Absorption Spectra of Sodium Aluminate Solutions

The absorption spectra of sodium aluminate solutions have been examined at different concentrations. As a result, it was found that the characteristic absorption band due to aluminate ion shows a λ_max at 265–270 mm?.     

铝酸钠溶液的鲁米诺增强声致发光研究

Ultrasonic processing on sodium aluminate solutions was proved to have effects on the gibbsite crystallization process from sodium aluminate solution. In order to investigate the mechanism of the ultrasonic intensification, the sonofluorescence spectrum was detected by fluorescence spectrometer in sodium alumiante Luminol solutions, and the spectrum under the conditions of various ultrasonic power and different composition of sodium aluminate solutions were studied. It is found that the sodium aluminate Luminol solution can irradiate fluorescence by ultrasonic processing above the given power; the intensity of sonofluorescence are relatively low in sodium aluminate solutions with high concentration and low αk（mol ratio of Na2O/Al2O3 in sodium aluminate solution）. The relationship between the sonofluorenscence and ultrasonic intensification on gibbsite crystallization process from sodium aluminate solutions were also discussed. The conclusion that the ultrasonic effects are influenced by ultrasonic cavitation and intensity of sonofluorescence spectrum is deduced.     

铝酸钠溶液中析出一水软铝石过程的宏观动力学

对铝酸钠溶液中析出一水软铝石过程的宏观动力学进行了研究.在考虑主要影响因素的前提下,提出了动力学模型,并通过线性回归计算出方程的参数,给出了相应的动力学方程.研究结果表明:分解反应对A l2O3过饱和度和游离NaOH浓度的反应级数分别为2.24和-2.24,前者与大多数研究者的结论一致,而后者则说明溶液中游离NaOH是对反应影响较大的动力学制约因素;反应的表观活化能为62.248 kJ/mol.     

超声场强化铝酸钠溶液种分过程的理论研究

采用半经验量子化学计算方法AM1,计算了超声场作用下铝酸钠溶液中可能存在的各类铝酸根离子、自由基以及它们之间发生反应的可能产物的热力学生成焓和前线轨道数据.根据计算结果,分析了各种可能反应的热力学趋势;并在此基础上对热力学趋势较大的反应运用前线轨道理论进行了成键可能性分析.结果表明,超声场作用下产生的自由基促进了铝酸钠溶液中Al(Ⅲ)配位数的增加并形成生长基元单体Al(OH)4-(H2O)2,同时自由基并不迅速被消耗,因此,超声场可以促进工业上铝酸钠溶液的分解过程.     

Studies on the Anionic Species of Sodium Aluminate Solutions

Raman, UV, IR and NMR spectra, activity measurement and quantum chemical calculation methods are used concurrently to study the anionic species of sodium aluminate solutions. It has been found that sodium aluminate solutions with the same composition but different preparative histories may exhibit quite different optical andNMg spectra.Sodium aluminate solutions contain a series of aluminium-containing anions including Al(OH)_4~-,Al(OH)_6~(3-) and [(HO)_3Al-O-Al(OH)_3]~(2-).They may convert into each other but the reactions may be rather slow,so that solutions with the same composition but different preparative histories may have different ratios between various anions, and exhibit different spectroscopic properties.     

铝酸钠溶液中苛性碱全碱的自动分析

本文采用流动式微量自动滴定技术，选择以磺基水杨酸、氯化钡、酚酞的混合液为载流滴定剂，滴定苛性碱；再以磺基水杨酸和酚酞的混合 液为载流滴定剂，滴定苛性碱和碳酸碱一半的合量。     

铝酸钠和含硅铝酸钠溶液结构和性质的研究

本文通过对铝酸钠和硅铝酸钠溶液的红外光谱、拉曼光谱、粘度、表面张力、丁达尔现象和聚沉等光谱和物理化学性质的研究测定,分析了硅在铝酸钠溶液中的行为.认为硅主要是取代Al-O-Al结构中的Al,形成Al-O-Si结构和Al-O-Si-O-Al-O结构等多种形式硅氧铝键以及由氢键相连的大分子结构.这种结构直接影响其物理化学性质,表现为随硅含量增加表面张力增加,粘度上升,具有丁达尔现象等.说明含硅铝酸钠溶液中存在大分子的胶性基团,属于无机高分子溶液,这种网络状"大分子"结构是硅铝酸钠溶液稳定的原因.     

