Kinetics
Browse 60 curated documents about kinetics in The Archive — the 2RA-Edition digital library for engineering and scientific research. This collection of books, journal articles, theses, reports, and technical documents on kinetics spans extractive metallurgy, mining engineering, chemistry, and applied science. Every document is searchable in full text; sign in to read, download, ask AI questions about any document, or generate cited research drafts with the AI Researcher.
Kinetics of Ion Exchange in Magnesium Sulfate Leaching of Rare Earths and Aluminum from Ionic Rare Earth Ores
Mingbing Hu, Yajian Shao
Magnesium sulfate leaching of ionic rare earth ores is generally characterized by a smooth outflow curve, a long leaching time, and a high impurity content in the leach liquor. To reveal the leaching law of rare earth cations and impurity aluminum ions in the leaching process of ionic rare earth ores in magnesium sulfate, equilibrium leaching and leaching kinetics experiments were carried out usin
2022 Xu Willemite leaching kinetics in dilute sulfuric acid
Hongsheng Xu, Yanan Qian
The present study was undertaken to investigate the effects of temperature, sulfuric acid concentration, agitation speed, and particle size on the high-temperature leaching kinetics of artificial willemite in low sulfuric acid solution. A mathematical model taking into account the change in acid concentration was evaluated for the leaching rate increased with increasing sulfuric acid concentration
Leaching Kinetics of Sulfides from Refractory Gold Concentrates by Nitric Acid
Denis A. Rogozhnikov, Andrei A. Shoppert
The processing of refractory gold-containing concentrates by hydrometallurgical methods is becoming increasingly important due to the depletion of rich and easily extracted mineral resources, as well as the need to reduce harmful emissions from metallurgy, especially given the high content of arsenic in the ores. This paper describes the investigation of the kinetics of HNO₃ leaching of sulfide go
2020 Karimov Arsenic sulfide leaching kinetics in copper sulfate
Kirill A. Karimov, Denis A. Rogozhnikov
The overall decrease in the quality of mineral raw materials, combined with the use of arsenic-containing ores, results in large amounts of various intermediate products containing this highly toxic element. The use of hydrometallurgical technologies for these materials is complicated by the formation of multicomponent solutions and the difficulty of separating copper from arsenic. Previously, for t
2017 Zhao Hemimorphite leaching kinetics in ammonium chloride
Duoqiang Zhao, Shenghai Yang
The leaching kinetics of hemimorphite (Zn4Si2O7(OH)2·H2O) in ammonium chloride solution was presented in detail. Effects of stirring speed (150–350 rpm), leaching temperature (75–108 °C), particle size of hemimorphite (45–150 µm), and the concentration of ammonium chloride (3.5–5.5 mol/L) on the zinc extraction rate were studied. The zinc extraction rate enhanced slightly with the increase in stir
Leaching Kinetics of Zinc from Metal Oxide Varistors (MOVs) with Sulfuric Acid
Youngjin Kim, Jaeryeong Lee
The leaching kinetics of zinc from zinc oxide-based metal oxide varistors (MOVs) was investigated in H2SO4 at atmospheric pressure. Kinetics experiments were carried out at various agitation speeds, particle sizes, initial H2SO4 concentrations, and reaction temperatures. It was determined that the leaching rate of zinc was independent of agitation speed above 300 rpm and also independent of partic
Kinetics of Chalcopyrite Leaching by Hydrogen Peroxide in Sulfuric Acid
Miroslav Soki´ c, Branislav Markovi´ c
In ores, chalcopyrite is usually associated with other sulfide minerals, such as sphalerite, galena, and pyrite, in a dispersed form, with complex mineralogical structures. Concentrates obtained by flotation of such ores are unsuitable for pyrometallurgical processing owing to their poor quality and low metal recovery. This paper presents the leaching of chalcopyrite concentrate from the location
Effect of Preliminary Alkali Desilication on Ammonia Pressure Leaching of Low-Grade Copper–Silver Concentrate
Kirill Karimov, Andrei Shoppert
