【作者】 王舰；

【导师】 宁桂玲；

【作者基本信息】 大连理工大学 ， 化学工艺， 2010， 博士

【摘要】 硼化合物是无机盐工业的一个重要产品系列。多年来,相关的产品开发和理论研究一直是国内外研究的热点,特别在航空航天等高科技领域,受到了特别关注和重视。硼酸是硼化合物中应用最广泛的一种,不仅在于它自身的功能价值,更在于它是合成多数含硼功能产品的基本原料。然而,硼酸中的杂质及其含量限制了它的使用范围。更受限于国内硼酸纯化技术的缺陷,目前国内核工业和光学材料等一些特殊用途的硼酸基本依赖进口。考虑到我国是硼资源大国(其储量占世界各国储量的第5位),而辽宁省的硼资源位列全国第一,本文以国家和辽宁省的硼资源发展战略思想为依据,开展硼酸纯化及含硼功能材料合成研究。论文的主体框架结构是：以工业硼酸为原料,以光电级专用硼酸为目标,针对硼酸中所存在的金属杂质开展硼酸的定向纯化研究,在此基础上,结合本课题组高纯铝醇盐先进合成技术,开展高纯硼酸铝晶须及硼酸铝基发光材料的合成研究,解决其中的关键技术及技术基础问题,为提升硼酸和含硼材料使用性能,以及拓宽其应用领域提供技术支撑和理论依据。具体研究内容结果如下：1.采用络合-结晶法对工业硼酸进行定向纯化研究。基于化学溶度积和络合平衡理论,利用硼酸在不同温度下溶解度梯度和结晶特性,提出一种络合-结晶纯化技术。以光电级专用硼酸的纯度和杂质指标为指导,研究了络合剂种类、用量和溶剂体系等对硼酸中杂质脱除效果的影响；研究了结晶方式、结晶温度、结晶时间等工艺条件对杂质表面吸附或夹带的控制作用。实验采用电感耦合等离子体原子发射光谱(ICP-AES)、紫外-可见吸收光谱(UV-Vis-IR)对产品进行表征。通过实验数据归纳和理论分析形成了络合-结晶联合重结晶脱除硼酸中铁杂质技术体系,纯化后硼酸的铁含量从100μg/g降到1μg／g以下；硼酸纯度从98.7%提升到99.9%以上。该技术已在成都某企业得到应用,用于生产特种光学玻璃专用高纯硼酸。2.基于高纯硼酸和高纯铝醇盐制备硼酸铝晶须的研究。传统硼酸铝晶须均以无机铝源和硼酸、氧化硼等为原料制备。本文用异丙醇铝代替无机铝源,除了考虑到异丙醇铝的易溶胶化和易超细特性外,还考虑到原料纯度差异。在此基础上研究了硼酸铝晶须的生成反应规律和结晶特性。深入探讨了铝硼(Al／B)的摩尔比、前驱体的煅烧温度、煅烧时间等工艺条件对于硼酸铝晶须生长中的晶型和形貌的影响规律。同时,为了形成比较,也考察了传统无机铝源(氧化铝)以及分析纯硼酸作为反应原料的情况。通过热重-差热分析(TG-DTA)、X-射线衍射(XRD)、傅立叶变换红外光谱(FT-IR)、扫描电镜(SEM)、透射电镜(TEM)等表征手段对产物的结构和性质进行了分析。结果表明,原料的高纯度可以提高产物表面的洁净度以及保持维度的一致性,用铝醇盐和高纯硼酸代替无机铝源和分析纯硼酸可以降低硼酸铝晶须的直径,增大长径比。通过实验设计得到制备硼酸铝晶须的最优条件。在此条件下得到的Al18B4O33晶须的直径为200～400 nm,长度为8～10μm,长径比大于10。本研究为下面的稀土掺杂硼酸铝基荧光体的制备提供基础。此外,针对目前高温固相法合成硼酸铝晶须反应温度过高的问题,尝试了燃烧法制备硼酸铝晶须,通过设计合理的化学反应,实现了以尿素作为燃烧剂低温合成硼酸铝(A118B4O33)晶须,比传统高温固相法的反应温度降低200℃,为合成硼酸铝晶须的研究提供了新思路。3.稀土掺杂硼酸铝基质荧光体的合成与性能研究。分别采用Al18B4O33晶须离子包覆法和凝胶纳米包覆法制备了Eu3+和Tb3+双掺杂Al18B4O33荧光体,考察了样品的形貌特征及发光性能。与Al18B4O33晶须离子包覆法制备的荧光体相比,凝胶纳米包覆法制备的荧光体形貌更为均一有序,发光强度更强。因此本论文主要围绕以高纯硼酸和高纯异丙醇铝为反应物,凝胶纳米包覆法制备Eu3+和Tb3+双掺杂Al18B4O33荧光体展开研究。深入探讨Al／B的摩尔比、前驱体的煅烧温度、煅烧时间等工艺参数对Al18B4O33:Eu3+,Tb3+荧光体发光性能的影响。同时,为了比较原料纯度对发光材料发光性能的影响,制备了以普通硼酸和传统铝源(氧化铝)为初始原料的荧光体。结果发现,原料的纯度对荧光体的发光性能有显著影响,高纯度可以获得更强的发光强度。Eu3+和Tb3+共掺Al18B4O33荧光体是由晶态和无定形态组成的,Eu3+和Tb3+掺杂属于非晶格掺杂。而在Al／B=1：1的条件下,通过比较Eu3+和Tb3+共掺Al18B4O33与Eu3’单掺Al18B4O33的发射光谱,发现共掺样品中Eu3+的红色发光显著增强,说明在荧光体中,存在着Tb3+到Eu3+能量传递。此外,为了实现稀土离子Eu3+、Tb3+对硼酸铝基质的晶格掺杂以期提高发光效率及色纯度,采用凝胶纳米包覆法合成了Eu3+、Tb3+激发GdAl3(BO3)4高纯超细红色和绿色发光材料。实验着重研究了Gd3+的浓度对Al2O3-B2O3二元体系的晶体结构及发光性能的影响,以确定性能最优的荧光粉。结果发现,随着Gd3+浓度的增大,Al2O3-B2O3二元体系由正交晶系Al18B4O33过渡到六角晶系GdAl3(BO3)4,同时GdAl3(BO3)4的晶相含量增大,而且Gd3+对Eu3+和Tb3+的发光具有敏化作用,Gd3+还具有一定的猝灭浓度。更多还原

【Abstract】 Boron compounds are an important series of products in the inorganic salts industry. The relative of products development and theory researches have become a hot topic, especially in the high tech domains, such as the Aerospace etc for many years. Boric acid is widely used in the boron compounds, not only its functional value, but also it is an essential raw materials for the synthesization of boron functional products. However, the impurities of boric acid has been limited its range of use, but also greatly limited the purification technology of boric acid in the domestic. Currently, some special purposes boric acid, such as optical materials and so on, basically depends on imports in the domestic markets. Considering our country owns massive boron resources (storage level stands third in the world), this dissertation, that is based on the national and liaoning province’s boron resources developmental strategy, develops the removal of iron