Thickening sedimentation and sand discharge of tailings slurry under ultrasonic
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摘要: 為了提高砂倉中尾砂濃密效率,實現高濃度的放砂,引入聲場作為研究手段,創新性的利用聲場輻射方式傳播的特性,將聲場非接觸性地作用于尾砂漿介質中.通過設計試驗,配制質量分數為40%的尾砂砂漿,在尾砂漿分別沉降15,20,25,30,35和40 min后,施加頻率20 kHz,功率50 W的超聲波,探究不同沉降時間后施加超聲波作用對最終沉降時間和濃度的影響,同時將超聲波作用在砂倉放砂階段,并對超聲波作用后不同濃度的砂漿進行流變參數測定.試驗結果表明:在沉降20 min后施加超聲波,砂漿沉降濃密時間最短為80 min,尾砂漿最終質量分數可達77.5%,與此同時超聲波作用下可以實現砂倉穩定高濃度的放砂,放出砂漿質量分數為74.04%.對比超聲波處理前后砂漿黏度與屈服應力可知,超聲波可有效降低砂漿黏度22.3%,具有良好的降黏效果.超聲波的振動作用,空化作用以及聲流效應是使得砂漿快速濃密沉降以及放出的原因.Abstract: To improve the thickening efficiency of tailings in sand bins and achieve a high-concentration sand discharge, the sound field as a research method was introduced, and the characteristics of sound-field radiation to transmit the non-contact sound field was innovatively used to tailings slurry. Tailings slurry with 40% in mass fraction was prepared for the experiment. After 15, 20, 25, 30, 35, and 40 min of sedimentation, an ultrasonic wave of 20 kHz and 50 W of power were applied to investigate the effect of ultrasonic waves on the final settling time and concentration with different settling times. Ultrasonic wave was also applied to the sand discharge stage, and the rheological parameters of the tailings slurry at different concentrations were measured. The results show that when an ultrasonic wave is applied after 20 min of sedimentation, the shortest slurry sedimentation time of 80 min can be obtained and the final sediment mass fraction of the tailings slurry can reach 77.5%. Therefore, under ultrasonic action, it is possible to achieve stable sand discharge with a high-concentration tailings slurry at the same time, and the discharge mass fraction up to 74.04%. Comparisons of the viscosity and yield stress of the tailings slurry before and after ultrasonic treatment indicate that the viscosity of the slurry can be effectively reduced by 22.3% by ultrasonic action, which is a good viscosity reduction effect. Ultrasonic vibration, cavitation, and the acoustic streaming effect are the reasons for the rapidly thickening sedimentation and discharge of the tailings slurry.
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Key words:
- ultrasonic wave /
- vertical silo /
- thickening sedimentation /
- slurry discharge /
- backfill mining
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參考文獻
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