Dissolution kinetics of cerussite in an alternative leaching reagent for lead

2015 ◽  
Vol 69 (3) ◽  
Author(s):  
Qi-Cheng Feng ◽  
Shu-Ming Wen ◽  
Yi-Jie Wang ◽  
Qin-Bo Cao ◽  
Wen-Juan Zhao
Keyword(s):  
Dissolution Kinetics ◽  
Product Layer ◽  
Surface Chemical ◽  
Surface Chemical Reaction ◽  
Mixed Control ◽  
Shrinking Core ◽  
Two Stages ◽  
Kinetics Of ◽  
And Diffusion ◽  
Rate Controlling Step

AbstractThe dissolution kinetics of cerussite was investigated using methanesulphonic acid (MSA) as an alternative leaching reagent. The effects of particle size, stirring speed, acid concentration, and reaction temperature on the lead dissolution rate were determined. The dissolution process followed the kinetic law of the shrinking-core model, and a corresponding mixed control model was found suitable for representing the rate-controlling step. The mixed kinetic model comprised two stages: surface chemical reaction (283 K to 303 K) and diffusion through the product layer (303 K to 323 K). The activation energies of these sequential stages were 43.20 kJ mol

Leaching and Kinetic Modeling of Malaysian Low Grade Manganese Ore in Sulfuric Acids

2016 ◽  
Vol 1133 ◽  
pp. 629-633 ◽  
Author(s):  
Suhaina Ismail ◽  
Hashim Hussin ◽  
Syed Fuad Saiyid Hashim ◽  
Norazharuddin Shah Abdullah
Keyword(s):  
Dissolution Kinetics ◽  
Product Layer ◽  
Low Grade ◽  
Manganese Ore ◽  
Leaching Process ◽  
Mixed Control ◽  
New Variant ◽  
Experimental Parameters ◽  
Kinetics Of ◽  
And Diffusion

The leaching process of Malaysian low grade manganese ore (LGMO) using bamboo sawdust (BSD) as reducing agent in acidic medium (H2SO4) and the dissolution kinetics of this ore was investigated. Acid concentration, reaction temperature, and BSD loading were chosen as experimental parameters through application of response surface methodology (RSM). For analysis of the kinetic data in this study, the SCM with surface chemical reaction and diffusion through product layer, the mixed control modelled and also new variant SCM were evaluated. The reaction kinetics of this leaching process was determined, and it is observed that it fits the model of 1-23X-(1-X)23=kt with activation energy of 69.3kJ/mol. The reaction rate for LGMO leaching using BSD was found to be diffusion through product layer.

KINETIC MODEL FOR IDENTIFYING THE RATE CONTROLLING STEP OF THE ALUMINUM LEACHING FROM PEAT CLAY

2018 ◽  
Vol 80 (2) ◽  
Author(s):  
Agus Mirwan ◽  
Susianto Susianto ◽  
Ali Altway ◽  
Renanto Handogo
Keyword(s):  
Chemical Reaction ◽  
Product Layer ◽  
Rate Equations ◽  
Stage Model ◽  
Surface Chemical ◽  
Surface Chemical Reaction ◽  
Leaching Process ◽  
Shrinking Core ◽  
Solid Liquid ◽  
Rate Controlling Step

The aluminum (Al) leaching kinetics from peat clay was investigated using various acid concentrations 1 M to 6 M, particle sizes +70-120 mesh to +200-325 mesh and temperatures 30 °C to 90 °C. They all have significant effects on aluminum leaching process. The Al leaching recovery was best found to be 91.3 % at 4 M hydrochloric acid (HCl), using a particle size of +200-325 mesh with solid/liquid of 0.02 g·ml-1. Leaching kinetic study was applied to the two rate equations proposed that is acid diffusion via product layer and surface chemical reaction using the shrinking core (SC) model to analyze the leaching data. The product layer diffusion is controlling Al leaching process for one-stage model, while for two-stage model, it was controlled by surface chemical reaction. The activation energy in the two rate controlling step was 82.79 kJ mol-1 and 27.08 kJ mol-1, respectively. 

