The Additive Inhibits The Molecular Simulation Of The Secondary Reaction Of Alumina Clinker Dissolution

The proportion of calcium silicate in clinker is up to 30%,and it can’t be dissolved in water.However,in the process of dissolution,2CaO·SiO2 in the red mud can occur a series of chemical reactions with sodium aluminate solution,which makes part of Al2O3 and Na2 O that have been dissolved retransfer to red mud and loses,those reactions are called secondary reaction.For the secondary reaction to this problem,this paper carried out the use of additives polyacrylic acid(PAA)and acrylic acid-hydroxypropyl acrylate copolymer(T-225)study clinker dissolution suppressing secondary reactions,Additive adsorbs and wraps on the surface of calcium silicate,and inhibits the decomposition of crystal,thus the dissolution rate of alumina has been improved.Currently,the use of an additive to inhibit the secondary reaction,due to the simplicity of its operation by the majority of professionals and researchers concerned.Although experimental studies on the additive to inhibit secondary reactions more,but additive inhibition mechanism is still not very clear,the basic use of the additive selection method attempts,the lack of effective theoretical guidance.This paper uses Materials Studio 8.0 software as the computing platform.In the vacuum,pure water solution,and sodium aluminate solution environment,using molecular dynamics simulation method simulates and studies interaction behaviors of PAA additive,T-225 additive,and β-dicalcium silicate crystal.Mechanism of additive’s adsorbing crystals is analyzed by some aspects such as adsorption energy,the non-bond energy,radial distribution function and dihedral angle of addictive and crystals.The results of the new efficient design and preparation of the additive to provide theoretical guidance,have a positive theoretical and practical significance.The simulation results show that: in a vacuum environment,the binding energy of PAA is different from that of different crystal planes,wherein the maximum interaction energy is β-dicalcium(110)crystal plane,and the intensity sequence of different crystal planes as follows:(110)>(011)>(101)>(010)>(001)>(100);in the vacuum,pure water solution,and sodium aluminate solution environment,binding energy between PAA additive and β-dicalcium silicate crystal plane,between T-225 additive and β-dicalcium silicate crystal plane are both negative,moreover,binding energy in a vacuum environment is at maximum,pure water solution is next,and sodium aluminate solution is the smallest;when the molecular weight of the additive is within a certain range,binding energy of PAA and T-225 of different chain lengths with β-dicalcium silicate crystals can be increased with increasing chain length of additive;through a variety of system interaction,radial distribution functions and adsorbing conformation figure analysis,that PAA addictive,T-225 addictive is mainly through Coulomb electrostatic adsorbing on the(110)plane of β-dicalcium has been found;water molecules in aqueous environments are approximately multilayer adsorbing on β-dicalcium silicate crystals,H and O within PAA and T-225 have formed hydrogen bonds with water molecules,and Ca atoms in crystals have formed ionic bonds with carbonyl and alcohol O in additive;in the vacuum,pure water solution,and sodium aluminate solution environment,when the simulation conditions are the same,the ability to adsorb β-dicalcium crystals of T-225 with multiple functional groups is much stronger than PAA with only a single functional group;the molecular dynamics simulation results also vary widely as to carboxyl in different positions of PAA and T-225,and chain end carboxyl’s fluctuations twist is much stronger than mid-chain carboxyl’s,which shows mid-chain carboxyl’s adsorbing β-2CaO·SiO2 crystals is stronger than chain end carboxyl’s,and mid-chain carboxyl can adsorb on the surface of the crystals more effectively to the role of suppressing the clinker secondary reaction.