Kinetics Analysis for the Parallel Reaction of Binary Rare Earth with Tribromoarsenazo

The overall reaction was determined on the basis of the dissociation constant of TBA and the ratio of theligand to the rare earth ion in the complex.The rate law,rate constants and acitivition energies for the reactionof La~(3 ),Gd~(3 )and Ho~(3 )with TBA were studied.It is shown in the study that prerequisites for performingdifferential rate analysis for binary rare earths with TBA are that the pseudo-first-order parallel reactionmechanism should be conformed with,no multinuclear complex would be formed and the co-coloration effectscould be neglected.     

盐酸浸出中低品位胶磷矿中稀土的研究

采用盐酸对贵州织金磷矿进行酸解,研究了盐酸浓度、反应时间、酸料比和温度等对磷矿中稀土浸出率的影响。结果表明,在下述最佳工艺条件下稀土浸出率可达98%以上:浓盐酸(11mol/L)、反应时间120min、酸料比2∶1、温度50℃。     

用盐酸从矿泥中浸出稀土的动力学控制分析

某风化矿泥含稀土在2%～5%,且稀土以氧化物形式存在于矿泥中。用盐酸加热浸取可将稀土浸出,转化为氯化稀土,再用草酸沉淀回收稀土。分析了盐酸浸出稀土的条件和动力学,其速率常数k=(760+0.64×1/ro2)exp(-10500/RT),表观活化能为10.5kJ/mol,是一个典型的内扩散控制过程。温度越高,矿泥粒度越细,越有利于稀土的回收。     

Grey Interrelation Analysis for the Use of Rare Earths and the Elements in Soil in Growing Cotton

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包头稀土精矿添加25%碳酸钠焙烧反应动力学研究

采用XRD、DTA-TG及化学分析等方法,对包头稀土精矿添加25%碳酸钠焙烧反应进行了研究。分解反应分两个阶段进行,第一阶段348℃～455℃,稀土氟碳酸盐分解为稀土氟氧化物,铈被氧化得到CeO     

P204萃取铒的热力学和动力学研究

用含萃取剂P204的磺化煤油对稀土离子Er~（3+）进行萃取平衡研究,得到了萃取平衡式和平衡常数。用恒界面槽测量稀土离子的萃取速率和反萃速率,考察了Er~（3+）浓度、H~+浓度、P204液度和络合物浓度对反应速率的影响,从而得到了反应速率的表达式。提出了界面反模型,用动力学及界面张力实验进行了验证。     

磷酸法中稀土溶出的动力学模型研究

利用磷酸浸出伴生稀土磷矿,研究了温度、时间、酸度、粒度与稀土浸出动力学的关系。结果表明,升高温度、延长反应时间、增大酸度、减小初始粒度均有利于稀土的浸出。界面化学反应控制为稀土浸出的控制步骤,表观反应级数0.993,表观活化能44.6kJ/mol,稀土浸出过程近似为基元反应。按反应核收缩核模型通过统计分析建立了关联温度、浓度、粒度三因素的稀土浸出数学模型。     

Determination of the Rate of CO2–CO Reaction with Magnetite by Isotope Exchange Technique

To clarify the mechanism and get the accurate kinetic parameters of CO₂–CO reaction with magnetite, ¹³CO₂–CO isotope exchange technique was used to determine the rate constants of CO₂ dissociation on the surface of magnetite from 1073 to 1373 K. The real interfacial rate constant was estimated by considering the gas phase mass transfer along a plate. The relationship of the rate constant and CO₂/CO ratio was expressed by the formula of k_c = k₀ (CO₂/CO)^?1?m, m represents the effect of CO₂/CO ratio on the activity of oxygen in iron oxide. The apparent activation energy of the reaction between CO₂–CO gas and magnetite was calculated to 161, 175 ± 15, 198, and 197 ± 16 kJ mol^?1 for CO₂/CO ratios of 4.0, 5.0, 6.0, and 10.0, respectively. This dependence relationship may be caused by the decrease of free electron in magnetite phase with the increase of CO₂/CO ratio.     

