【作者】 贲智萍；

【导师】 余志伟；

【作者基本信息】 东华理工大学 ， 材料学， 2012， 硕士

【摘要】 高岭土作为天然硅铝酸盐矿物，在我国储量十分丰富。本论文采用高岭土进行煅烧制备偏高岭土，然后将偏高岭土采用水热合成过程中添加铝源的方式合成4A型分子筛。其工艺流程简单，具有扩大规模生产的可能性。本研究在绿色环保、高岭土深加工、降低分子筛制备成本、拓宽分子筛应用范围等方面考虑都具有重大的工业实用价值。在煅烧实验过程中，利用单因素实验法确定最佳煅烧温度为800℃，最佳煅烧时间为2h。通过差示扫描量热分析(DSC)、X射线衍射(XRD)、红外光谱(FT-IR)和扫描电镜(SEM)等分析测试手段对煅烧后的高岭土进行了物相、结构、形貌的分析，结果表明高岭土经过煅烧后得到了白度较高、杂质含量较少、颗粒较小、具有较高反应活性的偏高岭土。水热合成过程中，用单因素实验法确定了最佳工艺条件：n(SiO2)/n(Al2O3)=1.9；n(Na2O)/n(Al2O3)=2.4；n(H2O)/n(Na2O)=50；碱化温度为50℃；碱化时间为3h；结晶温度为90℃；结晶时间为6h。对在优化实验条件下合成的样品进行性能测试和结构表征，结果表明本论文合成出的4A分子筛各项性能指标符合国家标准：PH值为10.6、灼烧失重为22%、静态饱和吸水量为21%、钙离子吸附含量高达335mg/g(CaCO3)。样品经过DSC、XRD、FT-IR、SEM等分析后得出：样品含有沸石水结构，热稳定性较好，耐热温度达800℃，是纯度和结晶度都较高的4A分子筛，其晶体形状为立方形，且晶体生长完好，晶粒较小，粒度分布较均匀。最后讨论不同条件对4A分子筛对钙离子吸附的影响，研究表明，在Ca2+初始浓度为0.15mol/L的100ml溶液中，4A分子筛用量1g，pH值为10，温度为40℃，时间为60min的条件下，4A分子筛对Ca2+吸附容量达到172mg/g。在pH值固定的条件下，4A分子筛对钙离子的吸附符合Langmuir等温模型。更多还原

【Abstract】 As natural silicoaluminate mineral, Kaolin is very rich in China. In this paper,4Amolecular sieve is prepared by adding the aluminum source in the process ofhydrothermal synthesis process with Metakaolin which is made with raw materials. Theprocess is simple and the possibility of enlarging the scale of production becomesaccessible. This paper has great value in industry such as in green，deep process ofKaolin，cutting the costs of the synthesis of molecular sieve, broadening the applicationsof molecular sieve，and so on。By adopting single-factor experiment, the most appropriate temperature and time forcalcining can be respectively measured as800℃and2h during the calcining process. Byanalyzing the phase, structure and appearance of kaolin through different measures, suchas DSC, XRD, FT-IR, SEM, the results showe that, after calcining, the kaolin is finallytransformed into Metakaolin which features high whiteness, low impurity content, smallparticles and high reactivity.By adopting Single-factor experiment during the hydrothermal synthesis process, theoptimum process conditions are determined: n(SiO2)/n(Al2O3) is1.9; n(Na2O)/n(Al2O3) is2.4; n(H2O)/n(Na2O) is50；alkalization temperature is50℃; alkalization time is3h;crystallization temperature is90℃and crystallization time is6h.Through testing the properties and characterizing the structure of the sample whichis made in the optimized conditions. The results show that all the prosperities of4Amolecular sieve that is composted in this experiment are in line with national standards:pH is10.6, ignition loss is22%, static saturated water absorption is21%, and the contentof calcium ion adsorption is up to335mg/g (CaCO3). After analyzing the sample in themethods of DSC, XRD, FT-IR, SEM etc, the results show that the4A molecular sievecontains zeolite water structure which owns good thermal stability, its heat resistancetemperature can be reached to800℃, the sample is in cube crystal shape with intactgrowth; Its crystal are small particles with uniform distribution; and with high purity andcrystallinity.In the last part, we discuss the influences of various conditions on the calcium ionadsorption of4A molecular sieve. The results show that the best adsorption condition is:pH is10, temperature is40℃，time is60min in100ml solution with0.15mol/L initial solution concentration of Ca2+, when the usage of4A molecular sieve is1g, theadsorption of calcium ion can be reached to172mg/g.With the fixed pH, the calcium ionadsorption of4A molecular sieve is in accordance with the Langmuir molecularabsorption Isothermal model.更多还原