Ammonia leaching is a promising method for processing low-grade copper ores, especially those containing large amounts of oxidized copper. In this paper, we study the effect of Si-containing minerals on the kinetics of Cu and Ag leaching from low-grade copper concentrates. The results of experiments on the pressure leaching of the initial copper concentrate in an ammonium/ammonium-carbonate soluti
Predicting Cyanide Consumption in Gold Leaching: A Kinetic and Thermodynamic Modeling Approach
Yaser Kianinia, Mohammad Reza Khalesi
The consumption of cyanide during processing operations is a major economic cost in the extraction of gold from its ores, while the discharge of cyanide wastes may result in significant environmental pollution. Many factors influence the levels of consumption and discharge of cyanide, including ore mineralogy and lixiviant solution chemistry. This paper proposes a robust methodology to estimate le
Chalcopyrite Leaching in Alkaline Monosodium Glutamate Solutions: Process Optimization and Kinetic Study
Carlos G. Perea Solano, Christian F. Ihle
This study investigated the kinetics of chalcopyrite dissolution in an alkaline monosodium glutamate (MSG) solution using H2O2 and KMnO4. The aims were to optimize process conditions for maximum copper dissolution and to study the kinetic mechanism of dissolution under varying conditions, such as particle size, oxidant type and concentration, temperature, and the presence of gangue minerals. Resul
INVESTIGATION INTO THE LEACHING KINETICS AND MECHANISM OF NICKEL EXTRACTION FROM ASBESTOS TAILINGS VIA NITRIC ACID TREATMENT
Omirserik Baigenzhenov, Assel Dagubayeva
This study presents the results of an investigation into the kinetics of nitric acid leaching of nickel from the magnetic fraction of chrysotile asbestos beneficiation waste. The relevance of this work stems from the necessity to involve large-tonnage technogenic formations into processing circuits. It was established that the application of magnetic separation enables preliminary concentration of
Phthalic acid-assisted rare earth leaching process from ionic rare earth ore: leaching behavior, kinetics, and complexation mechanism
Xiang Hong, Zhenyue Zhang
The extraction of rare earth (RE) elements from ion-adsorption type RE ores relies on in-situ leaching technology. However, the leaching process faces technical challenges such as low leaching efficiency and limited recovery rates. In this study, MgSO4 was used as the leaching agent, with phthalic acid (PA) introduced as a complexation-assisted additive to improve RE leaching efficiency. The addit
Enhanced biosorptive recovery of Mn2+ from low-grade ore leachate using naoh activated mangifera indica kernel biomass kinetics isotherms and desorption studies
Soumyashree Parida, Lala Behari Sukla
The study investigates the enhanced biosorptive recovery of manganese ions (Mn2+) from low-grade ore leachate using NaOH activated Mangifera indica kernel biomass. The objective is to optimize the recovery process through kinetic, isotherm, and desorption studies. The methodology involves the preparation of the biomass and subsequent batch experiments to evaluate the biosorption capacity under var
Lithium Recovery from a Clay-Type Ore by Pressure Leaching Oxidation: A Kinetic Study
Guadalupe Lizeth Leyva-Soriano, Jesús Leobardo Valenzuela-García
The increasing demand for lithium in energy storage technologies has renewed interest in clay-type deposits as alternative resources to brines and hard rock ores. This study investigates the leaching behavior of a Mexican clay-type lithium ore through conventional, hot, and pressure leaching using sulfuric acid. Mineralogical characterization (XRD and SEM–EDS) revealed that montmorillonite (~56 wt
Determination of the mass transfer rate constant in a laboratory column flotation using the bubble active surface coefficient
Amir Eskanlou, Mohammad Reza Khalesi
This study aimed to introduce a new approach to determine the mass transfer rate constant in a laboratory column flotation through an analogy to a mass transfer process. The RTD of the column at two separate bubble sizes were modeled using both conventional N-mixer and N-mixer with back-mixing flow models. The number of perfect mixers (N) and the corresponding backflow coefficients (λ) were optimi
Fluidized bed roasting of cocoa nibs speeds up processing and favors the formation of pyrazines
