玻璃中铁着色的结构分析及配位场理论探讨

从铁离子的电子层结构、玻璃结构及配位场理论对含铁玻璃中铁的着色机理进行了理论分析,指出了铁离子着色的本质所在,并对不同氧化还原条件下铁离子着色状态及其影响因素进行了探讨,给出了较为合理的解释.结论认为铁酸亚铁结构造成含铁玻璃的着色,二价铁与三价铁在不同条件下的转换修正了着色.     

Fe~(2 )、Fe~(3 )在玻璃中配位态的研究

本文用穆斯堡尔谱和分光光度计方法研究了Fe~(2 )、Fe~(3 )在硅酸盐玻璃、硼酸盐玻璃、磷酸盐玻璃中配位状态的变化并用特别方法控制了Fe~(2 )、Fe~(3 )的比值。得到较理想的光谱曲线为在0.8—1.1μm波段透过率<2％,而可见区透过率>80％。根据穆斯堡尔谱的两个主要参数——化学位移及四级劈裂的分析,算出Fe~(2 )、Fe~(3 )在玻璃中的比例,从而分析Fe~(2 )、Fe~(3 )在玻璃中的配位状态。 结果表明,Fe~(2 )在玻璃中主要以六配位形式存在,Fe~(3 )则主要以四配位形式存在。     

以乙二胺为主配位剂的无氰镀铜工艺

研究了铁基体上以乙二胺为主配位剂的无氰碱性镀铜工艺。用正交试验讨论了主配位剂及3种辅助配位剂的用量对镀液的阴极极化曲线、电化学阻抗谱及铜镀层外观、结合力的影响。确定了最佳工艺条件为:乙二胺55g/L,辅助配位剂C30g/L,辅助配位剂T30g/L,辅助配位剂G33g/L。最佳配方镀液的分散能力、覆盖能力均良好,电流效率达80%以上。中试100多件样品的镀层外观及热震试验结合力均合格。在铁基体上用以乙二胺为主配位剂的碱性镀铜工艺代替氰化镀铜预镀是可行的。     

用AlK_α谱线分离法鉴定混合配位化合物中Al的配位状态

利用AlK_α分析Al的配位状态的方法是一种简单而有效的新方法,但在混合配位的情况下,其难点甚多。当前受到普遍重视的方法,是应用非线性最小二乘法对AlK_α进行谱线分离,借此进行各配位成分的定性和定量分析。本文以分析若干化合物中Al的配位状态为例,介绍此方法的原理及其应用。同时,用计算机模拟法对其误差产生的原因及其修正方法作了探讨。结果表明,一般情况下,成分谱线形状的差别将导致显著的定量误差,但用适当的方法修正后可得到满意的定量结果。     

配位滴定法分析双金属氰化物络合催化剂中锌和铁

研究了用配位滴定分析方法测定聚醚多元醇用双金属催化剂中锌、铁含量的方法。以EDTA标准溶液为滴定剂，分别以磺基水杨酸、二甲基酚橙作指示剂，在pH=2和pH=5～6的条件下连续测定铁和锌含量，平均回收率分别为98．84％、99．80％。该方法具有简便、快速、准确的特点。     

利用X射线荧光光谱法研究Na_2O-ZnO-B_2O_3玻璃中Zn的配位状态

利用日本Rigaku X射线荧光光谱仪测定了若干种晶体化合物和玻璃样品的Znkα、Znkβ谱线。分析结果表明:(1)荧光X射线状态分析法可以用于Zn的配位状态的定性分析。(2)六配位Zn的化学位移值往正值方向偏移,四配位Zn的化学位移值往负值方向偏移。(3)玻璃体系中,其各化学组成的变化对位移值没有明显的影响,Znkα、Znkβ谱线的位移主要取决于其Zn——O键长的大小。(4)在Na_2O—ZnO—B_2O_3体系玻璃中,Zn主要为四配位。     

浮法玻璃中铁的价态测试方法

铁是无色透明玻璃中主要有害杂质，而玻璃中铁价态变化，影响玻璃光学性能、热学性能。玻璃中铁价态变化反映玻璃液氧化还原状态，玻璃液氧化还原状态是硫酸盐澄清微泡是否析出重要原因。本文通过对玻璃中铁的价态测试方法进行分析对比，探索浮法玻璃中对铁的价态快速准确测试方法。     

X射线荧光分析测定玻璃中Al~(3+)、Mg~(2+)离子配位状态的探讨

对于x射线荧光分析测定玻璃中Al~(3+)、Mg~(2+)等离子配位状态中存在的问题作了分析,指出了目前的配位数的定性和定量分析理论依据考虑的不足和实际处理中存在的不当之处。对于确定玻璃中铝氧反常微观结构状态化化的Day and Rindone X射线荧光分析实验结果作了分析,认为实验结果的误差及理论上假设的差错不能够推出Al_2O_3/Na_2O摩尔比大于1时,钠铝硅酸盐系统玻璃中多余Al~(3+)以[AlO_6]八面体填充存网络空隙中的结论,并简要讨论了所谓铝氧反常现象及干福熹引入的参数4的客观意义。     

