Abstract
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 investi-gate the potential solution of using polyaluminum chloride(PAC)in the waterjet.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 opti-mal 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 veloc-ity,and shorter settling time of the plume.This indicates that PAC inhibits the entire development pro-cess 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 set-tling 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.
基金项目
National Natural Science Foundation of China(52225107)
National Natural Science Foundation of China(U2106224)
National Natural Science Foundation of China(U1906234)
National Natural Science Foundation of China(51822904)
National Natural Science Foundation of China(U1706223)
Fundamental Research Funds for the Central Universities(202041004)
66th voyage of China Ocean's"Deep Sea No.1"scientific research vessel()
维普
万方数据