Enhanced dewatering effect of compound agents in pressurized filtration of flotation clean coal
In order to reduce the moisture of flotation concentrate filter cake and accelerate the cake formation speed,non-ionic polyacrylamide(PAM)with molecular weight of 7 million and non-ionic surfactant(L-64)were selected and dewatering tests were carried out in a laboratory pressurized filtration system using dosing methods such as separate addition and mixed addition.The mechanism of enhanced dewatering by compound dosing was investigated by contact angle measurement,infrared spectroscopy,surface tension of the filtrate and floc morphology observation.The results show that,PAM can accelerate the dewatering speed but the effect of water reduction is ordinary,L-64 can obviously reduce the moisture of clean coal but the filtration speed is ordinary;the compound addition of agents can significantly reduce the cake formation time and reduce the moisture of filter cake,under the same amount,adding PAM first and then L-64 is more beneficial to reduce the moisture of filter cake,and adding L-64 first and then PAM is more beneficial to reduce the cake formation time.We also proposed a dual objective dewatering efficiency enhancement level evaluation model based on filter cake moisture and cake formation rate,and gave the optimal dosage of compound agents.The compound dosing can improve the hydrophobicity of coal surface,reduce the surface tension of filtrate,and form a floc structure with good looseness and permeability,which is conducive to the removal of capillary water between coal particles,thus to achieve dual effect of reducing the moisture of filter cake and improving the filtration speed.
flotation clean coal dewateringfilter cake moisturecompound agentsdosing methodevaluation model
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