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Journal of Central South University 2019年第3期26卷 567-576页

作者： YUAN Zheng-cheng JIANG Zheng-wu CHEN Qing Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education School of Materials Science and Engineering Tongji University

The permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives was studied in this work. The parameters of calcium carbonate precipitation during self-healing were simulated. A permeability modeling of self-healing, combined with numerical simulation of calcium carbonate formation, was proposed based on the modified Poiseuille flow model. Moreover, the percentage of calcium carbonate in healing products was measured by TG-DTA. The simulated results show that self-healing can be dramatically promoted with the increase of pH and Ca2+ concentration. The calculated result of permeability is consistent with that measured for cracks appearing in middle or later stages of self-healing, it indicates that this model can be used to predict the self-healing rate to some extent. In addition, TG-DTA results show that the percentage of calcium carbonate in healing products is higher for mortar with only chemical expansion additives or cracks appearing in the later stage, which can more accurately predict the self-healing rate for the model.

关键词： cement-based material self-healing mineral additive calcium carbonate model

Evolution Mechanism of calcium carbonate in Solution

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Chinese Journal of Chemical Physics 2010年第6期23卷 731-737,746页

作者：郭亚平唐海雄周玉贾德昌宁聪琴郭亚军上海师范大学化学系上海200234 哈尔滨工业大学特种陶瓷研究所哈尔滨150001 中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室上海200050

calcium carbonate was synthesized in a CaCl2/NaCO3 mixed solution by using ethylenediaminetetraacetic acid （EDTA） as an additive. The thermodynamics and kinetics analyses indicate that although the driving force of amorphous calcium carbonate （ACC） precipitation is always less than that of calcite and vaterite precipitation, the nucleation rate of ACC is greater than that of calcite and vaterite at the initial stage of the precipitation reaction. With the increasing incubation time, vaterite and calcite particles nucleate heterogeneously by using the as-formed particles as active sites. Scanning electron microscopy images indicate that the transformation mechanism of ACC and vaterite to calcite is the dissolution-recrystallisation reaction. The presence of EDTA not only improves the stabilities of ACC and vaterite, but also leads to forming enlongated, connected rhombohedral calcite crystals after incubation 7 days in solutions. The ACC and vaterite are stabler in air than in solutions at room temperature, although the dissolution-recrystallisation reaction occurs on the surface.

关键词： calcium carbonate Dissolution-recrysatllisation reaction Phase transition

Crystalline-magnetism action in biomimetic mineralization of calcium carbonate

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中国化学工程学报:英文版 2023年第7期59卷 146-152页

作者： Chaoqun Wu Xun Liu Fujun Yao Xin Yang Yan Wang Wenyuan Hu State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyang 621000China Materials Science and Engineering Southwest University of Science and TechnologyMianyang 621000China National Health Commission Key Laboratory of Nuclear Technology Medical Transformation Mianyang Central HospitalMianyang 621010China

The influence of minor environmental factors,such as the geomagnetic field,on the biomineralization of nacres,is often ignored but a great deal of research has confirmed its important role in the normal mineralization of calcium *** the geomagnetic field is weak,its cumulative effects need to be considered given that the biomineralization process can take ***,the authors of this paper have investigated the effects of weak magnetic fields(25 Gs or 50 Gs)on calcium carbonate mineralization and analyzed the mechanism *** results show that even a weak magnetic field conduces to the formation of vaterite or aragonite,in the induction order of precursor→vaterite→*** stronger the magnetic field and the longer the time,the more obvious the induction *** effect of a magnetic field is strongest in the aging stage and weakest in the solution *** by egg-white protein and by a magnetic field inhibit each other,but they both restrict particle *** findings highlight the importance of minor environmental factors for biomineralization and can serve as a reference for biomimetic preparation of a CaCO_(3)nacre-like structure and for anti-scale technology for circulating cooling water.

