Synthesis Of Calcium Carbonate Particles With Different Morphology By High-gravity Reactive Precipitation And The Application On Template

Calcium carbonate,a kind of important inorganic chemical raw materials,has been widely used as filling agent and reinforcing agent in printing ink,papermaking,paint and other fields.Along with the social development,people are increasingly demanding regarding the quality of the calcium carbonate,especially in the area of specific morphology of light calcium carbonate.The morphology and particle size of calcium carbonate have an important impact on its function and application fields.Therefore,the study of preparation processes of calcium carbonate with different morphology,has become research emphasis of relevant scientific workers.This paper,the method of high-gravity precipitation with different additive and template agent has been adopted to synthesize whisker,globular and petals flake three different morphology of calcium carbonate.The hollow spherical calcium carbonate has been prepared in normal gravity field,and the polyvinylpyrrolidone?PVP?and sodium dodecyl sulfate?SDS?are used as the composite additive organic templates.The influences of reactive temperature,rotating speed of rotating packed bed?RPB?and the concentration of reactants have been studied to obtain the best preparation conditions.The study found that CaCO₃ whisker obtained from Ca?OH?₂ slurry by carbonation earried out in RPB with H3PO4 as additives.This experimental results showed that unbroken CaCO₃ whisker with average diameter of 144 nm,average aspect ratio about 19.4 and 97.5%aragonite phase could be prepared under the following operation condition:reactive temperature,70?;rotating speed of RPB,1400 r·min^-1;Ca?OH?₂ initial slurry concentration,80 g·h^-1;drying time,70 h.Secondly,globular CaCO₃ obtained from CaC12 solution and CO₂ by carbonation carried out in RPB with soluble starch as additives and ammonia as pH control agent.The experimental results showed that CaCO₃ with a single globular structure and average diameter of 14.01 ym could be prepared;The petals flake CaCO₃ obtained from CaC12 solution and CO₂ by carbonation carried out in RPB with ammonia as pH control agent.The experimental results showed that CaCO₃ with a single petals flake structure and average diameter of 510 nm could be prepared;The hollow spherical CaCO₃ particles obtained from CaC12 solution and Na2CO3 by double decomposition method with organic polymer as soft templates.The experimental results showed that CaCO₃ with a single hollow spherical structure and average diameter of 4 ?m could be prepared.The study has a certain guiding significance on industrialized production of CaCO₃ with different morphology.Calcium carbonate is characteristic of low cost,varieties of morphology,non-toxic and easy to eliminate.CaCO₃ is extensively used as template agent in the preparation of specific morphology of carbon materials.The dopamine film?PDA?is synthesized on surface of hollow spherical calcium carbonate and whisker calcium carbonate as a template.After dealing with the high temperatUre carbonization and washing,get with the hollow spherical and whisker carbon material.The series of regular shape porous carbon materials were prepared at different carbonization temperature.In the process of high temperature carbonization,calcium carbonate not only have effect of supporting morphology,but also the role of high efficiency reaming.The result shows that the hollow whisker whose surface area was up to 1193.0 m2·g^-1,Brunaner-Emmett-Teller was 819.9 m2·g^-1 and yield of 46.0%at 700? of carbonization temperature.The result shows that the hollow sphere whose surface area was up to 1082.2m2·g^-1,Bruner-Emmett-Teller was 742.2 m2·g^-1 and yield of 50.48%at 750? of carbonization temperature.The Brunauer-Emmett-Teller of carbon materials has been dramatically improved over the pure dopamine after carbonization,20.6 m2·g^-1 and provides a new idea about facile preparing porous carbon materials.