Ruth Fabiola Pe ˜na-Correa, Burçe Ataç Mogol
Roasting is an important step in cocoa processing causing water loss and generating volatile compounds responsible for chocolate aroma like nitrogen-heterocycles. In this study, the comparison of two techniques, oven roasting and fluidized bed roasting, in terms of effective water diffusivity (De) and activation energies of formation (Ea) of nitrogen-heterocycles was achieved with cocoa nibs. Flui
Roasting kinetics of high-arsenic copper concentrates: a review
I. Wilkomirsky, R. Parra
The roasting process of copper concentrates containing variable quantities of arsenic in a fluidized bed regime was analyzed, considering the technical literature published on the topic in the last quarter century. Although emphasis has been given to the analysis in the fluidized bed regime, other processes have also been considered, under a reducing, neutral or oxidizing atmosphere. The kinetic m
Study on the Reaction System of Copper and Iron Sulfides during Roasting
E Brocchi, P Jena
Sulfi de concentrates are essential raw materials in metallic copper production, as their roasting processes yield various products, such as copper sulphate and iron oxides. This study aimed to investigate the thermodynamics and kinetics of the roasting reaction system involving copper and iron sulfides, providing insights into necessary conditions for selectively obtaining specific compounds. Usin
A KINETICS STUDY OF COFFEE BEAN OF ROASTING AND STORAGE CONDITIONS
SHU-YAO TSAI, BING-FANG HWANG
Coffee beans roasting is an important step in coffee production because it enables the development of flavor, aroma and color. Most coffee beans are commercially roasted in large-scale, but some coffee drinkers prefer to precisely control the freshness and the special flavor by their own roasting method. This study was conducted to develop a novel approach to thermal decomposition that includes th
KINETICS OF MASS LOSS OF ARABICA COFFEE DURING ROASTING PROCESS
GUILLERMO A. VARGAS-ELÍAS, PAULO C. CORRÊA
Roasting is one of the most complex coffee processing steps due to simultaneous transfers of heat and mass. During this process, beans lose mass because of fast physical and chemical changes that will set color and flavor of the commercial coffee beverage. Therefore, we aimed at assessing the kinetics of mass loss in commercially roasted coffee beans according to heating throughout the processing.
Influence of different temperatures and airflows on drying of natural and pulped coffee
Guilherme E. Alves, Flávio M. Borém
This study aimed to evaluate drying kinetics for natural and pulped coffee, using different temperatures and drying airflows. For the conduction of the experiment, coffee fruits (Coffea arabica L. cv. Topázio) were harvested manually, selecting only ripe fruits and subsequent to the hydraulic separation. For drying the coffee, use a mechanical dryer with two temperatures (40 and 45°C) and four dry
The leaching of chalcopyrite with ferric sulfate and ferric chloride
D. L. Jones, E. Peters
The leaching of natural chalcopyrite was investigated using ferric sulfate and ferric chloride solutions, highlighting the different chemical reactions involved. Notably, ferric chloride was identified as a more efficient leaching reagent, with a substantially increased leaching rate linked to finer particle sizes and higher iron concentrations. Unlike ferric sulfate, which preferentially leached
Thermal analysis and kinetics of the cha
A. Mitovski, N. Štrbac
The paper presents the results of experimental investigation of the chalcopyrite-pyrite concentrate oxidation in air. This study aimed to better understand the thermodynamic characteristics, kinetic parameters, and reaction mechanisms involved during the oxidation of polymetallic chalcopyrite-pyrite concentrates. The methodology included characterization of the initial sample and oxidation product
Kinetics of iron copper sulphides oxidat
Emilien Burger, David Bourgarit
This article deals with one specific step of the copper extractive metallurgy process: the roasting of iron–copper sulphides. It aims at shedding light on an archaeological issue: the reconstruction of the copper extractive metallurgy processes during protohistory (IVe–IIe millennium BC). Experimental simulations are performed at laboratory scale by modeling the conditions of protohistoric furnace
