Superfine Calcium Carbonate With Different Morphologies Synthesized By Carbonization Method, Double Decomposition Method And Reverse Microemulsion Method

The superfine calcium carbonate is a new type of superfine solid material with a huge potential andwide applications, high development value, is an important inorganic chemical products.This paperintroduces the development of modern calcium carbonate and calcium carbonate, and the fields of itsapplication and the preparation technology was elaborated and studied in detail.Methods of carbonation, microemulsion and metathesis three ways were used to synthesize differentmorphologies and sizes of ultra-fine calcium carbonate products. When the carbonization method isadopted, the same concentration of acetic acid and salicylic acid as a crystal controlling agent are added tostudy the impact of preparation of ultrafine calcium carbonate crystals under the same experimentalconditions. In the carbonation reaction process using the pH and conductivity meter to determine the end ofthe reaction and explore the reaction mechanism. Experimental results show that when crystal shape controlagent does not add, the product particle morphology is not uniform; particle size distribution is uneven;reunites is more serious; appearance is square or irregular. After using the crystal control agent, the productparticle size is uniform distribution, dispersion change slightly, the appearance is a bar and chain rules.The appropriate experimental conditions and operational processes are selected to add appropriateamount of adipic acid, xylitol, phenol, sodium carboxymethyl cellulose （CMC） and pentaerythritol ascrystal shape control agent in the metathesis method. The influence on preparation of ultra-fine calciumcarbonate crystallization is studied. The experimental results show that adding the same concentration ofadipic acid, xylitol and phenol as the crystal shape control agent can synthesize similar morphology ofcalcium carbonate particles, but different particle size. Different concentrations of CMC as a polymorphcontrol agents more obvious effect on the morphology and crystalline form of calcium carbonate, themorphology square transition to spherical, crystal calcite majority into vaterite majority. When usingdifferent concentrations of the pentaerythritol as crystal control agent, not only changed the morphology ofultrafine calcium carbonate but also changed its size and therefore the type of use of the additive and itseffects as the experimental data and the theoretical basis for this class of reaction provides a feasibleexperimental evidence and ideas.We first observed that when the mass ratio of CTAB to n-butanol is1:2,（CTAB+n-butanol） to n-hexane is1:3, and mole concentration of CaCl₂is2.0mol·L^-1, the CTAB/n-butanol/n-hexane/water（brine） oil-in-water （W/O） reverse microemulsion system can be configured into a stable micro-emulsion.The sodium carbonate solution was added dropwise to the calcium chloride microemulsion and the poolsize is controlled by adjusting the water and surfactant molar ratio ω0, thereby uniform particle sizedistribution of nano calcium carbonate prepared, and the size change from15to70nm range withinspherical nano-particles of calcium carbonate and explore ω0value and particle size relationship fromtheory to explain the formation mechanism of the reverse microemulsion and forming principle of thedifferent particle sizes of nano calcium carbonate.This paper studies prepared superfine calcium carbonate products using transmission electronmicroscopy （TEM）, scanning electron microscopy （SEM）, X-ray diffraction analyzer （XRD） on themorphology and crystal structure features characterize the experimental results and data for industrialPreparation of synthetic high value-added calcium carbonate provides a theoretical basis and experimentalbasis.