Kinetics of Atmospheric Acid Leaching of a Limonitic Laterite

2013 ◽  
Vol 319 ◽  
pp. 14-18
Author(s):  
Kui Liu ◽  
Xi Liu
Keyword(s):  
Atmospheric Pressure ◽  
Acid Leaching ◽  
Shrinking Core Model ◽  
Surface Chemical ◽  
Surface Chemical Reaction ◽  
Nickel Laterite ◽  
Shrinking Core ◽  
Semi Empirical ◽  
Kinetics Of ◽  
Rate Controlling Step

A limonitic nickel laterite was leached by sulfuric acid at atmospheric pressure. Kinetics of leaching within the temperature range of 75-100°C was studied. The leaching kinetics followed the shrinking core model. The diffusion through the liquid film could be negligible under the agitation speed of 600rpm or above. Surface chemical reaction was the rate-controlling step. The semi-empirical kinetic equation was determined and the activation energy was 52.843kJ/mol.

scholarly journals Application of the Shrinking-Core Models for Determination of Dissolution Kinetics of Mn and Zn from Spent Zinc–Carbon Battery Powder in Organic Acid Solution

2019 ◽  
Vol 27 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Tevfik Agacayak ◽  
Hasan Ali Taner
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Acetic Acid Solution ◽  
Dissolution Kinetics ◽  
Kinetic Studies ◽  
Product Layer ◽  
Different Temperatures ◽  
Shrinking Core ◽  
Kinetics Of Dissolution ◽  
Kinetics Of

Abstract In this study, dissolution kinetics of manganese and zinc from spent zinc–carbon batteries in acetic acid solution was investigated. To determine the kinetics of dissolution of manganese and zinc, shrinking core model was applied to dissolution recoveries obtained at different temperatures. As a result of kinetic studies, it was determined that manganese and zinc were dissolved in acetic acid solution by diffusion from product layer and then activation energies (Ea) were calculated.

Reaction kinetics of malachite in ammonium carbamate solution

2015 ◽  
Vol 69 (9) ◽  
Author(s):  
Ying-Bo Mao ◽  
Jiu-Shuai Deng ◽  
Shu-Ming Wen ◽  
Jian-Jun Fang
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Dissolution Rate ◽  
Batch Reactor ◽  
Shrinking Core Model ◽  
Surface Chemical ◽  
Surface Chemical Reaction ◽  
Ammonium Carbamate ◽  
Shrinking Core ◽  
Kinetics Of

AbstractThe dissolution of malachite particles in ammonium carbamate (AC) solutions was investigated in a batch reactor, using the parameters of temperature, AC concentration, particle size, and stirring speed. The shrinking core model was evaluated for the dissolution rate increased by decreasing particle size and increasing the temperature and AC concentration. No important effect was observed for variations in stirring speed. Dissolution curves were evaluated in order to test shrinking core models for fluid-solid systems. The dissolution rate was determined as being controlled by surface chemical reaction. The activation energy of the leaching process was determined as 46.04 kJ mol

Kinetics Study of the Digestion of Magnesium Chloride Dihydrate in a Molten Salt Electrolyte

2020 ◽  
Vol 865 ◽  
pp. 105-110
Author(s):  
Muhammad Tawalbeh
Keyword(s):  
Magnesium Chloride ◽  
Kinetics Study ◽  
Chloride Dihydrate ◽  
Chlorination Process ◽  
Second Stage ◽  
Shrinking Core ◽  
Two Stages ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Rate Controlling Step

During the electrolytic reduction of magnesium, it is very important to understand the mechanism of the digestion of the magnesium chloride dihydrate granules in the molten electrolyte throughout the chlorination process. This work aimed to investigate the kinetics of this digestion process. The results showed that the granules digestion is happening in two stages. The first stage is very fast, hence, results in the formation of MgOHCl during the dehydration and the hydrolysis of magnesium chloride dihydrate in the interior of the granules. The kinetic results for the first stage was best modeled using shrinking core model where the surface reaction was the rate controlling step. The second stage was best modeled as a first-order homogenous reaction. The kinetic parameters for the two stages were determined along with the Arrhenius plots. The results of this kinetics study are essential for the mathematical modeling of the chlorination process of the magnesium chloride dihydrate granules.

Leaching Kinetics and Seperation of Antimony and Arsenic from Arsenic Alkali Residue

2011 ◽  
Vol 402 ◽  
pp. 57-60 ◽  
Author(s):  
Gui Sheng Zeng ◽  
Hui Li ◽  
Su Hua Chen ◽  
Xin Man Tu ◽  
Wen Bin Wang
Keyword(s):  
Shrinking Core Model ◽  
Leaching Kinetics ◽  
Surface Chemical ◽  
Leaching Rate ◽  
Kinetics Equation ◽  
Surface Chemical Reaction ◽  
Liquid Ratio ◽  
Shrinking Core ◽  
Solid Liquid ◽  
Kinetics Of

The separation of antimony and arsenic and leaching kinetics of arsenic from arsenic alkali residue were investigated. The influencing factors such as solid/liquid ratio, stir speed, temperature and time on leaching of arsenic were studied. The results show that the leaching rate reaches 87.75% at the condition of solid/liquid ratio of 1:4 , stir speed of 600r/min ,temperature of 90°C and time of 60min. The leaching process was controlled by the surface chemical reaction and the kinetics of leaching arsenic followed the model of shrinking core. The activation energy was found to be 666.57kJ/mol. The kinetics equation was expressed as shrinking core model.