穆斯堡尔谱在钙铁硅铁磁体微晶玻璃研究中的应用

应用穆斯堡尔谱来研究钙铁硅铁磁体微晶玻璃中氧化铁的适宜允许含量、熔制条件、热处理气氛和晶化过程。结果表明,穆斯堡尔谱对于准确地研究钙铁硅微晶玻璃形成、热处理过程中铁离子的价态、配位、结构情况具有重要价值,与XRD等其它方法的研究结果相比可以得到更多的信息。     

Na2O-B2O3-SiO2玻璃结构中硼配位状态的研究

本文主要探讨玻璃熔体在不同的温度处理情况下对硼硅酸盐玻璃结构的影响.通过红外光谱和核磁共振谱分析了硼硅酸盐玻璃在不同温度处理情况下的结构变化.研究结果表明:硼硅酸盐熔体从高温冷却下来,硼配位发生由三角体到四面体的转变,并且硅氧网络聚集导致Q3的含量降低.运用NMR研究温度与硼硅酸盐熔体结构关系发现,高温有利于[BO3]及Q3的存在,反之,低温状态下[BO4]以及Q4的比例更高.     

Surface Analysis of Cr2O3‐, CoO‐, and Al2O3‐Doped Iron–Phosphate Glasses at High Temperature

Surface structures of iron–phosphate glasses were examined using X‐ray photoelectron spectroscopy (XPS). Cr₂O₃, CoO, and Al₂O₃ were introduced to the glass by the replacement of a part of Fe₂O₃, and the simulated fission products are also added. The obtained glasses showed high chemical durabilities by MCC‐1 test. In situ high‐temperature and room‐temperature XPS measurements were conducted on the polished sample surfaces and also those after 1‐week chemical durability test. Unique trends were observed in XPS spectra on heating and after the chemical durability test, respectively. Nature of the glass surface of iron–phosphate glasses was explained from the point of view of surface energy, and the origin of high chemical durability and the effect of chromium ions were discussed based on the changes on surface composition and valence states of transition‐metal ions.     

模拟锶铯废物铁磷酸盐玻璃固化及化学稳定性

研究了铁磷酸盐玻璃固化我国高放废液全分离流程中产出的锶废物及铯废物，熔制了相应的固化体。用XRD，IR测试了固化体的微观结构，用产品一致性试验方法(PCT)研究固化体的化学稳定性。研究表明：在所选的废物包容量范围内可熔制得均质模拟废物铁磷酸盐玻璃固化体，玻璃的主要结构基团为P2O7^4-，均质玻璃固化体有较好的化学稳定性。     

EFFECT OF IRON OXIDE ON MELTING OF GLASS*

The addition of small amounts of iron oxide (0.1 to 0.2%) to soda-lime-silica glass batches exerts a profound influence in increasing the output of glassmelting tanks as well as in favoring the production of higher quality glass. The color produced by this addition, moreover, is not objectionable for many uses of the ware. The accelerated melting rate probably is the result of a chemical effect of iron oxide in the batch and a physical property possessed by such glass to absorb radiation from the flames more efficiently. Attempts to measure these effects were made by rioting the melting rate of glasses which contain varying additions of iron oxide and by determining the temperature gradient that exists in glass when it is melted in a miniature tank. The presence of iron oxide aids melting and fining in crucible melts at 1200°C., but no effect was observed at higher temperatures. The measurement of temperature gradients in a pot holding 45 lb. of glass and heated by flames passing over the glass surface showed that the temperature gradient increases with iron oxide content.     

硫酸盐在玻璃澄清中的若干问题探讨

阐述了硫酸盐在高温玻璃熔体中可能发生的化学反应以及硫酸盐发生热分解反应达到平衡时的平衡常数热力学表达式,讨论了硫酸盐在玻璃熔体中作为澄清剂的澄清机理,介绍了硫在玻璃基体中可能存在的价态以及影响硫在玻璃体中的含量的因素。     

Absorption Spectra of Some Alkali Borate Glasses Containing NiO or Fe2O3 or Mixed NiO + Fe2O3

The absorption spectra of a numbers of alkali borate glasses containing nickel oxide, ferric oxide or both nickel and ferric oxides together were studied to obtain information on their structure. The experimental results were obtained analyzed and explained by assuming that nickel exists in glass as divalent nickel ions in two different states of coordination octahedral and tetrahedral while iron exists in glass as ferric and ferrous states in two different forms, octahedral and tetrahedral according to the amount of the alkali oxide content. It was found that the change in the values of position and intensity of absorption bands may change as the result to the increased d-p orbital mixing which is related presumably to the lower ligand field strength at highest alkali oxide content.     

