助熔剂改善粉煤灰高温熔炉的温度和流动性研究

采用CaO,Fe2O3以及石灰石、硫酸渣助熔剂按不同比例与粉煤灰混合,对煤灰熔点的影响进行试验研究.结果表明,在还原性气氛下,添加适量CaO和Fe2O3可使粉煤灰熔点下降,当CaO添加率超过40%时反使灰熔点急剧上升;石灰石、硫酸渣中起助熔作用的成分是其中的CaO和Fe2O3,其助熔行为与分析纯CaO和Fe2O3基本一致     

钙镁复合助熔剂对长平煤灰熔融特性影响研究

以高灰熔融温度长平煤为对象,分别向其中添加单助熔剂CaO、MgO和钙镁复合助熔剂,在高温还原性气氛下,分别利用X-射线衍射仪(XRD)、扫描电子显微镜-能谱仪(SEM-EDX)研究钙镁复合助熔剂对煤灰熔渣晶体矿物转化过程、微观形貌和微区化学组成的影响,揭示钙镁复合助熔剂的助熔机理.结果表明:添加6％钙镁复合助熔剂(WCao/WMgo=1),可将煤灰熔融温度降至1297℃,且助熔效果优于单助熔剂CaO、MgO;煤灰熔融过程中,离子半径较小的Ca2+、Mg2+容易进入空隙中,引起硅酸盐结构重组,分别形成架状硅酸盐钙长石、岛状硅酸盐镁橄榄石、镁堇青石等;钙长石与镁橄榄石等镁质矿物之间低温共熔体的生成,是钙镁复合助熔剂能够显著降低煤灰熔融温度的主要原因.     

酸碱比值与助熔剂对煤灰熔融流动温度影响的研究

以我国62组重要商业用煤的煤灰化学成分和灰熔融性为研究对象,讨论了酸碱比值与灰熔融流动温度的关系,结果表明酸碱比值越大,流动温度越高。考察了助熔剂CaO和Fe2O3不同添加量对6组高灰熔点煤灰熔融流动温度的影响。实验表明:同一煤样中添加相同质量的助熔剂CaO和Fe2O3,对酸碱比值的改变相同,但是其助熔效果不同,因此酸/碱比值不可当做衡量煤灰熔融特性的唯一参数。以6种煤的实测数据为基础,对助熔剂CaO添加量的经验公式的准确性和适用性作了分析。由于煤种的多样性与灰成分的复杂性,使得经验公式具有局限性,助熔剂添加量的确定仍需实验测量。     

助熔剂对Eu~(2+)掺杂的碱土金属硅酸盐荧光粉发光性能的影响

研究了不同助熔剂对Eu2+掺杂的MgO·2SrO·SiO2发光性能的影响。结果表明:加入3%(质量分数)BaF2作为助熔剂时样品发光效果最好。对400nm紫外光激发下样品的发射光谱进行了Gauss拟合,出现了3个发光中心。采用van Uitert提出的Eu2+5d激发态带边位置与配位数的经验公式进行计算,认为3个发光中心是由Eu2+分别取代Sr(Ⅰ)格位、Sr(Ⅰ)格位附近形成的杂质束缚激子态和Sr(Ⅱ)格位形成的。晶体场强度与X—O键长成反比,随着掺入助熔剂阳离子半径的增大,发射光谱发生了红移。     

助熔剂对高灰熔点煤影响的实验研究

对山西两种高灰熔点煤添加不同比例的CaO和Fe2O3助熔剂后的熔融特性及其在高温下的矿物质行为进行了实验研究,用X射线衍射观察分析了不同温度下的煤灰矿物组成变化.结果表明,在弱还原性气氛下,两种助熔剂均可有效降低煤灰熔点,但不同的助熔剂对不同煤灰熔点降低的效果不同.当在煤灰中添加适量助熔剂时,煤灰熔点可达到最低,这是由于煤中矿物质在高温下与CaO,Fe2O3发生反应,最终形成低熔点共熔物,从而使得煤灰熔点下降.     

助熔剂对型煤灰熔融特征温度的影响

研究了高灰熔点型煤灰成分与灰熔融特性的关系,考察了Fe2O3, MgO, CaO和固体水玻璃助熔剂对型煤灰熔融温度的影响. 结果表明,碱性氧化物与灰中所含矿物质在高温下易形成低共熔混合物,能有效降低型煤灰熔融温度. 加入等量(11%, w)的MgO, CaO及固体水玻璃、Fe2O3,流动温度分别下降了22.0, 58.8, 81.2和91.9℃. 通过三元相图及XRD分析揭示了物相组成变化和矿物晶体的存在形式. CaO, 固体水玻璃和Fe2O3适宜的添加量分别为11%, 9%和9%. CaO和固体水玻璃对型煤还具有粘结和促进气化作用,更适合作为助熔剂.     