Study on the Separation of Rare Earths with the Method of H(DEHP)-Extraction Chromatography

Separation of rare earths was investigated by extraction chromatography where H(DEHP)wasused as a stationary phase,while HCl and H_2SO_4 solutions as a mobile phase.The average separation fac-tors of rare earths,β_(HCl) and β_(H_2SO_4),are 3.79 and 4.57.respectively.The β_(La)~(Ce) in HCl and H_2SO_4 systems areas high as 28.5 and 26.3,respectively.The elution acidity in the study can be down to one tenth and one four-teenth of that in HEH(EHP)system.     

镧热还原氧化钐过程冶金动力学分析

讨论了镧热还原氧化钐过程的动力学环节,分析了还原过程镧—钐合金存在的可能性,采用反证法确定了制备金属钐温度下的动力学控速环节。依据确定的控速环节,很好地解释了相关文献工艺条件实验的结果。     

Calorimetric Studies of the Synergistic Effect: The Reaction of RE(TTA)_3 with N503 in Toluene

Titration calorimetry has been used to study the thermodynamics of reaction in toluene solution of2-thenoyltriflueroacetone(TTA)complexes of rare earths(RE=Y,Nd,Eu,Yb)with N,Ndimethylheptyl-acetamide(N503)at 298.15 K.The heat of the reaction was determined with a TRONACModel 1250 automatic isoperibol calorimeter.The data and figures of titration curve were recorded by the com-puter automatically.An iterative technique of least-square analysis was used to calculate the equilibrium con-stants and the thermodynamic functions including the entropy and free energy changes,minimizing the errorsquare sum by a computer program.     

Structure Reactivity Studies on the Extraction of Rare Earths by Di(2-ethylhexyl)chloroalkyl Phosphonates

The extractive separation properties and the extractive regularity of the lanthanide elements by fivedi(2-ethylhexyl)alkyl phosphonates with various alkyl structure:di(2-ethylhexyl)chloromethyl phosphonateCH_2ClP(O) (OC_8H_(17)-i)_2(1),di(2-ethylhexyl)β-chloroethyl phosphonate ClCH_2CH_2P(O) (OC_8H_(17)-i)_2(2),di(2-ethylhexyl)α-chloroethyl phosphonate CH_3CHClP(O)(OC_8H_(17)-i)_2 (3),and correspondingdi(2-ethylhexyl)methyl phosphonate CH_3P(O)(OC_8H_(17)-i)_2 (4),di(2-ethylhexyl)ethyl phosphonateC_2H_5P(O) (OC_8H_(17)-i)_2 (5),in nitrate system have been studied.The coordination compounds were prepared.The structure of these extractants and their coordination compounds were further explored by IR and ~(31)P NMRspectra.     

Numerical Analysis of the Nb(C,N) Precipitation Kinetics in Microalloyed Steels

Precipitation kinetics of Nb(C,N) in microalloyed steels is crucial for the achievement of favoured steel properties. Therefore, numerous experimental studies have been performed in the past and various theoretical models have been developed to describe Nb(C,N) precipitation. However, the experimental data is sometimes contradictory and even the thermodynamic data for NbC solubility in austenite have a large scatter. In this paper, experimental results on the Nb(C,N) and NbV(C,N) precipitation kinetics in deformed and undeformed austenite are reviewed. Based on these data and with the precipitation kinetics module of the software package MatCalc, computer simulations are performed. The predicted interfacial energy of precipitates is adjusted to match the observed kinetics. A comparison between experimental information and simulation, i.e. time ‐ temperature ‐ precipitation (TTP) diagrams, is drawn and discussed. The results of the computer simulations using modified interfacial energies are in good agreement with the experiments.     

