Al2O3对稀土尾矿微晶玻璃结构和性能的影响

采用熔融法制备了以白云鄂博稀土尾矿为主要原料的微晶玻璃。利用DTA、XRD、SEM等现代分析手段,系统地研究了Al2O3含量对稀土尾矿微晶玻璃的析晶温度、主要晶相、晶体结构、晶粒大小、密度和耐酸碱腐蚀性能的影响。结果表明:稀土尾矿微晶玻璃的主晶相为透辉石和钙长石;随着Al2O3含量的升高,稀土尾矿微晶玻璃的初始析晶温度逐渐升高、晶体粒度变大、析晶困难、析晶率降低;微晶玻璃的表观密度、抗折强度、耐酸性呈现出先升高后降低的趋势,而耐碱性呈现先降低后升高的趋势。Al2O3的含量在6.43%时,抗折强度最大为200.11MPa。     

钽铌尾矿在烧结微晶玻璃中的应用研究

通过大量实验 ,研究了钽铌尾矿在烧结法微晶玻璃装饰板中的应用。确定了 Ca O— Al2 O3— Si O2 系统玻璃颗粒的起始烧结温度 ( Ts) ,起始析晶温度 ( Tc)。利用 X射线衍射分析 ( XRD)和扫描电子显微镜 ( SEM) ,对晶化试样的物相进行鉴定和微观结构观察。研究结果表明 ,钽铌尾矿可以作为烧结法生产微晶玻璃的原料 ,并且可以得到主晶相为β-硅灰石的微晶玻璃。     

热工制度对铁尾矿微晶玻璃的晶化行为及机械性能的影响研究

本文利用北京某地区高硅型铁尾矿研制建筑用微晶玻璃板材，引入适量的晶核剂使玻璃中产生晶化。重点探讨热工制度对铁尾矿微晶玻璃的晶化行为及机械性能的影响研究。主要借助的研究手段有差热分析(DTA)、X衍射仪(XRD)、显微硬度仪及扫描电镜(SEM)。     

晶化制度对矿渣微晶玻璃析晶行为的影响作用研究

以铁尾矿、硼泥和粉煤灰为原料,采用熔融法工艺制备微晶玻璃,借助XRD、SEM和显微硬度等测试方法,研究了晶化制度对微晶玻璃结构和性能的影响。试验结果表明:随着晶化温度的升高和晶化时间的延长,微晶玻璃中主晶相均为辉石相,且随着晶化温度的升高和晶化时间的延长,晶体尺寸逐渐增大,而微晶玻璃的表观体积密度和显微硬度呈升高后降低的趋势。     

利用正交法优化掺杂La2O3微晶玻璃的热处理制度

实验在前期研究工作基础上选择了稀土氧化物La2O3,采取外加法对Li2O-Al2O3-SiO2(LAS)系统微晶玻璃进行掺杂,为了寻找掺杂La2O3后LAS系统微晶玻璃的最佳热处理制度,采用正交试验设计,对试样在不同温度下进行了热处理,并对晶化后各试样进行了各项性能测试并对测试结果进行了分析,结果表明:热处理制度对微晶玻璃的各项性能影响显著,其中又以晶化温度的影响最大;综合各项性能后,得到合适热处理制度为590℃/1 h→790℃/2 h,此时,试样的力学性能和热膨胀性能最好,其抗折强度为141 MPa,热膨胀系数为1.26×10-7℃-1(20～400℃).     