A Study on the Combined Flotation–Roasting–Leaching Process for Treating High-Carbon Gold Ore and Its Kinetics
Yongcheng Zhou, Wenping Chen
Direct cyanide leaching of high-carbon gold ores typically results in poor gold extraction due to the “preg-robbing” effect of carbonaceous matter. This study investigates a refractory high-carbon gold ore from Laos. Based on detailed process mineralogy that identified the occurrence state of gold and the distribution of harmful impurities, a combined process consisting of flotation pre-concentrat
2017 Wang Manganese leaching from semi oxidized ores with sucrose
Yuhong Wang, Shenglong Jin
The extraction of manganese from a semi-oxidized manganese ore was investigated with sucrose as the reducing agent in dilute sulfuric acid medium. The kinetics of leaching manganese from the complex ore containing MnCO3 and MnO2 was also investigated. The effects of sucrose and sulfuric acid concentrations, leaching temperature and reaction time on the total Mn (TMn), MnO2 and MnCO3 leaching were
2005 Jae Min Yoo Kinetics of the Volatilization Removal of Lead in Electric Arc Furnace Dust matertrans.46.323
Jae-Min Yoo, Byung-Su Kim
The selective removal of lead and chlorine from electric arc furnace (EAF) dust is critical for recovering high purity zinc through high temperature metal recovery (HTMR) processes. This study investigates the volatilization reaction of lead in EAF dust across temperatures ranging from 973 to 1223 K in air. The primary volatilization reaction was established, demonstrating that with a reaction tim
Application of Mixed Potential Theory to Leaching of Mineral Phases
César A. C. Sequeira
Leaching is a central unit operation in the hydrometallurgical processing of minerals, which often occurs by means of electrochemical reactions. The objective of this study is to apply mixed potential theory to elucidate the kinetics involved in oxidative and reductive leaching processes. The methodology involves an examination of electron-conducting phases such as native metals, selected oxides,
Kinetics and Mechanisms of Chalcopyrite Dissolutionat Controlled Redox Potential of 750 mV in Sulfuric Acid Solution
Yubiao Li, Zhenlun Wei
To better understand chalcopyrite leach mechanisms and kinetics, for improved Cu extraction during hydrometallurgical processing, chalcopyrite leaching has been conducted at solution redox potential 750 mV, 35–75 ˝C, and pH 1.0 with and without aqueous iron addition, and pH 1.5 and 2.0 without aqueous iron addition. The activation energy (Ea) values derived indicate chalcopyrite dissolution is ini
Direct Acid Leaching of Sphalerite: An Approach Comparative and Kinetics Analysis
Nallely G. Picazo-Rodríguez, Ma. de Jesus Soria-Aguilar
The present work reports the direct leaching of zinc from a sphalerite concentrate in acid media. Lab-scale and pilot-scale experiments were conducted in atmospheric-pressure and low-pressure reactors, respectively. Leaching of zinc and precipitation of iron was achieved in the same stage using different reagents like Fe3+, O2, O3, and Fe2+ (which is continuously oxidized in the leaching solution
Hydrometallurgical Process and Kinetics of Leaching Manganese from Semi-Oxidized Manganese Ores with Sucrose
Yuhong Wang, Shenglong Jin
The extraction of manganese from a semi-oxidized manganese ore was investigated with sucrose as the reducing agent in dilute sulfuric acid medium. The kinetics of leaching manganese from the complex ore containing MnCO3 and MnO2 was also investigated. The effects of sucrose and sulfuric acid concentrations, leaching temperature and reaction time on the total Mn (TMn), MnO2 and MnCO3 leaching were
Thermodynamics and Kinetics of Sulfuric Acid Leaching Transformation of Rare Earth Fluoride Molten Salt Electrolysis Slag
Lijie Chen, Jiacong Xu
In the realm of rare earth element recovery through molten salt electrolysis, the loss of approximately 8% in waste molten salt slag poses significant challenges. Despite the pressing need for effective recycling technologies for rare earth molten salt slag, scant research has addressed this concern, necessitating a novel approach for its treatment. This study investigates the recovery of rare ear