关键词： Biomimetic mineralization calcium carbonate Magnetic field Egg-white protein

Granular porous calcium carbonate particles for scalable and high-performance solar-driven thermochemical heat storage

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Science China(Technological Sciences) 2021年第10期64卷 2142-2152页

作者： SONG Chao LIU XiangLei XUAN YiMin ZHENG HangBin GAO Ke TENG Liang DA Yun LI Chuan LI YongLiang DING YuLong School of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Thermal Management and Energy Utilization of Aviation Vehicles Ministry of Industry and Information TechnologyNanjing 210016China College of Environmental and Energy Engineering Beijing University of TechnologyBeijing 100124China Birmingham Centre for Energy Storage School of Chemical EngineeringUniversity of BirminghamBirmingham B152TTUK

calcium carbonate is promising thermochemical heat storage material for next-generation solar power systems due to its high energy storage density,low cost,and high operation *** have tried to improve energy storage performances of calcium carbonate recently,but most researches focus on powders,which are not suitable for scalable ***,novel granular porous calcium carbonate particles with very high solar absorptance,energy storage density,abrasive resistances,and energy storage rate are proposed for direct solar thermochemical heat *** average solar absorptance is improved by 234%compared with ordinary *** cycle stability and abrasive resistances are excellent with almost no decay of energy storage density over 25 cycles nor apparent particle weight loss over 24 h of continuous operation insides a planetary ball *** addition,the decomposition temperature is reduced by 2.8%–5.6%while the reaction rate of heat storage is enhanced by 80%–205%depending on the CO_(2) partial *** decomposition process of doped granular porous CaCO_(3) particles is found to involve three overlapping *** work provides new routes to achieve scalable direct solar thermochemical heat storage for next-generation high-temperature solar power systems.

关键词： thermochemical energy storage calcium carbonate solar absorptance cycle stability abrasive resistances kinetics analysis

CRYSTALLIZATION,MECHANICAL AND THERMAL PROPERTIES OF SORBITOL DERIVATIVES NUCLEATED POLYPROPYLENE/calcium carbonate COMPOSITES

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Chinese Journal of Polymer Science 2010年第4期28卷 457-466页

作者：王勇 Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong University

The effect of a phase nucleating agent （NA） 1,3：2,4-bis（3,4-dimethylbenzylidene） sorbitol （DMDBS） on crystallization and physical properties of polypropylene/calcium carbonate （PP/CaCO3） composites has been comparatively investigated. Compared with binary PP/CaCO3 composites, in which CaCO3 exhibits weak heterogeneous nucleation, inconspicuous reinforcement and toughening effects for PP, the introduction of a few amounts of DMDBS induces a great increase of the degree of crystallinity. Largely improved tensile properties, fracture toughness at relatively higher temperature and heat deformation temperature （HDT） are observed for DMDBS nucleated PP/CaCO3 composites.

关键词： Crystallization Physical properties Polypropylene calcium carbonate Sorbitol derivatives

Preparation of calcium carbonate particles coated with titanium dioxide

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International Journal of Minerals,Metallurgy and Materials 2009年第5期16卷 592-597页

作者： Hai Lin Ying-bo Dong Le-yong Jiang School of Civil and Environmental Engineering University of Science and Technology Beijing Beijing 100083 China

The preparation of a new mineral composite material, calcium carbonate particles coated with titanium dioxide, was studied. The mechanism of the preparation process was proposed. The new mineral composite material was made by the mechanoehemieal method under the optimum condition that the mass ratio of calcium carbonate particles to titanium dioxide was 6.5：3.5. The mass ratios of two different types of titanium dioxide （anatase to rutile） and grinding media to grinded materials were 8：2 and 4：1 respectively, and the modified density was 60%. Under this condition, the new material was capable of forming after 120-min modification. The hiding power and oil absorption of this new material were 29.12 g/m^2 and 23.30%, respectively. The results show that the modification is based on surface hydroxylation. After coating with titanium dioxide, the hiding power of calcium carbonate can be improved greatly. The new mineral composite materials can be used as the substitute for titanium dioxide.

关键词： calcium carbonate mechano-chemical process titanium dioxide film hydroxylation

The role of diffusion in the nucleation of calcium carbonate

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Chinese Journal of Chemical Engineering 2022年第3期35卷 275-281页

作者： Xiangyu Dou Haoyang Huang Yongsheng Han State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China

Nucleation widely exists in nature,from cloud formation to haze *** classical nucleation theory(CNT)was created to describe the nucleation process,but it fails to predict many experimental phenomena due to the short consideration of nanoscale phenomena and macroscale *** the attachment and detachment of monomers are considered in the developed model of nucleation,the diffusion of chemicals in the bulk is not valued as supersaturation in the nucleation process so *** we employ simulation and experimental approaches to investigate how the diffusion of ions affects the nucleation of calcium *** diffusion of ions is regulated by the viscosity of solvents and the sonication imposed on the *** is found that the nucleation rates increased exponentially with the diffusion coefficient of ions,which is beyond the prediction of *** abnormal finding might be ascribed to the involvement of cluster aggregation in the nucleation of calcium *** study highlights the significance of chemical diffusion in the nucleation process,which may help to revise the nucleation theory and develop solutions for the rational synthesis of materials,as well as for the control of air pollution.