配煤、助熔剂对毕节煤灰熔融特性温度的影响研究

为提高毕节地区煤炭气化和燃烧的性能,研究了配煤和助熔剂对毕节煤灰熔融性温度的影响。在毕节地区织金煤、修文煤和金沙煤中,分别按一定比例添加CaO、Fe_2O_3两种助熔剂,并在织金煤中选用高灰熔融性温度的煤与低灰熔融性温度的煤相配,来测定添加助熔剂和配煤对煤灰熔融特性温度的影响。研究结果表明:CaO添加比例从3%到12%,煤样的灰熔融性温度先降低后增大;Fe_2O_3添加比例从5%到20%,煤样的灰熔融性温度始终呈下降趋势,Fe_2O_3助熔效果较好;低灰熔融性温度的煤与高灰熔融性温度的煤相配,能有效降低高灰熔融性温度煤的灰熔融性温度。     

助熔剂对甲基磺酸盐镀锡板性能的影响

研究了甲基磺酸盐体系镀锡生产中两种不同的助熔剂对镀锡板耐蚀性和涂装性能的影响。结果表明:对耐腐蚀性能而言,无机盐类助熔剂明显优于烷基磺酸类助熔剂。与采用烷基磺酸类助熔剂时相比,由于采用无机盐类助熔剂形成的钝化膜量略高,且其中热稳定性较好的组分Cr2O3较多,因此漆膜与其镀锡板的附着性能略好,但因钝化膜中Cr(OH)3偏低而抗硫性略差。镀锡板生产前需要综合考虑用户对产品的功能要求来选择适宜的助熔剂。     

助熔剂在甲基磺酸电镀锡生产中的应用

先分析了助熔剂在镀锡板软熔中的作用机制,接着对比了采用不同助熔剂和脱盐水助熔对镀锡板性能的影响.结果表明,目前没有一款助熔剂能够兼顾镀锡板的外观和耐蚀性,因此对实际生产中的机组进行改进,以适应镀锡板的差异化助熔工艺,效果良好.     

氯化物助熔剂对Y3Al5O12:Ce3+荧光粉性能的影响

选用卤化物LiCl、NaCl、KCl和SrCl2等作为助熔剂,合成了一系列YAG∶Ce粉体,并研究了助熔剂对YAG∶Ce荧光粉晶相、形貌和发光性能的影响.结果表明适量助熔剂有利于YAG∶Ce荧光粉的晶化,合成的荧光粉具有石榴石的结构,规则的形貌和窄的粒度分布.添加适量助熔剂可以提高YAG∶Ce荧光粉的发光强度.最适宜的添加量分别是:LiCl 10%,NaCl 7%,KCl 7%,SrCl,4%.     

The peculiarities of N2O activation over oxides of alkali-earth metals in the oxidative coupling of methane

The catalytic properties of Na/CaO with a low amount of alkali promoter and SrO were studied under comparable conditions, using CH₄-O₂ and CH₄-N₂O reaction mixtures. CH₄ conversion was similar for both oxidants ( <5%). Nitrous oxide was shown to be more active and selective oxidant than oxygen. It was noted that molecular oxygen influenced the rate of N₂O decomposition over SrO, while for Na/CaO catalysts such effect was not observed. Two different schemes for N₂O decomposition over catalysts studied were found. Carbon dioxide decreases the production of ethane over SrO when N₂O is used as an oxidant.     

Reduction of Eu3+ to Eu2+ in Aluminoborosilicate Glasses Prepared in Air

Eu₂O₃-doped aluminoborosilicate glasses were prepared in air at high temperature. Luminescence measurements were used to investigate a valence change from Eu³⁺ to Eu²⁺ ions in the aluminoborosilicate glasses. The results showed that the doped Eu³⁺ ions were partially reduced to Eu²⁺ in the Eu₂O₃:RO–Al₂O₃–B₂O₃–SiO₂ (RO=CaO, SrO, BaO, Li₂O) glasses, but not in the Eu₂O₃:RO–Al₂O₃–B₂O₃–SiO₂ (RO=Na₂O, K₂O) glasses. The changes of Eu reduction with different RO components were discussed with the variation of optical basicity of RO and with different valency of R cations. The effects of co-doping BaO and ZnO in aluminoborosilicate glasses on Eu reduction were also investigated and discussed.     

