Study On Effect Of Illite On The Filtration Mechanism Of Coal Slime Water

Coal is an important basic energy source in China,but the extensive use of coal has adversely affected the environment.Coal preparation is the source of clean coal utilization.Wet coal preparation will produce a lot of slime water,and the clay minerals in the slime water are easy to slime,making the slime dehydration difficult.Illite is a 2:1 clay mineral,fine-grained illite is easy to mud,and the multiple faces formed are complex with the slime aqueous solution and seriously affect the slime dehydration.This article mainly studies the effect of fine-grained illite on the slime water filtration mechanism,investigate the influence of factors such as pharmacy system and solution environment on the dehydration effect of illite-containing slime water,filter test used cationic filter aid 1831,anionic filter aid SDBS and non-ionic filter aid NPAM;And use Materials Studio 8.0 software by molecular dynamics(MD)simulation to study the aggregation state of a large number of water molecules on the surface of fine illite from a microscopic perspective and density functional(DFT)simulation to study the adsorption behavior of water molecules on the surface of illite.Concluded as follows:(1)Fine-grained illite is dominated by lamellar structure,and the surface contains active functional groups.There is a strong charge repulsion between the illite particles in the slime water,which makes the illite dispersed in the slime water.(2)Through the experimental research on the filtration of slime water containing illite,it is found that with the increase of the illite mass fraction,the filtration time of the slime water is extended and the moisture of the filter cake increases;When the illite mass fraction exceeds 8%,the filtration and dehydration effect of the slime water is sharp deterioration;When the dosage of the agent is less than 50 g/t,the effect of 1831 is the best for improving the dehydration speed of illite-containing slime water and reducing the moisture of filter cake,followed by NPAM,and the effect of SDBS is poor.(3)Through the molecular dynamics simulation study on the effect of filter aid on the hydration of illite surface,it is concluded that the water molecule aggregation effect on the illite(001)surface:SDBS>NPAM>1831,the water on the illite(001)surface under the action of SDBS It is easier to gather to form a hydration membrane;The deformation of the cationic filter aid 1831 on the illite(001)surface is small,the non-polar carbon chain is outward,the anionic filter aid SDBS leaves the initial position of the illite(001)surface,and the structure is distorted,the nonionic type The filter aid NPAM has a stable adsorption structure and small deformation,it shows that anionic filter aid is not suitable as a hydrophobic modification agent for illite(001)surface.(4)Through the density functional simulation study of the adsorption behavior of water molecules on the surface of illite,it is found that the adsorption energy of the(001)plane is-0.34?-0.46 eV,and the adsorption energy of the(010)plane is-0.50?-0.77 eV,indicating that illite(010)surface The adsorption of water molecules is stronger than the(001)surface.Among them,?(010)is the most stable configuration.In this configuration,a part of the water molecules are embedded between the illite layers.A certain degree of coordination occurs between the O_W of the water molecules and the K~+between the illite layers.The atoms form a hydrogen bond(H_W...O_I)with the oxygen atoms on the(010)plane of illite,and the adsorption energy of?(010)is-0.77eV.