scholarly journals Dissolution Kinetics of Ilmenite Ore in A Binary Solution

2019 ◽  
Vol 4 (7) ◽  
pp. 51-57
Author(s):  
Chukwunonso Chukwuzuloke Okoye ◽  
Okechukwu Dominic Onukwuli ◽  
Chinenye Faith Okey-Onyesolu
Keyword(s):  
Particle Size ◽  
Acid Concentration ◽  
Reaction Temperature ◽  
Binary Solution ◽  
Product Layer ◽  
Solution Temperature ◽  
X Ray ◽  
Solid Ratio ◽  
Oxidant Concentration ◽  
Kinetics Of

Leaching of iron from ilmenite ore using a binary solution (HCl-NaNO3) was investigated. The raw ilmenite ore sample was characterized using Scanning Electron Microscopy (SEM), X-ray diffraction spectroscopy (XRD) and X-ray Flourescence (XRF) techniques. The influence of acid concentration, oxidant concentration, particle size, solution temperature, stirring speed and liquid-to-solid ratios on the extent of dissolution was examined. The experimental data obtained at various process parameter conditions were tested in six kinetics models: shrinking core model’s diffusion through liquid film model(DTLF), diffusion through product layer model (DTPL), surface chemical reaction model (SCR)); mixed kinetics model (MKM), Jander (three dimensional) model and Kröger and Ziegler model. The crystalline morphology of the sample was displayed by the SEM micrograph. XRF result revealed the dominance of titanium and iron in ilmenite while XRD confirmed that ilmenite exist mainly as FeTiO2. The results of the leaching studies showed that ilmenite dissolution in the binary solution increases with increasing acid concentration, oxidant concentration, reaction temperature, stirring speed and liquid-to-solid ratio; while it decreases with particle size. The study showed that 94.77% iron was dissolved by 1MHCl-0.6M NaNO3 at 75μm particle size, 75˚C reaction temperature, 300rpm stirring speed and 30L/g liquid-to-solid ratio. The kinetics of the leaching process was best described by Kröger and Ziegler model with diffusion through the product layer as rate controlling step. The activation energy, Ea, was calculated to be 6.42kJ/mol. The results indicate that HCl-NaNO3 binary solution can be used as an effective lixiviant for extracting iron from ilmenite ores.

The Dissolution Kinetics of Tincal in Phosphoric Acid Solutions

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Yuksel Abali ◽  
Salih U Bayca ◽  
Ayse E Guler
Keyword(s):  
Particle Size ◽  
Phosphoric Acid ◽  
Dissolution Rate ◽  
Acid Concentration ◽  
Reaction Temperature ◽  
Dissolution Kinetics ◽  
Reaction Model ◽  
Acid Solutions ◽  
Liquid Ratio ◽  
Kinetics Of

In this study, the dissolution kinetics of tincal in phosphoric acid solutions was investigated. The effects of reaction temperature, acid concentration, solid to liquid ratio, particle size and stirring speed were determined in the experiments. The results showed that the dissolution rate increased with increasing acid concentration, reaction temperature, stirring speed and increased with decreasing particle size and solid to liquid ratio. The dissolution rate was found to be based on the first order pseudo homogenous reaction model. The activation energy of the tincal in phosphoric acid solution was determined as 42.28 kJ.mol-1.

Kinetics of Sulfuric Acid Leaching of Boron Slurry

2011 ◽  
Vol 366 ◽  
pp. 370-373
Author(s):  
Feng Gao ◽  
Xiang Guang Xu ◽  
Lei Li ◽  
Huai Yu Sun ◽  
Hong Xin Wang
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Acid Concentration ◽  
Reaction Temperature ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Product Layer ◽  
Leaching Kinetics ◽  
Diffusion Controlled ◽  
Reaction Activation Energy

The results of a leaching kinetics study of boron slurry with sulfuric acid were presented. Effect of ore particle size, reaction temperature, and acid concentration on magnesium dissolution rate were determined. The results shown that leaching of about 64.61% of magnesium was achieved using (-200+ 250) mesh ore particle size at a reaction temperature of 60°C for reaction time 100 min with 25% sulfuric acid concentration. Leaching kinetics indicated that diffusion through the product layer was the rate controlling process during the reaction. The reaction activation energy was determined to be about 3.35 kcal/mol, which was characteristic for a diffusion– controlled process.

scholarly journals An Analytical Model Approach for the Dissolution Kinetics of Magnesite Ore Using Ascorbic Acid as Leaching Agent

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Nadeem Raza ◽  
Zafar Iqbal Zafar ◽  
Najam-ul-Haq
Keyword(s):  
Particle Size ◽  
Ascorbic Acid ◽  
Acid Concentration ◽  
Kinetic Data ◽  
Dissolution Kinetics ◽  
Reaction Parameters ◽  
Solid Ratio ◽  
Leaching Process ◽  
Kinetics Of ◽  
Model Approach

Ascorbic acid was used as leaching agent to investigate the dissolution kinetics of natural magnesite ore. The effects of various reaction parameters such as acid concentration, liquid-solid ratio, particle size, stirring speed, and temperature were determined on dissolution kinetics of the magnesite ore. It was found that the dissolution rate increased with increase in acid concentration, liquid-solid ratio, stirring speed, and temperature and decrease in the particle size of the ore. The graphical and statistical methods were applied to analyze the kinetic data, and it was evaluated that the leaching process was controlled by the chemical reaction, that is, . The activation energy of the leaching process was found to be 57.244 kJ mol−1 over the reaction temperature range from 313 to 343 K.

