Improvement of Mullite and Magnesia‐Based Refractory Castables Through Addition of Nano‐Spinel Powder

Two different commercial refractory castables based on mullite or magnesia aggregates have been improved through addition of 0–25 wt.% nano‐magnesium aluminate spinel (MA) powder. Physico‐mechanical and refractory properties were tested at different firing temperatures. The phase composition, thermal analysis, and microstructure of these refractory castables were detected using X‐ray diffraction (XRD), differential thermal analysis (DTA), as well as scanning electron microscope (SEM) attached with energy dispersive X‐ray unit, respectively. The castable sample mix containing 10 wt.% nano‐MA spinel powder was chosen as an optimum composition according to its good sintering, mechanical as well as refractory properties.     

阻燃剂氢氧化镁的研究和开发进展

介绍了阻燃剂氢氧化镁的特性、阻燃机理,制备方法以及改性技术进展,指出了今后的发展方向。     

Detrital Mg(OH)2 and Al(OH)3 in Microwaved Hydrotalcites

Microwave irradiation power (90, 180, 270 or 360 W) determines the composition and the structure of the compounds obtained when pH is increased, decreased or maintained constant during preparation. Although in all cases the X-ray diffraction patterns show that the obtained compounds are hydrotalcite-like, the surface areas (40 up to 240 m²/g) as well as other microcrystalline compounds have to be inferred, such as Al(OH)₃ or Mg(OH)₂.     

Mg(OH)2及其与红磷复配阻燃聚丙烯复合材料的性能研究

研究了Mg(OH)2和Mg(OH)2/红磷复配体系阻燃聚丙烯材料的性能,选用热塑性弹性体POE对阻燃聚丙烯复合材料进行了增韧改性,结果表明:Mg(OH)2与红磷复配可以减少Mg(OH)2用量,降低对材料力学性能的损耗;POE较好地改善了材料的冲击性能,其添加量为15份时,材料的冲击强度可由8.14kJ/m2增大至12.83kJ/m2。最后利用锥形量热仪验证了Mg(OH)2/红磷复配体系的协同阻燃效应。     

无机阻燃剂氢氧化镁的研发进展

综述了无杌阻燃剂氢氧化镁的研发进展，重点介绍了钛酸酯和硬脂酸（盐）表面改性、微胶囊化和控制氢氧化镁的形态，如镁盐晶须的制备等，并指出发展方向是改性氢氧化镁与其他阻燃剂协同使用。     

ATH和MH对木塑表面防火涂层性能的影响

采用偶联剂对氢氧化铝(ATH)和氢氧化镁(MH)进行表面改性处理,并将其应用于木塑复合材料的环氧树脂基表面防火涂层中.通过显微镜、红外光谱和热失重分析等手段研究了表面处理前后的ATH和MH及其填充量和两者的不同配比对防火涂层的防火性能影响.结果表明:与未经表面改性处理的ATH和MH相比,其经表面改性处理后更有利于提高防火涂层的防火性能;当经钛酸酯偶联剂处理的ATH用量为120份时,表面涂层的防火性能最好;经硅烷偶联剂处理的MH的最佳用量为50份;当ATH/MH质量比为2∶1时,防火涂层的防火性能最好,其耐燃时间达到了527 s.     

Development of New Cordierite‐Based Refractory Coatings for Casting Applications

In this study, new refractory coatings based on synthesized cordierite for the casting applications were developed. The investigation included starting raw materials characterization, synthesis of the cordierite, design of the refractory coating as final product, and its application testing. The obtained results pointed out that coating suspension sediment stability was crucial quality parameter. Design and optimization of the coatings composition, with controlled rheological properties included, were achieved by application of different coating components, namely different suspension agents and by alteration of the coating production procedure. Cordierite, used as filler, was obtained by means of synthesis in the solid‐state reaction on the basis of talc, kaolin, and alumina. The investigation showed that the application of these particular types of water/alcohol‐based coatings has positive influence on surface quality and structural and mechanical properties of the castings of aluminum alloys obtained by casting into sand molds by means of evaporable models method, that is, evaporate pattern casting process.     

