【作者】 孙建勋；

【导师】 林润雄；

【作者基本信息】 青岛科技大学 ， 材料学， 2009， 硕士

【摘要】 论文在综合分析国内外有关制备沸石分子筛的原料的选择、制备方法和应用基础上,运用现代材料分析技术对实验室制备的白炭黑和4A分子筛等进行了全面系统的研究,主要内容如下:氟硅酸是磷矿石生产磷肥过程中的副产有害废物,对环境造成严重的污染,因此氟硅酸的开发利用急需解决。目前,氟硅资源的开发和利用还不完善。鉴于上述情况,本研究以高浓度氟硅酸溶液为原料,通过两步氨化法得到高品质白炭黑和高浓度氟化铵溶液。研究了加料方式、反应时间、搅拌强度、洗涤方式等工艺条件对白炭黑质量的影响规律。从而确定了第一步氨化的优化条件为:加料方式碱滴加酸;原料浓度20%氟硅酸、13%氨水;反应时间10min;反应温度40℃;搅拌转速1000rpm;氨水用量220g;洗涤方式采用pH=9.3稀氨水(质量浓度为0.001%)。第二步氨化的优化条件为:反应终点pH值为9.5;反应时间50min;反应温度50℃;搅拌转速260rpm;陈化时间60min;陈化转速150rpm。该技术工艺流程简短,主流程共两步反应四步洗涤过滤;反应效率高,设备利用率高;反应条件温和,可在常温完成反应,能耗较低;操作弹性大,可对白炭黑的比表面积和DBP吸收值进行调控。4A分子筛是目前最常用的代磷助剂。比较常规的4A分子筛相比较,超细4A分子筛具有更优异的性能,但关于超细4A分子筛的制备还不系统。鉴于上述情况,本研究采用实验室制备的白炭黑,补加铝源,采用水热法制备了超细4A分子筛产品。深入讨论了钠硅比、水钠比、晶化时间和晶化温度对4A分子筛的影响,确定了制备超细4A型分子筛的最佳工艺参数,硅铝比为2.0、钠硅比为1.0、水钠比为40、晶化温度为90-95℃和晶化时间为6h,并通过X射线衍射(XRD)、扫描电镜(SEM)和红外(FT-IR)等分析手段进行了表征,结果表明:产品结晶度较高;形状规则、大小均匀、分布范围较窄;平均粒径较小;钙离子交换容量为328-340mgCaCO3/g4A分子筛,白度平均为95%,完全满足洗涤助剂的要求,同时对于充分利用我国的自然矿物资源,保护环境,发展我国自己的绿色材料均具有特别重要的意义。更多还原

【Abstract】 On basis of integrated analysis of a great deal of literatures and data about the selection of raw materials, preparation methods and applications, this paper entirely and systematically studies on the synthesis of silica and zeolite 4A in the laboratory by using of modern material testing and analysing techniques. The main contents of the paper is as follows:Fluorosilicic acid is the hazardous waste by-product in the production of phosphate fertilizer progress and it has a serious impact on enviroment, so how to develop and utilize it need to be adressed urgently. At present, the development and utilization of the fluorosilicone resources is not perfect. In view of the above,this paper prepares the silica and the high concentrations of fluoride ammonium solution through two-step ammoniation using high concentrations of fluorosilicic acid solution,studies the feeding mode, reaction time, stirring intensity, washing conditions and so on, which has the great impact on quality indicators of the products. So the study determines the optimal conditions of the first step for amination as follows: feeding methods is dropping alkali to acid ; the concentration of materials are silicate fluoride of 20% and ammonia of 13%; reaction time is 10min; reaction temperature is 40℃; stirring speed is 1000rpm; ammonia dosage is 220g and the Washing liquid is ammonia with pH value of 9.3(mass concentration of 0.001%) ; the optimal conditions of the second step are as follows: the pH value of reaction end point is 9.5; reaction time is 50min; reaction temperature is 50℃; stirring speed is 260rpm; agining time is 60min;agining speed is150rpm.The technology has excellent advantage,such as brief process, the main progress containes two-step reaction process and four-step filtration; high efficiency, high capacity utilization of equipments; mild reaction conditions and low energy consumption,which could be completed at room temperature; operate flexibly which could control Silica Specific surface area and DBP absorption.4A molecular sieve is most commonly used agent on behalf of phosphorus. Comparing with the conventional 4A molecular sieve, Ultra-fine 4A molecular sieve has more excellent performance, but the preparation of ultrafine zeolite 4A system is not pecfect. View of the above, the ultra-fine 4A molecular sieve is hydrothermally synthesized using aluminum source and silicon,which is from silica preparation in the laboratory.The work studies the depth discussion of the sodium-silicon ratio, water-sodium ratio, crystallization time and crystallization temperature on the impact of 4A molecular sieves and determines the best process parameters in the preparation of Ultrafine Zeolite 4A.These parameters are that silicon-aluminum ratio is 2, sodium-silicon ratio is 1.0, water-sodium ratio is 40, the crystallization temperature is 90-95℃and the crystallization time is 6h.The products are characterized by XRD,SEM,FT-IR,and so on.Results demonstrate that the crystallinity of the products is high, the shape of the product is in rules, which has uniform and single size,the distribution of normal distribution is narrow and small, the calcium exchangeability of the products is 328-340mg CaCO3/g dried 4A molecular sieve and the whiteness is 95%.So the products are more suitable to be used as detergent builder.At the same time,the technology is particularly important because it can make full use of our natural mineral resources,protect environment and develop our own green materials更多还原