Determination of Gallium By Liquid-Liquid Extraction-Flame Atomic Absorption Spectrometry In Bayer Process Aluminate Solutions

Abstract

The described flame-atomic absorption determination of gallium involves the extraction of 8-hydroxyauinoline-Ga complex and the extraction of galhum as an ion association complex from strong hydrochloric acid into Methyl Isobutyl Ketone (MIBK). Both of the examined extraction systems were found to be workable for gallium determination in aqueous solutions. A comparison of mentioned extraction systems showed that only the second one can be applied for gallium determination in low concentration in aluminate solutions (strong alkaline). Finally, an analytical scheme for gallium determination in aluminate solutions is recommended (extraction of Ga from hydrochloric acid solutions, 3.0-50M, through matrix matched calibration curve). the proposed procedure was found to be simple, selective and accurate.     

苛性碱、碳酸碱和全碱的同时流动注射分析

采用流动注射滴定技术实现了氧化铝生产过程中铝酸钠溶液中苛性碱、碳酸碱和全碱的同时自动分析。以磺基水杨酸为载流,它既为滴定剂又是铝的掩蔽剂;酚酞和甲基橙混合液为试剂流,它们是苛性碱、碳酸碱和全碱的指示剂。该法可测定６．２～３０．９ｇ／Ｌ的碳酸碱和３．１～１５．５ｇＬ的苛性碱（均以Ｎａ２Ｏ计）,测定速率３０个样／ｈ,标准标准偏差小于０．５％（ｎ＝１１,Ｎａ２Ｏ＝２１．９４ｇ／Ｌ）。     

过饱和铝酸钠溶液中氢氧化铝自发成核动力学规律的研究

用电导法和吸光光度法首次对苛性比相同的不同浓度过饱和铝酸钠溶液自发分解过程进行了实时跟踪研究,获得铝酸钠溶解氢氧化铝自发成核动力学方程,探索了H₂O和Na⁺对氢氧化铝自发成核过程的影响.结果表明,过饱和铝酸钠溶液分解为氢氧化铝属化学反应控制过程;H₂O参与了溶液分解过程控制步骤的反应;K⁺和Na⁺等阳离子参与了溶液的重构,但对溶液分解的控制步骤影响不大.     

Investigation into the ageing process in gels of gelatin/water systems by the measurement of their dynamic moduli

Summary During the ageing (renaturation) process of 1–5% aqueous gelatin solutions the dynamic moduli were measured in the temperature range from –1.2 °C to 25.2 °C. The renaturation process appears to be strongly dependent on concentration, temperature and thermal history. The process at 25.2 °C appears to be of 3rd order, whereas the rate determining step appears to be the aggregation of mono helices into triple helices.

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Zusammenfassung Während der Alterung (Gelierung, Renaturierung) von 1–5% Lösungen von Gelatine in Wasser wurden deren Speicher- und Verlustmoduln in einem Temperaturbereich von –1,2 °C bis 25,2 °C gemessen. Der Alterungsprozeß hängt stark ab von der Konzentration, der Temperatur und der thermischen Vorgeschichte. Die Ordnung des Prozesses bei 25,2 °C ist drei und der geschwindigkeitsbestimmende Reaktionsschritt ist die Aggregation von monohelices in Tripelhelices.