石棉尾矿微晶玻璃装饰板材的研制

介绍了以石棉尾矿为主要原料制造微晶玻璃。包括原料制备、熔制、成型、退火和晶化等工艺。重点探索了尾矿掺入量以及微晶玻璃的熔制、成型、热处理等制度。利用ＤＴＡ、ＸＲＤ等研究了该系统玻璃的析晶性能。     

矿渣微晶玻璃热处理制度的优化设计

以白云鄂博矿二次选后尾矿、粉煤灰和石灰石为主要原料,采用熔融法制得矿渣微晶玻璃.利用正交实验方法研究了热处理工艺参数对矿渣微晶玻璃抗弯强度的影响,得到影响因素的主次顺序为:晶化时间＞核化温度＞晶化温度＞核化时间,确定最优热处理制度为:核化温度700℃,核化时间2h;晶化温度850℃,晶化化时间2h.并利用XRD、SEM、EDS检测手段对制得的微晶玻璃显微结构进行了分析.     

CaO-MgO-Al2O3-SiO2系铜尾矿微晶玻璃析晶特征研究

以铜尾矿为主要原料,采用压延法开展玻璃熔制实验制备CMAS系基础玻璃,进行玻璃微晶化及稳定性等方面的研究.利用差热分析(DSC)、X衍射分析(XRD)、扫描电镜(SEM)等方法系统研究了微晶玻璃组分、热处理温度和时间等因素对玻璃析晶的影响.完成了以透辉石(Ca(Mg,Al)(Si,Al)2 O6)为主晶相的微晶玻璃制品实验配方及制备工艺方案,确定了热处理制度为900℃保温2 h的最佳工艺参数,制备的微晶玻璃力学性能优于市场同类产品.     

S~(2-)+F~-复合晶核剂制备铁尾矿微晶玻璃的研究

以河北省承德地区的铁尾矿为主要原料,以Ca O-Mg O-Al2O3-Si O2系统微晶玻璃作为配方的依据,选用S2-+F-复合晶核剂,采用熔融法制备透辉石晶相的微晶玻璃。经过DTA、X射线衍射仪、耐磨测试仪分析和测试该微晶玻璃的结构与耐磨性能,结果符合微晶玻璃的耐磨性指标。为低成本规模生产铁尾矿微晶玻璃做了部分技术准备。     

白云鄂博尾矿微波还原除铁制备CAS系微晶玻璃工艺研究

利用“微波还原-磁选”除铁后的白云鄂博尾矿制备了CaO-Al2 O3-SiO2 (CAS)系微晶玻璃.借助差热分析、扫描电子显微镜和X射线能谱分析研究了CAS系微晶玻璃经680℃核化后不同晶化温度(870～930℃)对其析晶行为、显微形貌和性能的影响.结果表明:此CAS系微晶玻璃相组成随晶化温度的升高由长石相转变为辉石相,同时微晶玻璃中晶体形态逐渐长大,由方块状小颗粒微晶发育成板条状以及大颗粒的雪花状和方块状的“骨架”微晶;而且适当提高晶化温度有利于微晶玻璃的烧结致密化,进而提高其力学性能,900℃晶化处理的微晶玻璃抗折强度和密度分别为181.2 MPa和3.1 g·cm-3,而且其耐酸碱性能很好.本研究对于开发微晶玻璃新产品、新工艺有重要的指导意义.     

CaO-Al2O3-SiO2系统微晶玻璃的冲蚀磨损研究

CaO-Al2O3-SiO2系统微晶玻璃装饰板材是一种新型建筑装饰材料。本文利用冲蚀磨损实验研究了影响CaO-Al2O3-SiO2系统烧结法微晶玻璃装饰板材磨蚀行为。讨论了微晶玻璃组成、结构、磨粒粒径、冲蚀角、冲蚀时间对CaO-Al2O3-SiO2系统微晶玻璃的冲蚀性的影响。结果表明:随着微晶玻璃中晶相含量的增加,磨料对其表面的冲蚀磨损量明显下降。微晶玻璃的冲蚀量随冲蚀角的增大、冲蚀时间的增长、磨粒粒度的增大而增加。     

我国利用尾矿和工业废渣生产微晶玻璃研究进展

近年来,我国在利用尾矿和工业废渣生产微晶玻璃研究上取得了长足进步,为减少工业废弃物排放、保护环境做出了很大贡献,综述了我国在利用尾矿和工业废渣生产微晶玻璃上的研究进展。     

