Na_2O－Al_2O_3－SiO_2系统霞石微晶玻璃机械强度的研究

霞石微晶玻璃是一种高强度的新型无机非金属材料．本文以Ｎａ２Ｏ－Ａｌ２Ｏ３－ＳｉＯ２系统为基础，引入晶核剂和复合澄清剂，经高温熔制和两步热处理制备的霞石微晶玻璃，具有较高的抗压和抗折强度．结果表明，霞石微晶玻璃的机械强度与霞石晶体及试样的结构有关，也与微晶化热处理的时间有关。     

A NEW MINERAL——FLUORBRITHOLITE-(CE)

The new mineral fluorbritholite-(Ce)occurs innepheline syenite,marble xenoliths,sodalite syenite xenoliths andpegmatite dikes at Mont St.Hilaire,Quebec.It is associatedmainly with analcine,microcline,aegirine,zircon,biotite,Pyro-phanite,astrophylite,ancylite,natrolite,monazite etc.The mineral is hexagonal,P6_3/m,with a 9.517 (5) (?),c 6.983(4)(?),c/a 0.7337,v 547.7(8)(?),Z=2.The strongest Xray powder diffraction lines and their relative intensities(visual)are:2.851(100),2.821(30),2.753(30),1.970(20),1.969(30)(for MSH-3).Fluorbritholite-(Ce) crystal is shown prismatic.Its colouris pale yellow,tan,reddish-brown.Streak colourless to palebrown;Lustre adamantine;OPaque to translucent;Hardness 5;Brittle;Cleavage{0001}distinct;Fracture even to conchoidal;Density 4.66(1)(meas) or 4.66g/cm~3(calc.);Non-fluorscent.Optically umaxial(-),ω 1.792 (5),ε1.786(5) in Na light;Nonpleochroic.Electron microprobe analyses correspond to ((Ce_(1.69) La_(1.02)Na_(0.82) Nd_(0.44) Sr_(0.30) Ca_(0.17) Mn_(0.17) Y_(0.09) Pr_(0.06)     

河北金家庄地区长英质碱性杂岩的特征及成因

河北金家庄地区产出的长英质碱性杂岩,由两套岩石组成(早期正长质杂岩和晚期钾长石岩),空间上与超基性岩密切伴生,均受东西向断裂控制。长英质碱性杂岩的岩石化学成分,高SiO_2和K_2O+Na_2O,低FeO,Fe_2O_3和MgO;里特曼指数为7.14～9.75;FeO/MgO为1.73～2.18;稀土总量偏低,无铕亏损;~(87)Sr/~(88)Sr值为0.706;δ~(18)O为8.10‰～10.3‰;熔融包裹体的均一温度为925℃。早晚两期岩石的同位素年龄分别为260Ma和187.5Ma。这套长英质碱性杂岩属幔源玄武岩浆分异的产物。     

霞石正长岩除铁的试验研究

研究了某霞石正长岩的矿物特性,弄清了铁在矿石中的赋存状态。试验结果表明多段干式磁选工艺是除去该矿石中铁矿物的有效途径。当原矿含铁为２．９８％时,通过分选可以获得产率为７４％,含铁量低于０．２％的霞石正长岩精矿     

Phase transition and thermal stability of ceramics from Na-based geopolymers

Geopolymer ceramics undergo a series of thermal phase transitions, progressing from an amorphous geopolymer gel to a crystalline phase, and eventually to an amorphous glass phase as the temperature increases. However, there is a lack of mechanism understanding regarding to the crystallization process and the subsequent thermal degradation. Here, we fundamentally investigated the kinetics of nepheline formation in Na-based geopolymer systems and its thermal stability up to 1400°C. Nepheline crystallization is controlled by bulk nucleation and three-dimensional crystal growth based on the Avrami factor of 4.64, where the activation energy of nepheline formation is 350.59 kJ/mol. High thermal stability of geopolymer ceramics is achieved due to the appearance of nepheline up to 1400°C with the Si/Al ratio ranging from 1.40 to 1.94, while melting and amorphous structure are formed above a higher Si/Al ratio of 2.22. The nature of sintering for geopolymer ceramics consists of shrinkage, expansion and shrinkage corresponding to dehydroxylation, crystallization, and densification, leading to a thermal shrinkage of 21% at 1400°C.     

