Determination of the kinetics of dissolution of materials in liquid metals

1968 ◽  
Vol 2 (5) ◽  
pp. 411-413 ◽  
Author(s):  
V. N. Eremenko ◽  
Ya. V. Natanzon
Keyword(s):  
Liquid Metals ◽  
Kinetics Of Dissolution ◽  
Kinetics Of

scholarly journals The investigation of the kinetics of hydrochemical oxidation of metal sulphides with the aim of determination of the optimal conditions for the selective extraction of molybdenum from ores

2005 ◽  
Vol 41 (1) ◽  
pp. 33-45 ◽  
Author(s):  
V. Lutsik ◽  
A. Sobolev
Keyword(s):  
Rotation Frequency ◽  
Rotating Disk ◽  
Selective Extraction ◽  
Solution Temperature ◽  
Specific Rate ◽  
Disk Rotation ◽  
Diffusion Controlled ◽  
Kinetics Of Dissolution ◽  
Kinetics Of

The kinetics of the oxidation of molybdenyte, pyrite and sphalerite in solutions of nitric acid, hydrogen peroxide, and sodium hypochlorite was studied by the rotating disk method. The influence of the molar concentration of reagent, pH of solution, temperature, disk rotation frequency, and duration of measurements on the specific rate of hydrochemical oxidation of sulpfides was determined. The kinetic models allowing to calculate the dissolution rate of sulphides when these parameters change simultaneously were obtained. The conditions of kinetically and diffusion-controlled processes were detected. The details of mechanism of the studied processes were revealed. The nature of intermediate solid products, the reasons and the conditions of their formation as well as the character of their influence on the kinetics of dissolution processes were determined. The probable schemes of interactions corresponding to the observable kinetic dependences were offered. The conditions of the effective and selective molybdenum leaching directly from ore without its concentration were found.

scholarly journals Influence of the textural and structural functions of the Urals carnallite rocks on the kinetics of dissolution processes

2021 ◽  
pp. 62-67
Author(s):  
Т.Р. Шакиров ◽  
М.С. Вафина
Keyword(s):  
Chemical Composition ◽  
Structural Features ◽  
Dissolution Process ◽  
Insoluble Residue ◽  
The Urals ◽  
Slowing Down ◽  
Rate Of Dissolution ◽  
Kinetics Of Dissolution ◽  
Kinetics Of

В статье показана необходимость исследования кинетики процессов растворения карналлитовых пород Приуралья. Описана методика подготовки образцов и лабораторного изучения скорости растворения. Представлены данные о химическом составе образцов 4-х цветовых разностей карналлитовых пород, текстурно-структурных особенностей, результатов по определению скорости растворения и вещественного состава нерастворимого в воде остатка. Цель исследования заключалась в изучении скорости и процессов растворения в воде при температуре 500С в режиме вынужденной конвекции и оценке влияния текстурно-структурных особенностей карналлитовых пород. Задачами исследования являлись: определение солевого и минерального составов, изучениеструктуры и микровключений в шлифах, проведение экспериментов по кинетикерастворения. При решении поставленных задач использовались следующие методы: АЭС-спектрометрия, петрографический анализ, гидростатический метод, РКФА. Проанализирован фактический материал исследования, сделаны соответствующие выводы. Проведенными исследованиями было показано, что важными факторами, влияющими на кинетику процессов растворения, являются вещественный состав и текстурно-структурные свойства. В работе определена суммарная (массовая) скорость растворения образцов. Железооксидная пленка, оконтуривающая зерна карналлитовых пород, экранирует поверхность растворения, замедляя процесс диффузии. Наличие галита и неравномерное его содержание вызывает колебания скорости растворения изамедляет процесс растворения во времени. Микровключения газов положительно влияют на динамику процесса растворения, усиливая конвекцию и массоперенос. С увеличением гидродинамических параметров растворителя (плотности и вязкости) скорость растворения понижается. Установленные закономерности могут оказывать существенное влияние на процессы, происходящие при скважинной добыче (подземное растворение) и галургической переработке карналлитовых руд. The article shows the need to study the kinetics of the dissolution processes of carnallite rocks of the Permian deposits of the Urals. The technique of preparation of samples, laboratory study of the rate of dissolution in water is described. The data on the chemical composition of samples of 4-color differences of carnallite rocks, textural and structural features, the results of determining the rate of dissolution and the material composition of the water-insoluble residue are presented. The purpose of the study was to study the rate and processes of dissolution in water at a temperature of 500C in the forced convection mode and to assess the influence of the textural and structural features of the carnallite rocks of the Urals. The objectives of the study were: determination of salt and mineral compositions, study of textural and structural features and assessment of the effect of microinclusions on the kinetics of the dissolution process. When solving the tasks, the following methods were used: study of the textural and structural features of carnallite rocks - by the petrographic method; determination of the rate of dissolution and density of samples - by the gravimetric method; determination of the density of brines - pycnometric method; the chemical composition of the initial samples and solutions (brines) was analyzed by AES-spectrometry; the mineral composition of the water-insoluble residue - by X-ray quantitative phase analysis. The factual material of the research is analyzed, the corresponding conclusions are drawn. Studies have shown that important factors affecting the kinetics of dissolution processes are the material composition and textural-structural properties. In this work, the total (mass) rate of dissolution of samples was determined, including the vertical and horizontal components. The iron oxide film outlining the grains of carnallite rocks screens the dissolution surface, slowing down the diffusion process. The presence of halite and its uneven content causes fluctuations during dissolution, slowing down the dissolution process over time. Microinclusions of gases have a positive effect on the dynamics of the dissolution process, enhancing convection and mass transfer. With an increase in the hydrodynamic parameters of the solvent (density and viscosity), the dissolution rate decreases. The research results can be suitable for the organization of mining by underground dissolution and for the processing of carnallite rocks of the Permian deposits of the Urals by the halurgical method.