     

Investigation into the ageing process in gels of gelatin/water systems by the measurement of their dynamic moduli

Summary This second paper on the ageing of aqueous gelatin gels (1–5%) deals with the mechanism of the renaturation process. The maximum gelation temperature, i. e. the gel temperature, increases with increasing concentration. For the heat of cross-linking a value of H° = - 442 kJ/mol was found, corresponding with mono-helices of 24 windings and a length of 230 Å. The influence of the thermal history is considerable, and the heat of activation of the rate determining step is very small. Hence, the temperature dependence of the degree of ageing is not caused by temperature dependence of the reaction rate constant, but by the increase in stability of small structures which accompanies a decrease in temperature.

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Zusammenfassung Diese zweite Veröffentlichung betreffs der Alterung von 1–5% Lösungen von Gelatin in Wasser behandelt den Mechanismus des Renaturationprozesses. Die maximale Gelierungstemperatur, d. h. die Geltemperatur, nimmt zu mit zunehmender Konzentration. Für die Verknüpfungswärme wurde gefunden H° = -442 kJ/mol. Dieser Wert korrespondiert mit Monohelices von 24 Windungen und einer Länge von 230 Å. Die Abhängigkeit von der thermischen Geschichte ist bedeutend und die Aktivierungsenergie des geschwindigkeitsbestimmenden Reaktionsschrittes ist sehr klein. Demnach wird die Temperaturabhängigkeit des Alterungsgrades nicht verursacht durch die Temperaturabhängigkeit der Reaktionsgeschwindigkeitskonstante, sondern durch die Zunahme der Stabilität kleiner Strukturen mit abnehmender Temperatur.

     

电导法研究过饱和铝酸钠溶液均相成核过程

采用自行研制电导在线跟踪仪, 配套特制的传感器式电导电极, 研究铝酸钠溶液均相成核过程中溶液电导变化规律, 及溶液过饱和度对反应诱导期作用; 通过测定铝酸钠溶液均相成核过程诱导期, 结合溶液均相成核理论, 测得323 K下, 饱和度S>3.8的铝酸钠溶液均相成核过程中的表观反应级数n=4±1, 固-液界面能γ=(40.6±2.0) mJ·m-2, 并据此估算临界成核粒径rc=(1.1±0.2) nm. 研究结果与文献值吻合, 证明该套仪器具有较高的灵敏度和可靠性.     

Radon and radium activity concentration measurement in drinking water resources in Kurdistan Region-Iraq

Journal of Radioanalytical and Nuclear Chemistry - In this present research, twenty-five drinking water samples were collected in Erbil Governorate in the Iraqi Kurdistan Region and analyzed for...     

On-stream measurement of heavy water concentration by intermediate neutron moderation

A method of measuring heavy water concentration is described based on intermediate neutron moderation. With a 1.6 g²⁵²Cf neutron source and a BF₃ proportional counter, for 500 ml samples, accuracies of the measurements are within ±0.02 mol% in the concentration range of 0100 mol% with 210 minute counting. To evaluate the practical effectiveness of the method, a model apparatus was built for routine use in laboratory and on-stream measurements. It was successfully applied to observe the substitution process between light water and heavy water in an ion exchange resin tower at a nuclear power station.     

恒推动力条件下研究铝酸钠溶液种分过程晶体长大动力学

在铝酸钠溶液的种分过程中,往往利用间歇式反应器来研究晶体的长大动力学,由于受实验过程条件的变化及成核和小粒子附聚的影响,实验结果往往不令人满意.本实验研制了一种新型装置,它能保证实验过程反应条件基本不发生变化,且能有效避免成核和小粒子附聚对实验结果的影响.实验证明,用它来研究铝酸钠溶液种分过程晶体的长大动力学可以得到较为满意的效果.实验研究了Nk=170g.l-1,αk=1.52～2.01,T=65～75℃条件下,铝酸钠溶液种分过程晶体长大的速率表达式为G(L)=k0×β2×exp(Ea/RT).其中,k0=2.058×1011μ m.h-1,与溶液的温度和浓度无关;反应的活化能Ea=67.301KJ.mol-1;β=(1/α k-1/αk*)表示溶液的过饱和度,α k、α k*分别为铝酸钠溶液的苛性比和平衡苛性比.