Effect Of Crystal Oriented Agents On Modification Of Nanometer Calcium Carbonate

Calcium carbonate is a inorganic nonmetallic materials that is widely applied in the field of chemical industry,building materials,medicine,metallurgy,papermaking,plastics,rubber,paint.Nano calcium carbonate is a high performance calcium carbonate powder on nano scale.Nano calcium carbonate not only has all the attributes of the ordinary calcium carbonate andit also has the nano characteristics that ordinary calcium carbonate does not have.Therefore,the research and development of nano calcium carbonate products are highly valued by people.To obtain suitable nano calcium carbonate products for different applications,in the synthesis of nano-calcium carbonate,different crystal oriented agent are often added to the synthetic emulsion to change the crystal structure of the synthesized calcium carbonate.Crystal orientation agent can not only control the morphology and particle size of nanometer calcium carbonate,at the same time there is certain effect of nano calcium carbonate modified for different kinds of activator.Therefore,article that choose a variety of crystal orientation agent and activator made a systematic study.By discontinuous and carbonation method in research process,under certain conditions in the process parameters such as initial temperature,CO2ventilation,the concentration of Ca(OH)2,By adding different kinds of crystal oriented agents,such as hydroxyl group,carboxyl group and inorganic salt,nano calcium carbonate with different crystal structure was prepared.Then,the nano calcium carbonate was modified by different modifiers.In addition,study the stearic acid and titanate coupling agent modification for nanometer calcium carbonate and determine the best conditions of two kinds of modifier.The results show that the addition of crystalline orientation agent when synthesizing nano calcium carbonatehas has obvious effect on the modification of nano calcium carbonate.The effect of different crystal oriented agents on the activation of different type of modifiers is different.When adding to hydroxyl crystal orientation agent in the synthesis of nanometer calcium carbonate,the effect of modification of the surface of the nano calcium carbonate shows that The addition of starch can promote the modification of nano calcium carbonate by stearic acid,but it can inhibit the modification of JN-115 to nano calcium carbonate.The addition of sucrose was not beneficial to the modification of nano calcium carbonate by stearic acid and JN-115.When adding to hydroxyl crystal orientation agent in the synthesis of nanometer calcium carbonate,the effect of modification of the surface of the nano calcium carbonate shows that the activation index of nano calcium carbonate modified by JN-115was decreased when adding to EDTA,citric acid and acrylic acid;Citric acid,acrylic acid and EDTA(2%,3%)can inhibit the modification of stearic acid to nano calcium carbonate;The addition of sucrose was not beneficial to the modification of nano calcium carbonate by stearic acid and JN-115.When adding to hydroxyl crystal orientation agent in the synthesis of nanometer calcium carbonate,the effect of modification of the surface of the nano calcium carbonate shows that the activation index of nano calcium carbonate modified by JN-115was decreased when adding to ZnSO4(2%,3%),Al2(SO4)3(2%,3%),MgCl2(1%,3%);The addition of zinc ZnSO4(1%),Al2(SO4)3(1%)and MgCl2(2%)can promote the modification of stearic acid and JN-115 to nano calcium carbonate;Sodium silicate can promote the modification of nano calcium carbonate,but it can inhibit the modification of JN-115;Addition of sodium pyrophosphate can inhibit modification of nano calcium carbonate by JN-115;The addition of sodium phosphate(1%)was beneficial to the modification of stearic acid,The addition of sodium phosphate(2%,3%)was not conducive to the modification of stearic acid.Mechanism analysis showsthroughspecific surface area:When modifying agent is stearic acid and adding different dosage of the crystal orientation,the change of the activation index was mainly due tothe particle size of nanometer calcium carbonateaffectedcrystal orientation agent.When modifying agent is JN-115 and adding different dosage of the crystal orientation,on the one hand,the change of the activation index was mainly due tothe changes of nanometer calcium carbonate particle size,on the other hand,there is adsorption force between JN-115 and crystal orientationagent.