Electrochemical degradation of 1 2 dichl
Rajesh Bejankiwar, Jerald A. Lalman
The electrochemical degradation of 1,2-dichloroethane (DCA) was examined in a synthetic groundwater medium. An undivided electrolytic reactor constructed with 304L-type stainless-steel plate electrodes was employed in all experiments. The removal of total organic carbon (TOC) content during the electrolysis of DCA was experimentally examined. Stainless-steel plate electrodes were effective in degr
THE KINETICS OF NICKEL ELECTRODEPOSITION INHIBITION BY ADSORBED HYDROGEN AND ANIONS
E. CHASSAING, M. JOUSSELLIN
This study investigates the kinetics of nickel electrocrystallization through impedance measurements in strongly acidified chloride electrolytes and with additives such as 2 butyne 1,4 diol and sodium benzenesulfonate. In chloride solutions at pH 0.5, notable inductive effects and a distinct capacitive low-frequency feature were observed, contrasting with less acidified environments. The presence
Aims and methods in non-isothermal reaction kinetics
G. Várhegyi
The majority of the works dealing with non-isothermal kinetics assumes only one kinetic differential equation, uses linearization techniques and do not check the fit between the simulated and the experimental data. It is not clear from the literature why we need kinetic evaluations at all in this field. Due to this controversial situation, the author has outlined his views on the aims and methods
Thermodynamics, Kinetics and Equilibrium Analysis of Sulphur dioxide Oxidation in a Catalytic Reactor
Wordu, A. A, Briggs, M. I. F
The research presents sulphur dioxide oxidation from elemental oxygen for a typical study of thermodynamics equilibrium constant of reversible reaction kinetics in a reactor system. A fundamental stoichiometric balanced chemical equation model on the species taking part in the sulphur dioxide SO2 oxidation reaction is applied for the study. Equilibrium compositions of the species involved in the r
THE USE OF THE RISING TEMPERATURE TECHNIQUE TO ESTABLISH KINE’I-IC PARAMETERS FOR SOLID-STATE DECOMPOSITIONS A VACUUM MICROBALANCE
D. DOLLIMORE, G. R HEAL
This study investigates the applicability of the rising temperature technique for establishing kinetic parameters in solid-state decompositions using vacuum microbalance methods. The primary objective is to address key experimental aspects affecting the apparent weight of substances under rising temperature conditions. Through a comprehensive theoretical treatment combining kinetic laws, including
SATL MODEL LESSON IN CHEMICAL KINETICS
Misbah Nazir, Iftikhar Imam Naqvi
Studies in order to pursue kinetics and mechanism of chemical reactions are a vital component of chemical literature. SATL literature is still not available for promoting this vital aspect of chemistry teaching. A lesson pertaining to this important issue has been developed and various parameters of kinetic studies are explained therein.
2-Kinetics: Rates of Chemical Reactions
Judd Christian F. Bañas
This experiment investigates the rate of the chemical reaction involving the decomposition of sodium thiosulfate (Na2S2O3) and hydrochloric acid (HCl) to form colloidal sulfur particles (S), sulfur dioxide (SO2), water (H2O), and sodium chloride (NaCl). The objective was to explore the rate constant (k) as a function of temperature and the reaction rate's dependence on reactant concentration over
New experimental data and kinetic rate expression for the Claus reaction
W. D. Monnery, W. Y. Svrcek
The modified Claus process is the most common method for the conversion to sulphur of the hydrogen sulphide contained in sour oil and natural gas. This study focuses on the relatively unexamined reaction kinetics of the front-end reaction furnace in the Claus process, where sulphur production occurs and hydrocarbon contaminants are destroyed. Specifically, the kinetics of the reaction between H₂S
New experimental data and kinetic rate expression for the Claus reaction
W. D. Monnery, W. Y. Svrcek
The modified Claus process is the most common method for the conversion to sulphur of the hydrogen sulphide contained in sour oil and natural gas. An important but relatively unstudied part of the Claus process is the reaction kinetics of the front-end furnace where sulphur production occurs. This work studies the reaction between H₂S and SO₂ at actual Claus plant reaction temperatures and residen
