Study On Preparation,Stability And Gelling Property Of Nano-CaCO₃/SiO₂ Composite Dispersion System

With the continuous progress of modern chemical industry and material science,the application of nanomaterials in the field of engineering is becoming more and more common.In the engineering applications of mine,foundation reinforcement and anti-seepage and water plugging,the stability and gelling of nanocomposites is one of the key problems that need to be solved.In this paper,a series of Nano-Ca CO₃/Si O₂ composite dispersion systems were prepared,and the effects of dispersants,experimental parameters and the amount of nano-materials on the dispersion,particle size distribution,surface charge and viscosity of the composite systems were studied.On this basis,Si O₂,was prepared from high silicon tailings and the dispersion stability of Nano-Ca CO₃/high silicon tailings Si O₂composite system was studied.In the best dispersion system of Ca CO₃ and Si O₂,the effects of gelling agents and test parameters on the gelling property of the composite system were studied.The dispersion and gelling samples of each composite system were characterized and analyzed by infrared(FTIR),thermogravimetric(TG)and electron microscope(SEM).The prepared Nano-Ca CO₃/Si O₂ composite dispersion system has good stability in aqueous solution.The proportion and addition of Nano-materials mainly affect the average particle size of the composite dispersion system,the type,concentration and p H value of the dispersant mainly affect the dispersion degree of the composite dispersion system,and the temperature mainly affects the viscosity of the composite dispersion system.When polyacrylamide and sodium hexametaphosphate are used as composite dispersants,the concentration of dispersant is 7%,the temperature is 55?,the p H value is 9,and the mass ratio of Nano-Ca CO₃ and Si O₂ is 65:35,the stability of the composite dispersion system is the best.Under this condition,the average particle size of the Nano-Ca CO₃/Si O₂ composite dispersion system is 5.26?m,and when the viscosity is 18 mpa.s,the dispersion degree of the Nano-Ca CO₃/Si O₂ composite dispersion system is 97.5%for 24 h.Under the alkaline condition,the composite dispersant increases the absolute value of the surface charge of the nano-particle diffusion double layer and increases the electrostatic repulsion between the particles,which makes the composite system show good dispersion stability.By adjusting the experimental parameters and composite gelling agent,the Nano-Ca CO₃/Si O₂composite system with controllable gelation time was obtained.There is an exponential relationship between gelling time and gelling agent concentration and temperature,and through the analysis of experimental data,the fitting equations between gelling time and gelling agent concentration,gelling time and temperature are established respectively.With the addition of compound gelling agent sodium carboxymethyl cellulose(CMC),ferric chloride and calcium hydroxide,the moisture content of Nano-Ca CO₃/Si O₂ composite system decreased but the concentration increased,and the collision probability between Nano-Si O₂ particles increased.Si O₂particles bonded and gathered with each other,and silicon hydroxyl dehydration and condensation occurred between Si O₂ particles,resulting in good gelling performance of Nano-Ca CO₃/Si O₂ composite system.Using high silicon tailings as silicon source,Si O₂ was prepared by optimizing the conditions.The suitable test scheme is that the amount of dissolved water is 50 m L/g to produce sodium silicate,the concentration of hydrochloric acid is 4.8 mol/L,and the amount of surfactant polyethylene glycol 2000is 0.6 g/g tailings.Compared with the commercial Nano-Si O₂ dispersion system,the stability of the Nano-Ca CO₃/high-silicon tailings Si O₂composite dispersion system is slightly lower under the optimal dispersion system conditions.Under this condition,the average particle size of the composite dispersion system is 8.12?m,and when the viscosity is 16 mpa.s,the dispersion degree is 73.5%for 24 h.The gelling time can be effectively controlled by optimizing the concentration and temperature of composite gelling agent CMC,ferric chloride and calcium hydroxide solution.There are 47 figures,34 tables,and 99 references in this paper.