X-荧光光谱仪压片法测定无碱玻璃化学成分的研究

阐述了无碱玻璃加入粘结剂经混合研磨后,将试样压片成型在X-荧光光谱仪上测定Si、B、Al、Ca、Mg、K、Na、Fe、Ti、F十个化学成分;对试验条件中研磨时间及稀释比的选择进行了讨论,通过对X-荧光光谱仪压片法测定无碱玻璃化学成分的精密度、准确度试验,发现该方法在玻璃纤维池窑作业生产控制中可行。     

Iron transformations during combustion of Pittsburgh no. 8 coal

The chemical speciation of iron in combustion-derived ash is an important factor in determining the likelihood of ash deposit formation and buildup. In this study, the transformation of iron were examined in ash produced by the combustion of a beneficiated Pittsburgh no. 8 bituminous coal under a range of oxygen concentration ranging from 0% to 100% O₂ in a drop tube furnace. The speciation of iron was found to be strongly dependent upon ash particle size, with the lowest fraction of glassy state iron found in the largest ash particles. Both the fraction of iron in a glassy state and the ratio of Fe⁺⁺⁺(glass)/Fe⁺⁺(glass) increased with increasing O₂ concentration in the furnace. For the submicron ash particles, about 10% of the iron is formed by direct disintegration of pyrite and pyrrhotite during combustion. Most of the iron is however, present as Fe⁺⁺⁺(glass), which results from the vaporization, recondensation, and coagulation of iron and silicates. For ash particles with size between 1 and 9 microns, most of the ash derives from mineral coalescence within the reacting char, with additional contribution from extraneous minerals. The fraction of glassy iron in those particles is high because of the high contact probability between iron melt and silicates. For the coarsest ash particles with size greater than 9 microns, extraneous pyrite is changed into hematite, and iron in the core of the char is changed into a glassy state.     

天然玻璃化学成分、结构和物相的无损分析

通过便携式能量色散型X射线荧光、X射线衍射和激光Raman光谱等无损分析技术研究了11块天然玻璃样品的化学成分、结构和物相。结果表明：除两件样品（B1和H3）外,其它样品均为玻璃态,主要化学成分为SiO2与Al2O3。通过化学成分分析可以区分玻陨石和黑曜石样品,玻陨石中铁与碱土金属含量比黑曜石高,而碱金属含量比黑曜石低。激光Raman光谱测试表明：样品在470 cm–1附近有玻璃态特征的弥散包络峰,应为含有6个[SiO4]组成的变形环状结构单元。     

Iron concentration and acceptation of yoghurt prepared in casting iron pots (iron migration and acceptation of yogurt)

Food fortification is an interesting strategy to treat and prevent iron anemia. This study aims to quantify the iron in yoghurt, with gelatin and sugar and without, prepared in iron and glass containers. Sensorial test was use to evaluate the acceptance and preference of the both products. The yoghurt was prepared in containers of iron and glass with UHT milk, powder milk and natural industrialized yoghurt. After fermentation, half of the product received addition of sugar and strawberry flavor gelatin. The collected samples get the total iron quantified by ICP OES. Sensorial analysis involving 105 consumers was use to determine the acceptance and preference of the products. 0,018 and 0,882mg of iron per 100g added in the natural yoghurt prepared in the glass and in the iron pots, respectively. The yoghurt with gelatin presented 0,037 and 1,302mg of iron per 100g when prepared in the glass and in the iron pots, respectively. The preference was low for the yoghurt prepared in the iron pot (29,5%), but when added strawberry gelatin it was about 51,5%. The yoghurt prepared in iron pots, is easily home made and adds important amount of iron. Add gelatin and sugar can favored its consumption.     

Mass transfer of a rising bubble in molten glass with instantaneous oxidation-reduction reaction

The mass transfer around a rising bubble has been studied within the field of glass melting processes. Due to the large value of liquid viscosity, creeping flow was used. The rising bubble is assumed to have a clean interface with a total mobility and the exact solution of Hadamard or Rybczynski was used to define the velocity field around the bubble. The mass transfer of oxygen in the soda-lime-silica glass melt where oxidation-reduction reactions of iron oxides occur is also described.The dimensionless mass transfer coefficient, Sherwood number, was determined as a function of the Péclet number based on the terminal rise velocity of the bubble. Two different techniques have been used: the first based on the boundary layer theory and the second using a finite element method.In order to take into account the oxidation-reduction reaction in a unified framework, a modified Péclet number has been defined as a function of two dimensionless numbers. The first is strongly linked to the equilibrium constant of the chemical reaction and the second is the glass saturation, defined as the ratio of oxygen concentration in the bulk to that at the bubble surface. The Sherwood number, taking into account the chemical reactions, increases with iron content as well as with glass reduction (i.e. small saturation level).From an application point of view, the determination of a modified Péclet number is important because it is possible to use a similar expression (determined without the reaction) by replacing the classical Péclet number by the modified one proposed herewithin.