but respectively 0.003 8 min-1 and 1-[（1-η）/（1-0.919 1） ]1/3= 0.003 8（t-30） in mechanical field.
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