impurties of boric acid and the synthesis of aluminoborate functional materials. The main frame construction of dissertation is that:To take industrial boric acid as raw material develops the removal of iron impurties of boric acid which takes electro-optical level special-purpose boric acid as target. Based on this, it combines high pure aluminum alkoxide to research on the synthesis of aluminum borate whiskers and its fluorescence materials which solved key technologies and the technology based question, to promote boric acid and containing boron functional materials performance, as well as expands its application domains to provide the technical supports and the theory basis. The results are listed below:1. Use the complexation-crystallization method to conduct the directional purification of boric acid. Based on chemical solubility product and complexing balanced theory, the purified technology of complexation-crystallization, which applies the different solubility of boric acid at different temperature and crystal characteristic, has been proposed. The experiment has studied the types of complexant, amounts and solvent systems etc to affect the removal of iron impurities of boric acid, also studied technical conditions such as crystal temperatures, crystal ways, crystal time to control surface absorption or smuggles of impurities. ICP-AES, UV-Vis-IR adsorption were used to characterize the products. Having formed technical system of the complexation-crystallization method to remove iron impurities of boric acid through the experimental datum induction and theoretical analysis, the iron content of boric acid reduces from 100ug/g to lug/g; the purity of boric acid increases from 98.7% to 99.9%. Simultaneously, calcium, chromium, cobalt, nickel, titanium, copper imprities have been removed. This technology has been used to produce the special optical glass in chengdu some enterprise.2. To base on high pure boric acid and high pure aluminum alkoxide as reactants study the synthesis of aluminum borate whiskers. The traditional aluminum borate whiskers have been used inorganic aluminum sources, boric acid and boron oxide etc as raw materials. The dissertation, that studys formative reaction rule and crystal characteristic of aluminum borate, besides the consideration of the characteristic of raw material purity, replaces the inorganic aluminum sources with aluminum isopropoxide and combine solated superfine characteristic of aluminum isopropoxide, simultaneously, considering traditional aluminum source to form the comparison. Experimental study focused on the aluminum borate whiskers to control the crystal structure and morphology to grope the optimized synthetic method of aluminum borate whiskers. The technical conditions such as, molar ration Al/B, calcination temperature, calcination times, different aluminum sources, etc, which have affected the crystal structures and morphology formation, have been systematically investigated. TG-DTG, XRD, FT-IR, SEM, TEM were used to characterize the products. The results showed that high-purity raw materials can improve the cleanliness of the products surface and maintain the consistency of dimensions, replacing the traditional