Research For Morphology Controlling Of Calcium Carbonate

Calcium carbonate is an important inorganic materials which is widely used inrubber,plastic,medicine,paint,ink,cosmetics,paper and other industries with differentmorphology.With the development of technical progress and the increasing of integratedrequirements in many fields,calcium carbonate is demand to be specialized, finer andfunctional.To control the morphology of calcium carbonate artificially tend to be moremeaningful by variety technical methods in order to improve it’s performance.Thereforethe research on preparing calcium carbonate and application of calcium carbonate withdifferent morphology is a way to increase the value of calcium carbonate.Notably,calciumcarbonate with micrometer spindle shape not only has the character of ultrafine calciumcarbonate but has excellent performance when added as a filler,which takes an importantrole in improving paper quality,such as reinforcing properties.Calcium carbonate withnanometer spherical shape can effctively improve the rheology and smoothness whenadded in high-grade printing ink. Now the present situation of preparing functionalcalcium carbonate have following problems:micrometer calcium carbonate of spindlemorphology with a high viscosity,nanometer calcium carbonate of spherical morphologywith uneven distribution and the morphology was not easy to be controlled. In thispaper,functional micrometer calcium carbonate of spindle morphology and nanometercalcium carbonate of spherical morphology were prepared in the bubbling reactor bycarbonation method.A series of experiments were carried out to prepare spindle micro-calcium carbonateand spherical nano-calcium carbonate by carbonization method in this paper. The effectsof reaction conditions such as the process of calcination of limestone,hydration process oflime and carbonation reaction(the type of crystal control agent, added amount,initialtemperature,velocity,concentration of raw materials on the crystal shape and size ofcalcium carbonate were also studied.The results show that when the reaction temperatureis controlled in20℃,the concentration Ca(OH)2is86-130g/L,gas velocity is0.114m/s,Ais added as a crystal control agent added to1%,then spherical calcium carbonate with thesize of20-50nm well-dispersed and narrow distribution calcium carbonate wasprepared.When the reaction temperature is50℃,the concentration of Ca(OH)2is130g/L,velocity is0.038m/s,D is added as a crystal control agent added to1%,then spindlecalcium carbonate with the size of1.2μm was prepared. The morphology of product was characted by scanning electron microscopy(SEM).The ideal results for the preparation ofspecial morphology calcium carbonate were obtained in amplification test which ismeaningful to increase the added value and enhance the competitiveness.