硫化镍加压氧化酸浸动力学的研究

湿法冶金中,硫酸常压氧化浸取高冰镍时,形成硫化镍(Nis)而存留在浸取渣中,只有在高温下加压浸取,才能使 Nis浸溶。因此研究 Nis 加压氧化酸浸动力学,颇有现实意义。样品制备和实验方法实验所用 Nis 试样系由单质镍和硫在真空下加热化合而成。经 X 光粉晶分析,其晶型为 r—Nis,与高冰镍常压浸取渣中的硫化镍形态一致。合成 r-Nis 熔     

LIQUID AXIAL BACKMIXING IN MULTISTAGE BUBBLE COLUMN

The characteristics of a staged bubble column can be described by a multi-stage backmixing model,provided: (1) Each stage can be considered as a perfect mixing reactor,and (2) The backmixing coeffi-cients do not vary with time and reactant concentrations.Experimental results indicate that the first conditionis approached under certain conditions,while the second assumption is correct.Studies were made using steady state chemical tracer method to determine the backmixing coefficientsof each plate between stages.The fluid flow through the holes of perforatcd plates is a stochastic process.From the statistical point,the experimental data could be correlated by semicmpirical equation developed.This equation can also be used to correlate the data reported by Nishiwaki for bubble column with plateshaving high percentage of opening area and large size holes between stages.Continuous oxidation of unsaturated sulfur compounds (mainly in the form of thiosulfatc and also somein polythionate form) in nickel ammonium carbonate solution were carried out in bubble columns with heightof 3400mm and diameters of 36 mm and 100mm respectively.The oxidation has to be taken in a multistagebubble column for high degree of oxidation.The axial concentration of unsaturated sulfur compoundsalong a multi-stage bubble column can be calculated from the backmixing model and the kinetic equationof oxidation.Results of calculation agree with the data taken along the column height.Equation was alsodeveloped to calculate the optimum temperatures of oxidation which agree favorably with the experimentalresults.     

相转移催化元素硫歧化反应的动力学

在45—70℃、氢氧离子浓度为0.02—0.14mol/l范围内研究了四氯乙烯/水体系中氢氧化四丁铵相转移催化元素硫歧化反应初始阶段的动力学.实验得到表观速度表达式:R_(?)a=k~(?)[Q~+]_(aq)[OH~-]_(aq)[S]_(org)~(1/2),并导得表观活化能为79kJ/mol.用液液体系伴有快速化学反应的传质模型成功地解释了本体系动力学.推测了元素硫的歧化反应机理,从动力学上提出了本体系相转移催化的证据.     

用反向胶团制备稳定ZrO2超细粉的研究

以注入法研究了金属离子及氨水在ＡＯＴ－ｉｓｏｏｃｔａｎｅ－ｗａｎｔｅｒ反胶团中的溶解性，用光散射技术测定了胶团的大小，用冷冻蚀刻复形技术表征了反胶团的微观结构；研究了以反胶团为基础溶液多种制备方式对粉末的影响，实验制备了Ｙ２Ｏ３及ＣｅＯ２稳定的四方相ＺｒＯ２超细粉，研究表明，将金属离子包溶于反胶团是制备良好颗粒的必要条件。     

液滴在自由沉降时的质量传递

对运动液滴的质量传递方程进行变量分离,获得了双变量的刘维尔方程.应用变分法和瑞利—里兹方法求出双变量刘维尔方程的特征值及特征函数.运动液滴质量传递方程的解是对应于不同特征值的特解的迭加F=1-2/πsum from n=1 to k(1)B_nexp(-λ_n~2τ)(?)Z_n(x,y)dxdyNewman的刚性球模型和Kronig-Brink的内环流模型是本工作所发展的模型的两个极端情况,上述方程计算结果与水-正丁醇-丁二酸的实验结果是互相吻合的.     

氧化铜与二氧化硫及氧作用生成硫酸铜的动力学

在不同温度及气相组成下,曾对氧化铜与SO_2及O_2作用生成硫酸铜的动力学进行了研究。 反应先生成盐基性硫酸铜,然后再生成硫酸铜。俟硫酸铜生成量达30％后,形成一硬壳,此时反应为气体通过硬壳层的扩散所控制。 当反应仅生成盐基性硫酸铜时,盐基性硫酸铜生成的百分数f_b=a+b_t;t为时间,a及b为常数。生成硫酸铜时,硫酸铜的最初生成百分数f_c=kt。俟硬壳形成后,反应即减慢。 在硬壳未形成之前,生成盐基性硫酸铜及硫酸铜的速度均可用下式表示: R_(av)=(k_1·PSO_2)/(1+k_2·(PO_2)~(1/2)+k_3·PSO_2) 式中R_(av)为时间平均反应速度,PSO_2及PO_2分别为SO_2及O_2的分压,k_1、k_2及k_3为常数。实验结果推论出反应为表面上氧离子上吸附的SO_2进一步作用为SO_4~(-2)的速度所控制。当气相中没有氧存在时,反应结果尚生成氧化亚铜。由于氧化亚铜系p-型半导体,因此反应较有氧气存在时为快。当气相中有SO_3存在时,反应速度较仅有SO_2及O_2存在时为快。在此种情况下,反应机理估计与目前结论完全不同。     

滴流床中流体分布的研究现状及展望

回顾了滴流床流体分布研究的历史和技术进步,分析了测量液体分布大尺度和小尺度均匀性的方法,讨论了改善流体分布均匀性的措施,指出了滴流床操作特性的非线性与小尺度不均匀性的关系,最后对值得深入的工作提出了建议。     

从甘草中提取甘草酸不同提取方法的比较

对几种不同的从甘草中提取甘草酸的提取方法进行了实验比较. 结果表明, 微波辅助提取法与热回流法、索氏(Soxhlet)提取法、室温提取法等传统方法相比,具有提取高效、快速、完全及节省时间、溶剂和能耗等优点, 是一种适于从甘草中快速提取甘草酸的新方法.     

液滴凝并端效应对单液滴传质测定的影响及消除

For the mass transfer to single drops during the stage of steady buoyancy-driven motion, experimental measurement is complicated with the terminal effect of additional mass transfer during drop formation and coalescence at the drop collector. Analysis reveals that consistent operating conditions and experimental procedure are of critical significance for minimizing the terminal effect of drop coalescence on the accuracy of mass transfer The novel design of a totally-closed extraction column is proposed for this purpose, which guarantees that the volumetric rate of drop phase injection is exactly equal to that of withdrawal of drops. Tests in two extraction systems demonstrate that the experimental repeatability is improved greatly and the terminal effect of mass transfer during drop coalescence is brought well under control.     

湿法冶金科学研究三十年

建国三十年来,我国湿法冶金科学技术获得了很大发展,无论在科学研究和生产应用方面均取得了很大成绩。本文拟就有色金属湿法冶金科学研究的进展作一简介。一、工艺过程开发为了多快好省地开发有色金属矿藏资源