Experimental investigation of the inhibition of deep-sea mining sediment plumes by polyaluminum chloride  

作　　者：Fengpeng Zhang Xuguang Chen Jiakang Wei Yangyang Zhang Weikun Xu Hao Li 

机构地区：[1]College of Engineering,Ocean University of China,Qingdao 266100,China [2]Shandong Province Key Laboratory of Ocean Engineering,Ocean University of China,Qingdao 266100,China [3]China Merchants Marine and Offshore Research Institute Co.,Ltd.,Shenzhen 518000,China [4]National Deep Sea Center,Qingdao 266237,China

出　　处：《International Journal of Mining Science and Technology》2024年第1期91-104,共14页矿业科学技术学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.52225107,U2106224,U1906234,51822904,and U1706223);the Fundamental Research Funds for the Central Universities(No.202041004)

摘　　要：Deep-sea sediment disturbance may occur when collecting polymetallic nodules,resulting in the creation of plumes that could have a negative impact on the ecological environment.This study aims to investigate the potential solution of using polyaluminum chloride(PAC)in the water jet.The effects of PAC are examined through a self-designed simulation system for deep-sea polymetallic nodule collection and sediment samples from a potential deep-sea mining area.The experimental results showed that the optimal PAC dose was found to be 0.75 g/L.Compared with the test conditions without the addition of PAC,the presence of PAC leads to a reduction in volume,lower characteristic turbidity,smaller diffusion velocity,and shorter settling time of the plume.This indicates that PAC inhibits the entire development process of the plume.The addition of PAC leads to the flocculation of mm-sized particles,resulting in the formation of cm-sized flocs.The flocculation of particles decreases the rate of erosion on the seabed by around 30%.This reduction in erosion helps to decrease the formation of plumes.Additionally,when the size of suspended particles increases,it reduces the scale at which they diffuse.Furthermore,the settling velocity of flocs(around 10^(-2) m/s)is much higher that of compared to sediment particles(around 10^(-5) m/s),which effectively reduces the amount of time the plume remains in suspension.

关 键 词：Deep-sea mining Deep-sea polymetallic nodules Sediment plume Polyaluminum chloride Jet impact Particle flocculation 

分 类 号：P744[天文地球—海洋科学]