Effect of sintering temperature on solidification and migration of non-volatile and volatile heavy metals in glass-ceramic

Using tailings as material to prepare glass-ceramic is an excellent way to achieve the resource utilization of solid waste. However, at present, researches on the solidification and migration of heavy metals are limited. Therefore, in this study, ten groups of samples were prepared by controlling sintering temperatures. The solidification, migration, and leaching behavior of non-volatile and volatile heavy metals were studied. The research showed that, with the increase of temperature, the properties of the samples were improved. Fe participated in the phase transformation and evolved into insoluble iron pyroxenes solid solution, while Pb was homogeneously distributed in the glass matrix of glass-ceramics. The leaching concentrations of Fe and Pb in the glass-ceramics were 0.055 mg/L ～0.087 mg/L and 0.074 mg/L ～0.140 mg/L, which were far below the threshold value. The results showed that heavy metals can be effectively solidified in glass-ceramics and have good environmental benefits.     

Preparation of double-layer glass-ceramic/ceramic tile from bauxite tailings and red mud

Double-layer glass-ceramic/ceramic tiles made from bauxite tailings and red mud were prepared using a single firing powder processing route. The influence of the preparation method used for the green bodies on the microstructure and mechanical properties of the final products was investigated. The macroscopic appearance, microstructure, and mechanical properties indicated that the production of double-layer glass-ceramic/ceramic tiles may be an attractive method for recycling industrial waste into building materials.     

自洁净微晶玻璃的制备工艺研究

为了制备表面具有高疏水性的自洁净微晶玻璃,文中首先以高炉矿渣和钾长石为原料制成微晶玻璃坯体,然后利用溶胶-凝胶的工艺制备出硅溶胶/聚四氟乙烯(PTFE)有机/无机镀液,利用浸渍提拉法在微晶玻璃表面进行镀膜,最后通过热处理制成表面具有自洁净功能的微晶玻璃。分析了乙醇用量、加水量、pH值、陈化时间及温度对于溶胶形成的影响,以及硅溶胶/PTFE配比对于镀液性能和镀膜效果的影响。利用XRD、SEM、接触角测定仪等对样品进行性能检测。结果表明,制备的微晶玻璃的主晶相是镁黄长石,聚四氟乙烯对硅溶胶有良好的修饰作用,自洁净微晶玻璃的接触角已达到120°,具有较强的疏水性。     

Pressureless sintering of bioverit® iii/ti particle biocomposites

A new bioactive material, based on Bioverit® III glass-ceramic (B3), was synthesised: it is a composite material (named B3T) having a glass-ceramic matrix and titanium particles as toughening phase. The aim was to toughen the Bioverit® III glass-ceramic, already successfully tested by in vivo experiments. The B3T biocomposite, reinforced by 15 vol% Ti particles, was prepared by pressureless sintering, starting from Bioverit® III base glass powders. The sintering conditions were carefully optimised by using differential scanning calorimetry and hot stage microscopy. On the basis of this study a low temperature viscous flow sintering process was chosen, and high density glass-matrix composites were obtained. A further crystallisation, using the temperature and time conditions for bulk Bioverit® III glass ceramic, was performed to obtain a glass-ceramic matrix/Ti particle composite. A qualitative mechanical characterisation revealed toughening benefits in the Ti additions. An in vitro test (fibroblast growth) was performed on the composites in order to demonstrate their biocompatibility. ©     

Dissolution of a Sphene Glass-Ceramic, and of Its Component Sphene and Glass Phases, in Ca-Na-Cl Brines

Leaching experiments for up to 569 d have been performed to examine the dissolution in Ca-Na-Cl groundwater of a sphene (CaTiSiO₅)-based glass-ceramic, a candidate material for immobilizing nuclear fuel recycle wastes. The experiments involved leaching of samples of a simulated-waste-loaded glass-ceramic, doped with ²²Na or ⁴⁵Ca, in a synthetic groundwater at 25° and 100°C. The results are compared with those from separate leaching experiments with ²²Na- or ⁴⁵Ca-doped samples of aluminosilicate glass and ceramic sphene, representing the component phases of the glass-ceramic. The comparison supports a model in which the glass-ceramic dissolution rate may be approximately derived from the weighted average of the separate dissolution rates of its component glass and ceramic phases. No synergistic effects in the leaching of the glass and ceramic phases in the glass-ceramic were found.     

