Study On The Inhibitory Effect Of Polyethylene Oxide On The Dispersion Behavior Of Clay In Slime Water

Clay is the main ash-forming mineral in coal,and its content accounts for more than half of the total gangue minerals contained in coal.Among them,swelling clay,such as montmorillonite,has a dynamic process of "surface hydration-osmotic expansion-crystal layer dispersion" in water.After the clay particles expand,the crystal layer spacing and volume increase,and they are easily dispersed into micron or even nanometers.Particles make it difficult for slime water to settle.The thesis takes montmorillonite as the research object and polyethylene oxide(PEO)as the inhibitor to study the effect of PEO on the dispersion behavior of clay in slime water,compare the natural dispersion system of montmorillonite and montmorillonite under inhibited and non-inhibited conditions Dispersion law,with the help of particle size test,rheology test,electrodynamic test,sedimentation test,cryo-scanning electron microscopy test,atomic force microscopy test,X-ray diffraction analysis,infrared spectroscopy and other means for analysis and characterization,aiming to reveal low molecular weight PEO The main conclusions are as follows:(1)In a natural dispersion system,montmorillonite particles are dispersed due to hydration expansion.After 36 hours of dispersion,the average particle size gradually decreases from 415.07 nm to about 88.35 nm,and the proportion of particles smaller than 100 nm increases from 0% to 74.76.%;The viscosity of the system gradually increased from 2.71 m Pas to 3.83 m Pas;the proportion of particles with a zeta potential value of less than-40 m V increased from 34.86% to 92.28%,and the average zeta potential increased from-39.17 m V to-52.94 m V.(2)PEO is added as a suppression system at the beginning of montmorillonite hydration,and after the dispersion is complete,it is added as a non-inhibition system.In the 2000 PEO non-inhibited system,the particle size of less than 200 nm accounted for 95.12%,the particle size greater than 600 nm accounted for 4.88%,the particle size of the suppressed system was less than 200 nm accounted for 73.56%,and the particle size greater than 600 nm accounted for 15.46%,indicating that PEO under non-inhibited conditions is mainly Flocculation,inhibition of dispersion and flocculation coexist under inhibiting conditions.In the dispersion system with the addition of PEO inhibitor,PEO inhibition can significantly increase the particle size of the dispersion system,reduce the viscosity of the system and the proportion of particles with low zeta potential,and its inhibitory effect will increase with the increase of molecular weight and concentration.(3)The study on the mechanism of PEO inhibiting the dispersion of montmorillonite shows that the interlayer spacing of montmorillonite is increased from 12.37 ? to about 14.61 ? after being restrained by PEO,and the sample has a spiral structure of PEO at 1355 cm-1 and 844 cm-1.The characteristic peak of PEO exists between the montmorillonite layers in a spiral structure,so that tightly connected hydrogen bonds are formed between the upper and lower unit crystal layers of the montmorillonite to inhibit the dispersion of the crystal layer particles,and the particle crystal layers are tightly combined face-to-face Large particles are dispersed in water.(4)Research on the effect of PEO on the sedimentation performance of coal slurry shows that when the distance between unexpanded montmorillonite and coal particles is reduced to 20 nm,a monotonically increasing attraction begins to appear,and the force between the expanded montmorillonite and coal particles changes from attraction to repulsion The change of force and interaction between particles may be due to the difference in the thickness of the hydration film.60 WPEO inhibits the force between montmorillonite and coal particles in the range of 25 nm,which makes the slime particles maintain a larger particle size of about 392.83 nm and improves the sedimentation performance of the slime water.The higher the molecular weight of PEO and the lower the concentration of slime water under the condition of slime water inhibition,the better the sedimentation performance of the slime water.Under the condition of adding 60 W molecular weight PEO,the thickness of the sedimentation layer can be stabilized at about 10 mm after the 10g/L slime water system settles for 30 minutes.The paper has 42 pictures,21 tables and 89 references.