KINETICS OF THE SODIUM BICARBONATE-SULFUR DIOXIDE REACTION
TIM C. KEENER, SOON-JAI KHANG
A parallel reaction path model has been developed to explain the reaction between sodium bicarbonate (NaHCO3) particles and sulfur dioxide (SO2) gas. This reaction is atypical compared to other alkali and alkaline compounds with SO2 in that the optimum reaction temperature occurs where thermal decomposition of the parent particles is pronounced. The model accounts for the concomitant thermal decom
Kinetic Study of Naphthalene Sulfonation Reaction
Salwa Hawash, Nahed Kamal
This study represents a mathematical procedure for the kinetic analysis of naphthalene sulfonation using sulfuric acid at molar ratios ranging from 0.7 to 1.5 and reaction temperatures from 115 to 180 °C. The overall sulfonation comprises many consecutive, parallel, and reversible reactions. Representative samples of the reaction mixture are analyzed by high-performance liquid chromatography for q
Chemical reaction kinetics in practice
Rob. J. Berger, E. Hugh Stitt
This paper discusses the significant role of chemical reaction kinetics in the design and operation of chemical reactors, which are essential components in various chemical processes. The objective is to present a comprehensive overview of reaction kinetics, focusing on its practical applications in industrial settings. The methodology includes an analysis of data acquired through an extensive que
COS-Forming Reaction between CO and Sulfur: A High-Temperature Intrinsic Kinetics Study
Kunal Karan, Anil K. Mehrotra
Carbonyl sulfide (COS) is formed in the front end of Claus plants, which are used to recover sulfur from acid gases. This study aims to fill the knowledge gap regarding the kinetics of the reaction between carbon monoxide (CO) and sulfur for COS formation. An experimental investigation was conducted to measure the intrinsic kinetics of this homogeneous gas-phase reaction across a temperature range
Comprehensive Method Based on Model Free Method and IKP Method for Evaluating Kinetic Parameters of Solid State Reactions
Yunqing Han, Tianxiang Li
This study presents a comprehensive method for evaluating kinetic parameters of solid state reactions, addressing the limitations of existing methods. The objective is to provide a rigorous approach that incorporates the impact of heating programs on the activation energy, thereby enhancing the reliability of extracted kinetic parameters. A theoretical review of the isoconversional principle of mo
Aqueous Oxidation of Sulfur(IV) Catalyzed by Manganese(II): A Generalized Simple Kinetic Model
BOŠTJAN PODKRAJŠEK, GORAZD BERČIČ
The reaction kinetics of S(IV) autoxidation catalyzed by Mn(II) in the pH range 3–5 typical for atmospheric liquid water was investigated. For reactions with pH maintained constant during the reaction course, the predictions obtained by a simple integral approach cover kinetic results only for concentrations of HSO3− up to 0.2 mM at pH 4.5. Thus, a generalized simple kinetic model, which can be us
AN APPROACH TO SOLID STATE KINETICS
LARS CARLSEN, ANDERS FELDTHUS
An approach to kinetic evaluation of pyrolytic reactions of solid material is discussed based on the assumption that the overall reaction can be described by n th-order kinetics, n possibly being fractional. The applicability of the n th-order kinetic approach to solid state reactions is illustrated by studies on the pyrolysis of polystyrene and coals. The possible applications to ‘single-componen
THERMODYNAMIC AND KINETICS ANALYSIS OF THE SULFUR-FIXED ROASTING OF ANTIMONY SULFIDE USING ZnOAS SULFUR-FIXING AGENT
Z. Ouyanga, Y.F. Chena
Currently, the commercial antimony metallurgy is mainly based on pyrometallurgical processes and oxidative volatilization of Sb2S3 is an essential step. This step includes the problems of high energy consumption and low concentration of SO2 pollution. Aiming at these problems, we present a new method of sulfur-fixing roasting of antimony sulfide. This method uses ZnO as a sulfur-fixing agent, and
Chromium electrodeposits for improving performance characteristics of engineering tools and components
Protsenko, V.S., Danilov, F.I.
