Preparation And Characterization Of Micro-nano Calcium Carbonate

Micro-nano calcium carbonate preparation methods are carbonization,metathesis method,microemulsion method and gel method.In this paper,the method of metathesis and carbonization were used to prepare micro-nano calcium carbonate.The metathesis method was divided into two systems: sodium carbonate system and ammonium carbonate.The kinetic study on the thermal analysis of micro-nano-calcium carbonate.The effects of stirring rate,reaction temperature,dropping rate and molar ratio of calcium chloride to sodium carbonate on the particle size of micro-nano calcium carbonate were studied.The effects of stirring rate,reaction temperature,dropping rate and calcium carbonate on the micro-nano calcium carbonate were studied.The stirring rate was 300 r / min,the reaction temperature was 20 ?,the rate of dropping was 14.43ml/min the molar ratio of calcium chloride and sodium carbonate was 1: 2,Add additives under optimized conditions.The effects of additives,inorganic additives and organic additives on the particle size and morphology of micro-nano-CaCO3 were investigated.(XRD),field emission scanning electron microscopy(FESEM)and TA-DTG were used to characterize the micro-nano calcium carbonate.The results showed that when the additive was EDTA,EDTA disodium and EDTA tetrasodium,With the increase of additive concentration,the particle size of micro-nano calcium carbonate increased,the control particle size value is small,should choose low concentration of such additives.The reaction conditions were as follows: the reaction temperature was 30 ?,The molar ratio of calcium chloride to ammonium carbonate is 1: 2,the mixture was stirred at 300 r / min,and the peristaltic pump dropping the flow rate of 3.591.The microcrystalline calcium carbonate was prepared by using calcium chloride and ammonium carbonate as raw materials,to find the control of micro-nano calcium carbonate into the ball of the additive.There are: EDTA,EDTA disodium,EDTA trisodium,EDTA tetrasodium,L-glutamic acid,PVP,?-cyclodextrin,sodium polyphosphate,pentaerythritol,sodium pyrophosphate,sodium dihydrogen phosphate,Sodium metaphosphate,sodium dichromobenzene sulfonate,sodium tetraborate and the like,and various additives such as sodium metaphosphate,potassium hexacyanocobaltate,sodium molybdate,citric acid,sodium citrate,sodium trimetaphosphate,sodium dodecylbenzenesulfonate and sodium tetraborate.Such additives can make micro-nano calcium carbonate into a ball.Calcium hydroxide and carbon dioxide were used as raw materials to prepare micro-nano calcium carbonate by carbonization method.The ratio of carbon dioxide to nitrogen,the rate of stirring,the reaction temperature,the ratio of calcium oxide and water were selected to carry out single factor experiment.The ratio of carbon dioxide to nitrogen is 2: 1,the stirring rate is 30 r / min,the reaction temperature is 60 ?,the ratio of calcium oxide to water is 1:15,which is the best experimental condition.The minimum particle size is 4.03 ?m.The effects of EDTA and its derivatives on the morphology of micro-nano calcium carbonate were studied.The thermal analysis kinetics of micro-nano calcium carbonate products prepared with calcium chloride and sodium carbonate as raw materials was studied.Get a second-order kinetics model: d(a)/ dT = A / ?e-E / RT./ 4(1-a)[-ln(1-a)] – 3,E = 1454450kJ/mol,A=183.9622 s-1.