inorganic aluminum sources with the aluminum alkoxide can reduce the diameters of aluminum borate whiskers, increasing the aspect ration. In the optimal synthesis conditions, the whiskers are very neat and straight with an diameter ranging from 200 to 300nm and lengths ranging from 3 to 5μm, aspect ratio is greater than 10. This research provides the foundation for the following the synthesis of rare earth doping in aluminoborate.In addition, in view of the high temperature synthesis of aluminum borate whiskers by solid state reaction, combustion synthesis of Al18B4O33 Whiskers has been demonstrated through a rational chemical reaction, which realized the low temperature synthesis of Al18B4O33 Whiskers by urea as combustion agent. Comparing to the high temperature solid state reaction, combustion method reduces the reaction temperature 200℃to provide a new idea for the synthesis of aluminum borate whiskers research.3. Synthesis and characterization of rare earth doped aluminum borate phosphor. Al18B4O33 Whiskers ion-coating and gel nano-coating methods are synthesized Al18B4O33:Eu3+,Tb3+ phosphors, respectively. Comparing with Al18B4O33 Whiskers ion-coating method, gel nano-coating method abtainning products have a more uniform appearance and more luminous intensity. Therefore, this dissertation mainly focuses on the gel nano-coating method to synthesize Al18B4O33:Eu3+,Tb3+ phosphors. Considering traditional aluminum source to form the comparison and the technical conditions such as, molar ration Al/B, purity of raw materials, calcination temperature, calcination times, etc, which have affected Al18B4O33:Eu3+,Tb3+ phosphor luminescence intensity. The results showed that high purity of raw materials can increase the luminous intensity of the product and traditional inorganic aluminum salts are replaced with aluminum alkoxide to solve agglomeration disadvantages of high temperature solid state method. The fluorophor coexists the crystal phase Al18B4O33 and the aluminoborate glass phase and Eu3+, Tb3+ ions are incorporated into aluminobarate glass phase. When the molar ratio Al/B is equal to 1:1, it found that the emission spectra of Eu3+,Tb3+ co-doped Al18B4O33 samples significantly enhance the red light, indicating the phosphor existence of Tb3+ to Eu3+ energy transfer by comparing the Eu3+,Tb3+ co-doped Al18B4O33 with Eu3+ single-doped Al18B4O33.In addition, It uses gel nano-coating method to synthesize Eu3+, Tb3+ excitation GdAl3(BO3)4 high-purity ultra-fine red and green phosphors, basing on structural diversity from the realization of rare-earth ions Eu3+, Tb3+ doping aluminum borate crystal substrate to improve luminous efficiency and color purity. Experimental study focused on the Gd3+ concentration to affect the binary system Al2O3-B2O3 crystal structure and luminescence properties to determine the optimal performance of the phosphors. The results showed that Al2O3-B2O3 binary system turned into the hexagonal GdAl3(BO3)4 from the orthorhombic Al18B4O33, while GdAl3(BO3)4 crystal phase content increased with the increasing of Gd3+ content. Moreover, Gd3+ has the sensitization to Eu3+ and Tb3+ luminescence, Gd3+ also has a certain degree of quenching concentration.更多还原