Dissolution kinetics of Amazonian metakaolin in hydrochloric acid

Clay Minerals ◽  
2017 ◽  
Vol 52 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Paula E.A. Lima ◽  
Rômulo S. Angélica ◽  
Roberto F. Neves
Keyword(s):  
Hydrochloric Acid ◽  
Dissolution Kinetics ◽  
Regression Coefficients ◽  
Shrinking Core Model ◽  
First Order ◽  
Constant Size ◽  
Shrinking Core ◽  
Kinetics Of Dissolution ◽  
Leaching Reaction ◽  
Kinetics Of

AbstractThe kinetics of dissolution of Amazonian metakaolin in hydrochloric acid (HCl) was studied using the ‘Shrinking Core Model’ for spherical and ‘flat plate’ particles of constant size. The Amazonian kaolin was calcined at 700°C for 2 h. The calcined samples (metakaolins) were leached in an HCl solution with 5% excess at 70, 80 and 95 ± 3°C for 3 h. Samples were collected every 15 min and subjected to Al analysis by the EDTA titrimetric method. Experimental data showed that the spherical morphology produced a better fit with respect to the regression coefficients. The activation energy of the reaction was 90.6 kJ/mol. The chemical process is a first-order leaching reaction. The results of the present study are consistent with those from previous research on this topic, which used HCl with an excess of >90%.

scholarly journals Dissolution kinetics of Amazonian metakaolin in nitric acid

Cerâmica ◽  
2018 ◽  
Vol 64 (369) ◽  
pp. 86-90 ◽  
Author(s):  
P. E. A. Lima ◽  
R. S. Angélica ◽  
R. F. Neves
Keyword(s):  
Nitric Acid ◽  
Flat Plate ◽  
Acid Leaching ◽  
Dissolution Kinetics ◽  
Regression Coefficients ◽  
First Order ◽  
Constant Size ◽  
Shrinking Core ◽  
Leaching Reaction ◽  
Kinetics Of

Abstract The kinetic study of Amazon metakaolin dissolution was performed with the application of the shrinking core model for spherical and ‘flat plate’ particles with constant size. The Amazon kaolin was calcinated at 700 ºC in order to produce metakaolin. This metakaolin was leached with 5% excess nitric acid at 70, 80 and 95±3 ºC for 3 h. Samples were collected every 15 min and subjected to aluminum analysis. The acid leaching was a chemically controlled process. The spherical morphology showed better fit than the flat plate particles when taking into account the regression coefficients. 91.58 kJ/mol of activation energy was found as well as an aluminum leaching reaction of the first order. The results found in this work using 5% excess acid and Amazon kaolin were consistent with previous research results using excess acid above 50% and standard kaolin.

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.

scholarly journals Acidic leaching of iron from Kaoje Goethite ore by hydrochloric acid: Kinetics modelling

2020 ◽  
Vol 39 (3) ◽  
pp. 800-806
Author(s):  
K.I. Ayinla ◽  
A.A. Baba ◽  
S. Girigisu ◽  
O.S. Bamigboye ◽  
B.C. Tripathy ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Acid Leaching ◽  
Dissolution Kinetics ◽  
Second Phase ◽  
Low Grade ◽  
Iron And Steel ◽  
Kinetics Modelling ◽  
Shrinking Core ◽  
Hcl Concentration ◽  
Kinetics Of

Considering the recent focus of the Nigeria Government to grow and develop the nation’s economy through the solid minerals sector reform, this study has been devoted to the kinetics of a Nigerian goethite ore by hydrochloric acid leaching for improved iron and steel industries applications. This study was performed in three different phases. In the first phase, acidic leaching of iron from a goethite ore was examined and the influence of the operating variables including: HCl concentration, leaching temperature, stirring speed and particle sizes was examined experimentally. The optimum condition was found to be HCl concentration of 1.81M, temperature of 80°C, 200 rpm stirring speed and particle size 0.09 μm for iron in the range of investigated parameters. Under those conditions, the highest iron recovery was obtained to be 95.67 %. In the second phase, the dissolution kinetics of iron was evaluated by the shrinking core models. The finding reveals that diffusion through the fluid was the leaching kinetics rate controlling step of the iron. The activation energy (Ea) was found to be 14.54 kJmol-1 for iron. Equation representing the leaching kinetic of iron was achieved to be 1−2/3α - (1 − x)2/3 = 0.7272 × e−38.29/8.314×T × t. The final stage of the experiment was carried out by characterizing the leached residues by X-ray diffractometer (XRD) and scanning electron microscopy (SEM), the result showed majorly the presence of rutile (TiO2), anglesite (PbSO4), and traces of iron-silicate face like pyrite (FeS), quartz (SiO2). Keywords: kinetics modelling, leaching, low-grade, recovery, shrinking core