无机镁铝阻燃剂及其应用发展趋势浅析

论述了无机氢氧化铝、氢氧化镁阻燃剂的作用机理 ,重点从超细 (粒径达 1～ 5 μm)、表面处理 (采用偶联剂对阻燃剂表面进行化学处理 )、复合 (利用化学共沉淀法制备出一种Al(OH) 3·6Mg(OH) 2 ·4.5H2 O复合阻燃剂 ) 3个方面分析了阻燃剂的阻燃性能的优劣及其应用发展前景     

氢氧化镁粉体的表面改性研究

主要研究了氢氧化镁的湿法表面改性的工艺过程，用浊度分析方法对改性效果进行了比较，确定了最佳工艺条件。实验结果表明：最佳改性剂为硬脂酸钠，改性剂用量为6％（质量分数），改性温度为85℃，改性时间为20min。同时，最佳条件下改性样品的红外光谱分析表明：最佳改性条件下，硬脂酸钠有效包覆在氢氧化镁粒子表面，使氢氧化镁表面有机化，增强了氢氧化镁粉体与有机体的亲和性，这对于制取添加型的氢氧化镁阻燃剂具有指导意义。     

Energetics of Silica‐Poor Glasses in the Systems MgO–SiO2 and Mg0.5Ca0.5O–SiO2

A series of alkaline‐earth silicate glasses, with compositions ranging from the metasilicate to the ortho‐ and suborthosilicate, have been synthesized by aerodynamic levitation and CO₂ laser melting. They have been studied by high‐temperature oxide melt solution calorimetry with 2PbO·B₂O₃ as solvent. The enthalpies of formation from the oxides at room temperature () have been calculated from the solution enthalpies. Glasses in the Ca_0.5Mg_0.5O–SiO₂ system show greater energetic stability than those in the MgO–SiO₂ system, with a more pronounced negative enthalpy of mixing near the orthosilicate composition. This stabilization may explain why it is possible to prepare glasses poorer in silica (suborthosilicate) in the Ca_0.5Mg_0.5O–SiO₂ system but not in the MgO–SiO₂ system. The thermodynamic observations support earlier structural studies in these systems.     

氢氧化镁的水热改性研究及表征

研究了氢氧化镁工业品在一种新型添加剂作用下的水热改性行为，考察了添加剂体系、反应温度、反应时间、添加剂浓度和填充度等因素对水热产物的影响，并用扫描电子显微镜（SEM）、X射线衍射（XRD）和激光粒度仪等对水热产物进行了表征。发现在填充度为67％、添加剂浓度为3mol／L、反应温度为160℃、反应时间为6h时，可获得六方片状、形貌规整、片较厚、分散性良好的水热产物。     

氢氧化镁阻燃EVAC的流变性能研究

采用熔融共混法制备了Mg(OH)2阻燃乙烯-乙酸乙烯酯塑料(EVAC),并采用毛细管流变仪对其流变性能进行了研究。讨论了温度、剪切速率和剪切应力对熔体表观黏度的影响;研究了黏流活化能与剪切速率的变化规律。结果表明,熔体的表观黏度随温度的升高而降低,随剪切速率和剪切应力的增大而减小;黏流活化能随剪切速率的增大而降低。其非牛顿指数小于1,说明Mg(OH)2阻燃EVAC为假塑性流体。当剪切应力无限小时,由Spencer-Dillon公式外推得到阻燃EVAC的零切黏度。     

热处理温度及其对耐火浇注料热震参数的影响

耐火浇注料通常在现场进行热处理，由于耐火烧注层的厚度，形成了冷热面之间急剧的温度梯度，因而这一过程会导致不均匀的显微结构。在本研究工作中，试样分别在600℃、800℃和950℃煅烧并描述其特性，评价了高铝和莫来石浇注料的热震参数－－R″″和Rst。为了进行比较，事先在1200℃对相同材料的不同试样进行了热处理并在上述温度下描述了其特征。研究表明，对于浇注筑衬的炉壁，显微结构的梯度会导致材料的抗热震性的局部变化。可是一般来说，只有温度梯度才会对预烧砖炉壁的抗热震性能产生一定的影响。     