低铋环保型无铅釉上彩熔剂的研究

在碱-硼-硅系统基础熔剂中引入外加剂,通过多种碱金属、碱土金属及外加剂等复合效应来代替铅在熔剂中的作用进而研制低铋环保型无铅熔剂。并通过对试样进行化学稳定性、热膨胀性、光泽度、堆烧、粘度测试、印花彩烤等一系列对比实验考察所用外加剂对熔剂性能的影响。实验结果表明:在基础熔剂配方的基础上外加剂氧化铋、氧化镧、氧化钼、氧化钨的外加量分别控制在5%,1%,1.25%,1%时即可满足熔剂各种性能要求。     

Orange- and Violet-Emitting Long-Lasting Phosphors

Orange phosphorescence from Eu³⁺-activated CaO and SrO and violet phosphorescence from Pb²⁺-activated SrO were clearly observed after the materials had been excited with ultraviolet light. The orange phosphorescence resulted from ⁵ D ₀ to ⁷ F ₁ transitions of the Eu³⁺ ions and the violet from ³ P ₀ to ¹ S ₀ transitions of the Pb²⁺ ions. The phosphorescence lasted >1 h. Trapped-electron centers and hole centers introduced into the CaO and SrO hosts by the ultraviolet light appear to have been responsible for generating the long-lasting phosphorescence.     

高包容模拟放射性核素Sr固化技术研究

以氧化铁、钛粉、氧化钙、二氧化钛为原料,利用溶胶-凝胶反应制备了人造钙钛矿岩石。以人造岩石为基底,利用固相反应固化模拟放射性核素Sr。借助X射线衍射(XRD)、扫描电子显微镜(SEM)等方法分析固化体形貌与结构。结果分析表明:当Fe2O3∶Ti∶CaO∶TiO2=2∶3∶4∶1(物质的量之比),掺入SrO含量为10%时,可以获得较好的钙钛矿物相。     

Thermal behavior,structure, crystallization and solubility of the melt-derived SiO2–P2O5–Na2O–F-MO (M = Ca,Sr, Zn) glasses

In this work, phospho-silicate glasses with SiO₂–P₂O₅–Na₂O–F-MO (M = Ca, Sr, Zn) composition were prepared by using the conventional melt quenching technology. Structural, physical, and chemical property tests were used to analyze the effects of different SrO and ZnO content on the structure and properties of the glasses. The results showed that the glass stability varied nonlinearly as CaO was replaced by SrO, which was mainly related to the different positions of Sr²⁺ and Ca²⁺ ions breaking the network connection in the network structure, and the substitution of ZnO for CaO led to a continuous decrease in the stability of the glasses. The immersion experiment showed that SrO doping was more feasible than ZnO doping to improve the biological activity of the glasses, and the doping of ZnO promoted the dissolution of ions in the glasses. The obtained results indicated that the glass samples prepared in this paper have potential biological activity, which has potential applications in dental treatment.     

CaO含量对铝硼硅玻璃理化性能的影响与机理

以SiO2、B2O3、Al2O3及碱土金属氧化物(MgO、CaO、SrO)为原料,利用高温熔融法制备无碱铝硼硅玻璃。研究不同CaO含量对无碱铝硼硅玻璃性能和结构影响作用规律。对玻璃进行了热综合分析(DSC)、耐化学稳定性和密度的性能测试,通过红外光谱(FTIR)和X射线光电子能谱(XPS)对玻璃试样进行网络结构分析。研究表明,玻璃的析晶区间面积随着CaO含量的增加,由3.7 J/g升高到15.03 J/g,[AlO6]和[BO4]的出现会导致玻璃网络结构疏松,玻璃的析晶倾向增强;玻璃的被酸侵蚀由3.6817 mg/cm2增加到4.2609 mg/cm2,玻璃被碱侵蚀由1.4199 mg/cm2降低到1.0907 mg/cm2,碱侵蚀的过程中生成的一层硅酸钙薄膜阻碍了反应的进行;随着CaO含量的增加,玻璃中的非桥氧含量增加,会促使[AlO4]向[AlO6]转变,CaO含量继续增加还会使[BO3]向[BO4]转变。     

Synthesis,Characterization and <Emphasis Type="Italic">In Vitro</Emphasis> Biological Evaluation of Sol-gel Derived Sr-containing Nano Bioactive Glass

In this study, bioactive glass of the type SiO₂–CaO–SrO–P₂O₅ was obtained by the sol-gel processing method and the effects of SrO/CaO substitution on the in vitro biological properties of the synthesized glasses were evaluated. The obtained bioactive glasses were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), differentioal scanning caloremetry (DSC) and Brunauer, Emmett and Teller (BET) analyses. The effects of various glass compositions on proliferation and differentiation of osteoblastic cells were also evaluated. The results showed that incorporation of Sr in the obtained glass network did not result in any structural alteration due to the similar role of SrO compared with that of CaO. In vitro experiments with human osteosarcoma cell lines (MG-63) indicated that bioactive glass incorporating 5 mol % in the composition revealed optimal cell proliferation and alkaline phosphatase (ALP) activity. Our results ascertained this material to be non-toxic and compatible for the proposed work in segmental defects in the rabbit model in vivo.