Study on Roast Reaction Kinetics of Baotou Concentrate of Rare Earth with 15% Na_2CO_3 Additions

ＴｈｅｒｅｓｅａｒｃｈｏｎｔｈｅｒｏａｓｔｒｅａｃｔｉｏｎｏｆＢａｏｔｏｕｃｏｎｃｅｎｔｒａｔｅｏｆｒａｒｅｅａｒｔｈｗｉｔｈＮａ２ＣＯ３ａｄｄｉｔｉｏｎｓｂｅｇａｎｉｎ１９６３ａｎｄｔｈｅｉｎｄｕｓｔｒｉａｌｓｃａｌｅｅｘｐｅｒｉｍｅｎｔｓ...     

二安替比林对乙氧基苯基甲烷与锰显色反应的研究

研究了在碱性介质中,空气氧化Ｍｎ（Ⅱ）为Ｍｎ（Ⅳ）后在酸性介质中,Ｍｎ（Ⅳ）氧化二安替比林对乙氧基苯基甲烷（ＤＡｐＥＭ）生成黄色产物,λｍａｘ＝４５０ｎｍ,ε＝１．４９×１０５,锰的含量在０～１０μｇ／２５ｍＬ内符合比尔定律,方法用于钢铁样品中锰的测定,结果满意．     

反相流动注射分光光度法测定稀土铝合金中的稀土总量

本文以二溴—氯偶氮氯磷作显色剂,建立了反相流动注射分析测定稀土总量的方法.实验表明,本方法简便,快速,且钙、铁的允许量较手工法约提高一个数量级.方法用于稀土铝合金中的稀土总量的测定,结果满意.     

三溴偶氮胂与铅显色反应的研究及应用

本文研究了铅与三溴偶氮胂的显色反应,在0.3mol/L的H_3PO_4介质中铅与三溴偶氮胂可生成紫红色的络合物,其最大吸收波长为620nm,表观摩尔吸光系数为3.2×10~4,铅在0～12.5μg/25ml符合比尔定律,已拟出直接光度法测定铜铅合金和粗铜中铅的分析方法。     

P204 萃取Co(Ⅲ)动力学的研究

研究了氨性体系中二 (2 乙基己基 )磷酸 (P2 0 4)萃取Co(Ⅲ )的动力学 ,经过P2 0 412h的萃取 ,Co(Ⅲ )的萃取率为 10 8% ,证实了 [Co(NH3 ) 6]3 是一种动力学惰性配合物。因此 ,可采用P2 0 4通过非平衡溶剂萃取将Co(Ⅱ )以Co(Ⅲ )的形式与Ni(Ⅱ )或Cu(Ⅱ )分离 ,Co(Ⅲ )、Ni(Ⅱ )的分离系数为 378,Co(Ⅲ )、Cu(Ⅱ )的分离系数达到 90 8。     

二安替比林基－（2－溴）苯基甲烷与钒（Ⅴ）的显色反应研究

合成并鉴定了二安替比林基─（２─溴）苯基甲烷（ＤＡＯＢＭ）,研究了它与钒（Ⅴ）的显色条件。在Ｔｗｅｅｎ─８０和Ｍｎ（Ⅱ）存在下,ＤＡＯＢＭ与Ｖ（Ⅴ）在Ｈ３ＰＯ４（１＋１０）介质中生成橙色产物,λｍａｘ＝４９０ｎｍ,ε＝１．５５×１０６Ｌ·ｍｏｌ－１·ｃｍ－１,Ｖ（Ⅴ）的浓度在０．１～０．９μｇ／２５ｍｌ范围内符合比尔定律。方法用于中草药和矿样中钒的测定,结果满意。     

仲钨酸铵晶体生长速率常数和活化能研究

采用“成核期积分平均速率法”,运用阿累尼乌斯实验定律,求出仲钨酸铵晶体生长的表观活化能E表=94.657kJ/mol,得出仲钨酸铵晶体生长速率常数与温度的关系式为kn=8.46×1014exp(-94657/RT)。研究结果表明,温度升高,APT成核速率的增长幅度大于晶体生长速率的增长幅度,结晶产品粒度变细。