Determination of microbiological activity during the processing of frost damaged sugar beets

2014 ◽  
pp. 228-231 ◽  
Author(s):  
Maciej Wojtczak ◽  
Aneta Antczak-Chrobot ◽  
Edyta Chmal-Fudali ◽  
Agnieszka Papiewska
Keyword(s):  
Sugar Beet ◽  
Microbiological Activity ◽  
Microbiological Contamination ◽  
Sugar Beets ◽  
Bacterial Metabolites ◽  
Kinetics Of

The aim of the study is to evaluate the kinetics of the synthesis of dextran and other bacterial metabolites as markers of microbiological contamination of sugar beet.

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus
Keyword(s):  
Structural Changes ◽  
Oxidation Processes ◽  
High Oleic ◽  
Painting Materials ◽  
Insulating Paper ◽  
Different Types ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Natural Ester

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

Interphase distribution of 2-furylethylenes

1985 ◽  
Vol 50 (8) ◽  
pp. 1642-1647 ◽  
Author(s):  
Štefan Baláž ◽  
Anton Kuchár ◽  
Ernest Šturdík ◽  
Michal Rosenberg ◽  
Ladislav Štibrányi ◽  
...  
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Transport Rate ◽  
Phase System ◽  
Two Phase ◽  
Interphase Distribution ◽  
Distribution Kinetics ◽  
System 1 ◽  
Kinetics Of

The distribution kinetics of 35 2-furylethylene derivatives in two-phase system 1-octanol-water was investigated. The transport rate parameters in direction water-1-octanol (l1) and backwards (l2) are partition coefficient P = l1/l2 dependent according to equations l1 = logP - log(βP + 1) + const., l2 = -log(βP + 1) + const., const. = -5.600, β = 0.261. Importance of this finding for assesment of distribution of compounds under investigation in biosystems and also the suitability of the presented method for determination of partition coefficients are discussed.

Determination of the Nucleophilicity of Tricarbonyliron Coordinated Cyclohepta-1,3,5-triene

1999 ◽  
Vol 64 (11) ◽  
pp. 1770-1779 ◽  
Author(s):  
Herbert Mayr ◽  
Karl-Heinz Müller
Keyword(s):  
Gibbs Energy ◽  
Ambient Temperature ◽  
Rate Constants ◽  
Second Order ◽  
Order Rate ◽  
Electrophilic Additions ◽  
Kinetics Of

The kinetics of the electrophilic additions of four diarylcarbenium ions (4a-4d) to tricarbonyl(η4-cyclohepta-1,3,5-triene)iron (1) have been studied photometrically. The second-order rate constants match the linear Gibbs energy relationship log k20 °C = s(E + N) and yield the nucleophilicity parameter N(1) = 3.69. It is concluded that electrophiles with E ≥ -9 will react with complex 1 at ambient temperature.

scholarly journals Recognition of hydrogen isotopomers by an open-cage fullerene

2013 ◽  
Vol 371 (1998) ◽  
pp. 20110629 ◽  
Author(s):  
Yasujiro Murata ◽  
Shih-Ching Chuang ◽  
Fumiyuki Tanabe ◽  
Michihisa Murata ◽  
Koichi Komatsu
Keyword(s):  
Equilibrium Constants ◽  
Equilibrium Mixture ◽  
Size Difference ◽  
Binding Affinities ◽  
Kinetic Isotope ◽  
Molecular Sizes ◽  
Lower Temperature ◽  
Kinetics Of ◽  
Pressure Hydrogen

We present our study on the recognition of hydrogen isotopes by an open-cage fullerene through determination of binding affinity of isotopes H 2 /HD/D 2 with the open-cage fullerene and comparison of their relative molecular sizes through kinetic-isotope-release experiments. We took advantage of isotope H 2 /D 2 exchange that generated an equilibrium mixture of H 2 /HD/D 2 in a stainless steel autoclave to conduct high-pressure hydrogen insertion into an open-cage fullerene. The equilibrium constants of three isotopes with the open-cage fullerene were determined at various pressures and temperatures. Our results show a higher equilibrium constant for HD into open-cage fullerene than the other two isotopomers, which is consistent with its dipolar nature. D 2 molecule generally binds stronger than H 2 because of its heavier mass; however, the affinity for H 2 becomes larger than D 2 at lower temperature, when size effect becomes dominant. We further investigated the kinetics of H 2 /HD/D 2 release from open-cage fullerene, proving their relative escaping rates. D 2 was found to be the smallest and H 2 the largest molecule. This notion has not only supported the observed inversion of relative binding affinities between H 2 and D 2 , but also demonstrated that comparison of size difference of single molecules through non-convalent kinetic-isotope effect was applicable.

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