scholarly journals Fluoride Leaching of Titanium from Ti-Bearing Electric Furnace Slag in [NH4+]-[F−] Solution

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1176
Author(s):  
Fuqiang Zheng ◽  
Yufeng Guo ◽  
Feng Chen ◽  
Shuai Wang ◽  
Jinlai Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Electric Furnace ◽  
Kinetic Equations ◽  
Surface Chemical ◽  
Leaching Rate ◽  
Surface Chemical Reaction ◽  
Mechanism And Kinetics ◽  
Semi Empirical ◽  
Kinetics Of ◽  
Furnace Slag

The effects of F− concentration, leaching temperature, and time on the Ti leaching from Ti-bearing electric furnace slag (TEFS) by [NH4+]-[F−] solution leaching process was investigated to reveal the leaching mechanism and kinetics of titanium. The results indicated that the Ti leaching rate obviously increased with the increase of leaching temperature and F− concentration. The kinetic equation of Ti leaching was obtained, and the activation energy was 52.30 kJ/mol. The fitting results of kinetic equations and calculated values of activation energy both indicated that the leaching rate of TEFS was controlled by surface chemical reaction. The semi-empirical kinetics equation was consistent with the real experimental results, with a correlation coefficient (R2) of 0.996. The Ti leaching rate reached 92.83% after leaching at 90 °C for 20 min with F− concentration of 14 mol/L and [NH4+]/[F−] ratio of 0.4. The leaching rates of Si, Fe, V, Mn, and Cr were 94.03%, 7.24%, 5.36%, 4.54%, and 1.73%, respectively. The Ca, Mg, and Al elements were converted to (NH4)3AlF6 and CaMg2Al2F12 in the residue, which can transform into stable oxides and fluorides after pyro-hydrolyzing and calcinating.

Oxidation of Copper Sulfides in Aqueous Ammonia. III. Kinetic Characteristics

1979 ◽  
Vol 32 (12) ◽  
pp. 2597 ◽  
Author(s):  
AO Filmer ◽  
AJ Parker ◽  
BW Clare ◽  
LGB Wadley
Keyword(s):  
Aqueous Ammonia ◽  
Sulfide Oxidation ◽  
Metal Sulfide ◽  
Diffusion Control ◽  
Sulfate Ions ◽  
Kinetics Of Oxidation ◽  
Copper Sulfides ◽  
Shrinking Core ◽  
Kinetics Of ◽  
And Diffusion

The kinetics of oxidation with oxygen of chalcocite, Cu2S, to CuS in buffered aqueous ammonia at pH 10.5 at 30� can be modeled approximately by a shrinking core of Cu2S within a thickening shell of CuxS (x ≥ 1). The Cu2S core offers partial cathodic protection to the CuxS and diffusion of Cu+ through CuxS controls the rate of reaction. The kinetics of oxidation of covellite, CuS, to Cu2+, sulfur and sulfate ions in the same solvent can be modeled by a shrinking core of CuS surrounded by a shrinking sphere of CuyS (y < 1) which is much less effectively protected cathodically by the CuS core. Oxidation of CuS is subject to mixed chemical and diffusion control. Rates of oxidation of NiS and of CuS, in the presence and absence of tetrachloroethene and ammonium sulfate, show that, whether sulfur is a major oxidation product or not, the presence of sulfur has very little, if any, influence on the rate or mechanism of oxidation. This is contrary to current ideas on metal sulfide oxidation.

Nitridation Isothermal Kinetics of In Situ β-Sialon Bonded Al2O3-C Refractories

2016 ◽  
Vol 697 ◽  
pp. 572-575
Author(s):  
Xue Qing Yang ◽  
Nai Peng ◽  
Cheng Ji Deng
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Isothermal Kinetics ◽  
Nitridation Reaction ◽  
Result Show ◽  
Different Temperatures ◽  
Two Stages ◽  
Kinetics Of ◽  
And Diffusion

The kinetics of in-situ β- Sialon bonded Al2O3-C (SAC) refractories were investigated by TGA techniques via isothermal nitridation experiments at different temperatures. The result show that the nitridation process of in-situ β-Sialon bonded Al2O3-C refractories can be divided into two stages: the nitridation reaction rate controlling stage in the first 10 min, and the apparent activation energy of nitridation reaction is 370 kJ/mol ; then the reaction is controlled by both chemical reaction and diffusion rate in the following 110 min, the apparent activation energy of nitridation reaction is 410 kJ/mol.

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