南江霞石替代长石在瓷砖应用的可行性研究

本文主要研究了纯霞石和霞石与石英混合料的烧结性能特点。另外也分析了霞石替代长石对试样烧结性能和瓷砖的抗折强度的影响。结果表明：[1]霞石烧结温度高于长石。[2]加入一定量的石英对霞石烧结性能有显著的影响。[3]霞石替代长石不仅降低瓷砖烧成温度,对瓷砖抗折强度也有明显的改善。     

豫西嵩县石门铷矿床中隐爆角砾岩的发现及其意义

石门铷矿床位于华北陆块南缘之外方山断隆,矿体赋存于印支期乌桑沟正长岩体内,正长岩主要成分为钠长石、微斜长石,具次生加大现象。通过对矿区新发现的隐爆角砾岩中正长岩进行主量、微量以及稀土元素分析,正长岩具高硅（SiO₂=60%～70%）、贫铁（F₂O₃+FeO=1.89%～5.63%）、高钾（K₂O=10.19%～15.80%）、低钙（CaO=0.09%～1.25%）、低钠（Na₂O=0.06%～0.38%）等特点,研究认为以上地幔物质为主的过碱性流体上侵过程中交代、重熔周围岩石形成的碱交代热液,热液上升至浅地表发生爆炸形成隐爆角砾岩,热液中Rb元素形成的络合物发生分解置换长石和云母中的K,最终累积富集成矿。该矿床为一碱交代热液型铷矿床,外方山地区及外围存在很多类似的碱性岩体,建议加强对此类型矿床的研究与寻找工作。     

霞石正长岩对碱-硅酸反应的影响

以霞石正长岩为代表,研究了含碱集料对碱-硅酸反应膨胀的影响。研究结果表明,80℃或150℃蒸汽养护条件下可快速检测出霞石正长岩对碱-硅酸反应的影响;霞石正长岩在混凝土中的分解反应在增加混凝土可溶碱含量的同时,反应本身还将降低孔溶液OH-浓度,因此由霞石正长岩分解析出的碱与水泥中的碱对碱-硅酸反应影响不同,只有在适当的条件下才能显著增大碱-硅酸反应膨胀。     

Na2O-Al2O3-SiO2-P2O5玻璃的结构和析晶性能研究

采用熔融-淬冷法制备了不同(Al₂O₃+P₂O₅)含量的碱铝硅酸盐玻璃,通过拉曼光谱、X射线衍射光谱、扫描电镜研究了其结构特征和析晶性能。发现随着(Al₂O₃+P₂O₅)含量减少,玻璃中Na₂O含量增加,玻璃化转变温度从685 ℃降低到622 ℃,当减少至摩尔分数为22%时,出现析晶峰且起始析晶温度降低。拉曼光谱表明Q⁴_P对应的拉曼峰强度变低且逐渐向低波数方向移动,说明Na₂O作为网络修饰体使硅酸盐玻璃结构逐步解聚,玻璃的析晶能力逐渐增强。结果表明:当(Al₂O₃+P₂O₅)摩尔分数为22%时热处理后的样品存在晶型转变,700 ℃热处理时以NaAlSiO₄霞石晶体为主,900 ℃时转变为以Na_6.8Al_6.3Si_9.7O₃₂霞石晶体为主。当(Al₂O₃+P₂O₅)的摩尔分数为21%和20%时,热处理后的样品能稳定析出Na₃PO₄和Na_6.8Al_6.3Si_9.7O₃₂晶体。热处理后的样品析出了耐酸侵蚀性较差的富磷相和Na₃PO₄晶体,导致化学稳定性变差。