关键词： calcium carbonate Nucleation Simulation Diffusion Dynamics

Mechanism of calcium carbonate Scale Deposition under Subcooled Flow Boiling Conditions

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Chinese Journal of Chemical Engineering 2005年第4期13卷 464-470页

作者： XING Xiaokai（邢晓凯） MA Chongfang（马重芳） CHEN Yongchang（陈永昌） College of Environmental and Energy Engineering Beijing University of Technology Beijing 100022 China

Fouling of heat transfer surfaces during subcooled flow boiling is a frequent engineering problem in process industries. It has been generally observed that the deposits in such industrial systems consist mainly of calcium carbonate （CaCO3）, which has inverse solubility characteristics. This investigation focused on the mechanism to control deposition and the morphology of crystalline deposits. A series of experiments were carried out at different surface and bulk temperatures, fluid velocities and salt ion concentrations. It is shown that the deposition rate is controlled by different mechanism in the range of experimental parameters, depending on salt ion concentration. At higher ion concentration, the fouling rate increases linearly with surface temperature and the effect of flow velocity on deposition rate is quite strong, suggesting that mass diffusion controls the fouling process. On the contrary, at lower ion concentration, the fouling rate increases exponentially with surface temperature and is independent of the velocity, illustrating that surface reaction controls the fouling process. By analysis of the morphology of scale, two types of crystal （calcite and aragonite） are formed. The lower the temperature and ion concentration, the longer the induction period and the higher the percentage of calcite nreciDitated.

关键词： heat transfer fouling calcium carbonate subcooled flow boiling

Preparation and Characterization of Three-dimensional Chrysanthemun Flower-like calcium carbonate

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Journal of Wuhan University of Technology(Materials Science) 2012年第4期27卷 708-714页

作者：陈先勇 Institute of Chemical Engineering Sichuan University College of Chemical and Environmental Engnineering Hubei University for Nationalities

calcium carbonate with three-dimensional chrysanthemun flower-like structure was successfully prepared from calcium chloride and sodium carbonate ethanol/water mixed solution by a simple precipitation method,using trisodium citrate as crystal *** experimental results show that the three-dimensional structure of chrysanthemun flower-like calcium carbonate is built up with several symmetrical micrometer multi-layer petals arranged around the multi-layer pancake-liked center,and the micrometer center and petals are assemblied by a large number of nanometer spherical particles with size 10-20 *** is found that the amount of trisodium citrate,the ethanol volume content has an important influence on the formation of this morphology.A possible mechanism is proposed to explain the formation of three-dimensional chrysanthemun flower-like calcium carbonate according the *** electron microscopy（SEM）,X-ray powder diffraction（XRD）,flourier transform infrared spectroscopy（FT-IR）,thermogravimety analysis（TG）,transmission electron microscopy（TEM） equipped with energy-dispersive X-ray（EDX）,and selected area electron diffraction（SAED） were used to characterize the crystals.

关键词： flower-like calcium carbonate precipitation method growth mechanism

Hierarchical porous calcium carbonate microspheres as drug delivery vector

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Progress in Natural Science:Materials International 2017年第6期27卷 674-677页

作者： Hui Yang Yunfeng Wang Tongxiang Liang Yiqun Deng Xiaopeng Qi Honghui Jiang Yangjun Wu Huichang Gao School of Materials Science and Engineering Jiangxi University of Science and Technology School of Medicine South China University of Technology A National Engineering Research Centre for Tissue Restoration and Reconstruction

CaCO;crystals with different hierarchical structure were fabricated by the precipitation of CaCO;in an aqueous solution containing guar gum（GG）. Through adjusting a range of parameters, the size distribution and microstructure of CaCO;were well controlled. Results showed that GG facilitated the formation of the hierarchical hollow sphere through assembling of nanocrystals, while inhibited the growth of CaCO;crystals and restrained phase transition from calcite to vaterite at high concentration of GG(C;) condition; Moreover, increasing reaction temperature led to larger particles and stable crystalline phase formed. According to the results, a morphology map was presented. Furthermore, Drug loading and releasing results ensured porous CaCO;microspheres a promising vector for drug delivery.

关键词： calcium carbonate Microspheres Phase transformation Morphology-controlled growth Biomedical application