Scintillating glass-ceramic substrates for indirect flat panel detectors in digital radiography

Indirect flat panel detectors (I-FPDs) enable digital radiography at high X-ray energies. However, the performance of these devices is limited due to the large number of X rays that pass through them undetected. The authors hypothesize that a glass-based scintillator may serve as a substrate for the thin film transistors and photodiodes in an I-FPD, leading to improvements in X-ray detection for improved performance. The authors synthesized a series of five glass-ceramic scintillators based on an oxyhalide glass matrix. Each glass ceramic contains barium chloride crystals which serve as scattering centers to prevent “light trapping” in the material; barium chloride is also a well-known scintillation crystal. Four of the samples contain trivalent terbium, which serves as a second luminescent center. The light output of each sample was compared against a well-known X-ray scintillator, gadolinium oxysulfide (GOS) under RQA9 exposure conditions, in the back-irradiation configuration. The addition of terbium oxide to the glass composition increases the detected light output, which varies by concentration. The thickness of the glass-ceramic scintillator has a profound effect on performance, with the results influenced by such factors as self-attenuation of emission in the thicker samples and decreased X-ray capture in the thinner samples. The brightest sample tested achieved a light output 13% that of the GOS intensifier screen. The results indicate that the use of scintillating glass-ceramic substrates should lead to increased performance in indirect digital radiography.     

冷却工艺对CaO-Al2O3-SiO2系微晶玻璃强度及热膨胀性能的影响

将某一固定组成的CaO-Al2O3-SiO2系玻璃烧结到一定温度后,采用不同的冷却工艺得到若干试样。通过X衍射分析、抗折强度和热膨胀系数的测定,研究了冷却温度制度对CaO-Al2O3-SiO2系微晶玻璃强度及热膨胀性能的影响。研究发现随着微晶玻璃的起始冷却温度逐渐升高,试样的抗折强度逐渐提高,热膨胀系数逐渐减小。     

Intermediate-Temperature Environmental Effects on Boron Nitride-Coated Silicon Carbide-Fiber-Reinforced Glass-Ceramic Composites

The environmental effects on the mechanical properties of fiber-reinforced composites at intermediate temperatures were investigated by conducting flexural static-fatigue experiments in air at 600° and 950°C. The material that was studied was a silicon carbide/boron nitride (SiC/BN) dual-coated Nicalon-fiber-reinforced barium magnesium aluminosilicate glass-ceramic. Comparable time-dependent failure responses were found at 600° and 950°C when the maximum tensile stress applied in the bend bar was 60% of the room-temperature ultimate flexural strength of as-received materials. At both temperatures, the materials survived 500 h fatigue tests at lower stress levels. Among the samples that survived the 500 h fatigue tests, a 20% degradation in the room-temperature flexural strength was measured in samples tested at 600°C, whereas no degradation was observed for the samples tested at 950°C. Microstructure and chemistry studies revealed interfacial oxidation in the samples that were fatigued at 600°C. The growth rate of the Si-C-O fiber oxidation product at 600°C was not sufficient to seal the stress-induced cracks, so that the interior of the material was oxidized and resulted in a strength degradation and less fibrous fracture. In contrast, the interior of the material remained intact at 950°C because of crack sealing by rapid silicate formation, and strength/toughness of the composite was maintained. Also, at 600°C, BN oxidized via volatilization, because no borosilicate was formed.