绿色水处理剂氢氧化镁应用的研究进展

氢氧化镁(氧化镁)被称为绿色安全的废水处理剂,本文评述了氢氧化镁在环境保护方面的研究与应用进展,包括工业废水中铅、铬、镍等重金属离子的去除和酸性废水的中和处理,并列举了氢氧化镁对一些实际废水的良好处理效果,包括其对一些特殊废水如含硼废水和放射性废水的处理效果,最后展望了其在生产和应用方面的发展前景。     

阻燃用Mg（OH）2微胶囊技术

介绍通过微胶囊技术对Mg(OH)2进行表面处理,提高其与高分子材料的相容性及在高分子材料中的分散性,达到提高其阻燃效果,改善高分子材料物理机械性能的目的。     

Al（OH）3和Mg（OH）2阻燃EVA性能的研究

选用形貌、粒径尺寸及分布相近的两种无机阻燃剂氢氧化铝（Al（OH）3）和氢氧化镁（Mg（OH）2），研究了二者用量对乙烯-醋酸乙烯酯共聚物（EVA）复合材料的力学性能和阻燃性能的影响，并比较了添加红磷的复合材料的力学性能和阻燃性能。研究表明：Al（OH）3和Mg（OH）2用量对复合材料性能影响比较相似，随着阻燃剂用量的增加，复合材料的阻燃性能提高，拉伸强度增加，但断裂伸长率下降；通过锥形量热仪数据看出：Al（OH），的点燃时间短，最大热释放速率和平均热释放速率低，火行为指数大，阻燃效果比Mg（OH）2好；红磷的加入对复合材料力学性能影响不大，而对阻燃性能影响较大。Mg（OH）2与红磷复配能提高复合材料的氧指数，但是，从水平和垂直燃烧角度考虑，Al（OH）3与红磷之间的阻燃协效效果更好。     

Understanding the Filler Effect on the Nucleation and Growth of C‐S‐H

The “filler effect”, due to the physical presence of mineral additions in cement, is mainly known to accelerate the hydration of the clinker component. Previously, this was attributed to the surface of the filler providing nucleation sites for C‐S‐H as there is a clear dependence on the surface provided by the filler particles. Our results reveal that the increase in nucleation is quite low compared to the area provided. Based on the isothermal calorimetry experiments and SEM images, we demonstrate that the most important parameter is the interparticle distance. We propose that this is mainly the result of the shearing conditions rather than extra surface available for C‐S‐H as formerly assumed. Quantitatively slag and fly ash behave very similarly to quartz. Limestone, on the other hand, seems also to stimulate C‐S‐H nucleation giving it a higher efficiency in accelerating clinker hydration.     

水热法制备纤维状Mg(OH)2

在常压下、采用液相法制备Mg(OH)2试样,XRD分析表明:合适的碳酸镁的煅烧温度和时间,可获得活性氧化镁.SEM分析表明:采用活性氧化镁为镁源之一,可获得径1～2 μm、长60～100 μm的纤维状Mg(OH)2试样.TEM分析表明:此纤维状Mg(OH)2为单晶体.研究结果表明所填加的氧化镁的活性不同,瞬间生成Mg(OH)2沉淀的聚集成核速率就不同;并进一步影响到反应溶液中Mg-O6八面体生长基元;CaCl2的添加,会影响该生长基元在反应溶液中的扩散速率.     

阻燃剂氢氧化镁的国内研究进展

综述了氢氧化镁的改性方法及其在高分子聚合物材料阻燃中的应用的国内研究进展,介绍了氢氧化镁与其他阻燃剂在阻燃高分子聚合物一同应用时的协同效应。     

氧化镁及氢氧化镁的应用研究进展

对氧化镁、氢氧化镁的应用研究进展做了评述。包括硅钢片涂层,赤潮控制和预防,硫化氢脱除与防腐蚀,无机抗菌剂以及油品添加剂,并探讨了其发展前景。