Reaction Kinetics of In Situ Methanolysis of Jatropha curcas Seeds

2014 ◽  
Vol 625 ◽  
pp. 306-310 ◽  
Author(s):  
Nunung Prabaningrum ◽  
Lukman B. Ismail ◽  
Duvvuri Subbarao
Keyword(s):  
Jatropha Curcas ◽  
Reaction Rate ◽  
Order Reaction ◽  
First Order Reaction ◽  
Shrinking Core Model ◽  
Arrhenius Activation Energy ◽  
First Order ◽  
Shrinking Core ◽  
Kinetics Of

In-situ methanolysis of Jatropha curcas had been investigated at various reaction temperatures along with reaction time. Increasing reaction temperature enhanced the yield of biodiesel and shortened the reaction completion. According to shrinking core model, the mechanism of in-situ methanolysis of Jatropha curcas was chemical reaction control with the first-order reaction. The constant of the first-order reaction rate in the range of 5.15×10-9 to 8.78×10-9 m·s-1 and Arrhenius activation energy of 22.66 kJ⋅mol-1 were obtained.

scholarly journals Macerals of Shengli Lignite in Inner Mongolia of China and Their Combustion Reactivity

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Ying Yue Teng ◽  
Yu Zhe Liu ◽  
Quan Sheng Liu ◽  
Chang Qing Li
Keyword(s):  
Activation Energy ◽  
Homogeneous Model ◽  
Optical Microscope ◽  
Core Model ◽  
Shrinking Core Model ◽  
Compact Structure ◽  
Shrinking Core ◽  
Combustion Reactivity ◽  
Combustion Processes ◽  
Kinetics Of

The macerals, including fusinitic coal containing 72.20% inertinite and xyloid coal containing 91.43% huminite, were separated from Shengli lignite using an optical microscope, and their combustion reactivity was examined by thermogravimetric analysis. Several combustion parameters, including ignition and burnout indices, were analyzed, and the combustion kinetics of the samples were calculated by regression. Fusinitic coal presented a porous structure, while xyloid coal presented a compact structure. The specific surface area of fusinitic coal was 2.5 times larger than that of xyloid coal, and the light-off temperature of the former was higher than that of the latter. However, the overall combustion reactivity of fusinitic coal was better than that of xyloid coal. The combustion processes of fusinitic and xyloid coals can be accurately described by both the homogeneous model and the shrinking core model. The features of xyloid coal agree with the shrinking core model when its conversion rate is 10%–90%. The activation energy of fusinitic coal during combustion can be divided into three phases, with the middle phase featuring the highest energy. The activation energy of xyloid coal is lower than that of fusinitic coal in the light-off phase, which may explain the low light-off temperature of this coal.

scholarly journals Sustainable Hydrometallurgical Recovery of Valuable Elements from Spent Nickel–Metal Hydride HEV Batteries

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1062 ◽  
Author(s):  
Kivanc Korkmaz ◽  
Mahmood Alemrajabi ◽  
Åke Rasmuson ◽  
Kerstin Forsberg
Keyword(s):  
Sulfuric Acid ◽  
Hydrochloric Acid ◽  
Hybrid Electric Vehicle ◽  
Active Material ◽  
Sulfuric Acid Concentration ◽  
Dissolution Kinetics ◽  
Leach Solution ◽  
Nickel Metal ◽  
Acid Leach ◽  
Kinetics Of

In the present study, the recovery of valuable metals from a Panasonic Prismatic Module 6.5 Ah NiMH 7.2 V plastic casing hybrid electric vehicle (HEV) battery has been investigated, processing the anode and cathode electrodes separately. The study focuses on the recovery of the most valuable compounds, i.e., nickel, cobalt and rare earth elements (REE). Most of the REE (La, Ce, Nd, Pr and Y) were found in the anode active material (33% by mass), whereas only a small amount of Y was found in the cathode material. The electrodes were leached in sulfuric acid and in hydrochloric acid, respectively, under different conditions. The results indicated that the dissolution kinetics of nickel could be slow as a result of slow dissolution kinetics of nickel oxide. At leaching in sulfuric acid, light rare earths were found to reprecipitate increasingly with increasing temperature and sulfuric acid concentration. Following the leaching, the separation of REE from the sulfuric acid leach liquor by precipitation as NaREE (SO4)2·H2O and from the hydrochloric acid leach solution as REE2(C2O4)3·xH2O were investigated. By adding sodium ions, the REE could be precipitated as NaREE (SO4)2·H2O with little loss of Co and Ni. By using a stoichiometric oxalic acid excess of 300%, the REE could be precipitated as oxalates while avoiding nickel and cobalt co-precipitation. By using nanofiltration it was possible to recover hydrochloric acid after leaching the anode material.

Sign in / Sign up

Export Citation Format

Share Document