Chromium electrodeposition plays a crucial role in modern surface engineering, particularly for enhancing the performance of engineering tools and components. With growing environmental concerns regarding hexavalent chromium, which is known to be toxic, there is an urgent need for alternative electroplating methods. This study aims to investigate the kinetics and mechanisms involved in the electro
Kinetics and mechanism of chromium electrodeposition from formate and oxalate solutions of Cr(III) compounds
V. Protsenko, F. Danilov
Kinetics of multistep reaction of Cr(III) ions discharge to metal was studied on a stationary electrode and on a rotating disk electrode from the solutions containing formic acid or oxalic acid. The electroreduction of Cr(III) complex ions in aqueous solutions is shown to proceed via the formation of relatively stable intermediates—Cr(II) compounds which are partially removed into bulk solution. T
Investigation of chrome( VI) oxide production from chromite concentrate by alkali fusion
Ciineyt Arslan, Gijkhan Orhan
The possibility of producing chrome(VI) oxide from domestic chromite concentrates was investigated by carrying out laboratory-scale alkali fusion and water leaching experiments. The effects of temperature, the amount of NaOH added, and the flow rate of air on chromium extraction efficiency in an alkali fusion step were examined. Fusion product was leached with water to produce a clean Na2CrO4 solu
Removal of lead from aqueous solutions b
R. Kamaraj, P. Ganesan
The present study provides an electrocoagulation process for the removal of lead from water using magnesium and galvanized iron as anode and cathode, respectively. The various operating parameters such as the effect of initial pH, current density, electrode configuration, inter-electrode distance, co-existing ions and temperature on the removal efficiency of lead were studied. The results showed t
Exploring Kinetics of Phenol Biodegradation by Cupriavidus taiwanesis 187
Yu-Hong Wei, Wei-Chuan Chen
Phenol biodegradation in batch systems using Cupriavidus taiwanesis 187 has been experimentally studied. To determine the various parameters of a kinetic model, combinations of rearranged equations have been evaluated using inverse polynomial techniques for parameter estimation. The correlations between lag phase and phase concentration suggest that considering phenol inhibition in kinetic analysi
Adsorption behaviour of copper and gold Glycinates in alkaline media onto activated carbon. Part 2: Kinetics
P.J. Tauetsile, E.A. Oraby
The kinetics for the competitive adsorption of gold and copper onto activated carbon from synthetic alkaline glycine solutions was studied. The adsorption rate for both gold and copper at the initial stage was modelled using the Fleming k,n adsorption kinetic model. The coefficient of variation (R 2) of the model were close to unity for both gold and copper adsorption data. The effects of pH, free gl
THE FUNDAMENTAL KINETIC CHARACTERISTICS OF AQUEOUS DISSOLUTION OF CHLORIDE AND FLUORIDE SALTS FROM SECONDARY ALUMINIUM DROSS
István Illés, Meriem Sassi
The salt content in the secondary dross obtained alongside recovered aluminium through the hot processing of primary melting dross poses challenges for further material utilization. This study focuses on leaching secondary dross samples, derived from industrial processes of aluminium alloy scrap melting, with water at room temperature while varying the Liquid/Solid (L:S) ratios. Key insights were
The cracking shrinking model for solid-fluid reactions
J.P. Martins, F. Margarido
A model based on the shrinking principle is developed to describe the non-catalytic solid-fluid reactions when particles crack during the process. Analytical and numerical solutions of the governing equations under isothermal conditions are presented for some reaction orders, valid for all geometries considered. Experimental results of refining of Fe-Si alloys by acid leaching are suggested as an
The cementation of copper and cadmium by zinc powder
Associação Brasileira de Metalurgia, Materiais e Mineração
The cementation of copper and cadmium by zinc powder was investigated in order to assess the influence of different parameters in the process. The results showed that the process follows a first order reaction with two stages in both systems. In the system Cu/Zn, the second stage is faster than the first while in the system Cd/Zn the second stage is slower than the first. In the system Cu/Zn, the
Kinetic mechanisms of cementation of cadmium ions by zinc powder from sulphate solutions
S.R. Younesi, H. Alimadadi
The cementation of cadmium ions by zinc powder was studied in a batch reactor at low and high concentrations at pH 5.2–5.4. The results indicate that the reaction is first-order, and XRD and SEM analysis confirmed that the deposited layer is metallic without evidence of basic zinc sulphate or cadmium re-dissolution. The dependence of the reaction constant on initial cadmium concentration validates
Kinetic Aspects of Gold and Silver Recovery in Cementation with Zinc Power and Electrocoagulation Iron Process
Gabriela V. Figueroa Martinez, José R. Parga Torres
The Merrill-Crowe or Cementation process is employed for the concentration and purification of gold and silver extracted from cyanide solutions. This study investigates the kinetic aspects of traditional cementation and a novel electrocoagulation (EC) technique for recovering precious metals from cyanide solutions. Initially, the fundamentals of both processes are introduced, followed by a compreh