Experimental Study on Concentrating Scandium by Leaching from Associated Scandium Ore

2013 ◽  
Vol 734-737 ◽  
pp. 1033-1036
Author(s):  
Gui Fang Zhang ◽  
Peng Yan ◽  
Qing Rong Yang
Keyword(s):  
Experimental Study ◽  
Particle Size ◽  
Hydrochloric Acid ◽  
Acid Concentration ◽  
Hydrochloric Acid Concentration ◽  
Leaching Rate ◽  
Optimal Conditions ◽  
Research Results ◽  
Solid Ratio ◽  
Leaching Residue

Based on the benefication of the complex silicate ore containing scandium, the research about aid-leaching agent used in the leaching of the scandium concentrate was been conducted. And the suitable leaching agent and aid-leaching agent which the useful ions entered into leaching liquid and the harmful ions were kept in leaching residue were been found according to the experiment results. For the scandium of sample existed various complex silicate ore as isomorphism form, the research has adopted hydrochloric acid with aid-leaching agent to dissociate the silicate ore and make scandium entering into solution. The research results has shown that the scandium leaching rate could reach 92.06% under the optimal conditions which the hydrochloric acid concentration is 22.8%, the dosage of aid leaching agent is 6%, liquid solid ratio is 4:1, particle size of leaching material totally is less than 0.15mm and leaching time is 8h.

Leaching kinetics of copper and valuable metal extraction from copper-cadmium residues of zinc hydrometallurgy by oxidation acid leaching

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jihao Guo ◽  
Hongao Xu ◽  
Bo Li ◽  
Yonggang Wei ◽  
Hua Wang
Keyword(s):  
Hydrogen Peroxide ◽  
Acid Concentration ◽  
Acid Leaching ◽  
Metal Extraction ◽  
Agitation Rate ◽  
Leaching Kinetics ◽  
Solid Ratio ◽  
Zinc Hydrometallurgy ◽  
Kinetics Of ◽  
Leaching Efficiency

Abstract Multiple purification of zinc sulfate solution is an important process for zinc hydrometallurgy, and large quantities of copper-cadmium residues are generated as byproducts in this process. Copper-cadmium residues contain a large number of valuable metals that must be recovered. A comprehensive extraction process has been proposed using sulfuric acid as the leaching reagent and hydrogen peroxide as the oxidizing reagent. The effects of acid concentration, leaching temperature, leaching time, liquid-to-solid ratio, hydrogen peroxide dosage and stirring speed on the leaching efficiency were investigated. The optimum conditions were determined as an acid concentration of 150 g/L, liquid-to-solid ratio of 4:1, hydrogen peroxide amount of 20 mL, time of 60 min, temperature of 30 °C, particle size of −d75 μm, and agitation rate of 300 r/min. It was concluded that the leaching efficiency of copper and cadmium reached 97%, but because of the existence of zinc sulfide in the residues, a lower leaching efficiency of zinc was obtained. Furthermore, the leaching kinetics of copper was also studied based on the shrinking core model. The activation energy for copper leaching was 5.06 kJ/mol, and the leaching process was controlled by the diffusion through the product layer.

Oxidation of Nickel(II) and Manganese(II) by Peroxodisulfate in Aqueous Solution in the Presence of Molybdate. Crystal Structure of the (NH4)6[NiMo9O32].6H2O Product

1992 ◽  
Vol 45 (12) ◽  
pp. 1943 ◽  
Author(s):  
SJ Dunne ◽  
RC Burns ◽  
GA Lawrance
Keyword(s):  
Rate Constant ◽  
Linear Dependence ◽  
Ph Dependence ◽  
Order Rate Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Oxidant Concentration ◽  
Ph Range ◽  
Kinetics Of

Oxidation of Ni2+,aq, by S2O82- to nickel(IV) in the presence of molybdate ion, as in the analogous manganese system, involves the formation of the soluble heteropolymolybdate anion [MMogO32]2- (M = Ni, Mn ). The nickel(IV) product crystallized as (NH4)6 [NiMogO32].6H2O from the reaction mixture in the rhombohedra1 space group R3, a 15.922(1), c 12.406(1) � ; the structure was determined by X-ray diffraction methods, and refined to a residual of 0.025 for 1741 independent 'observed' reflections. The kinetics of the oxidation were examined at 80 C over the pH range 3.0-5.2; a linear dependence on [S2O82-] and a non-linear dependence on l/[H+] were observed. The influence of variation of the Ni/Mo ratio between 1:10 and 1:25 on the observed rate constant was very small at pH 4.5, a result supporting the view that the precursor exists as the known [NiMo6O24H6]4- or a close analogue in solution. The pH dependence of the observed rate constant at a fixed oxidant concentration (0.025 mol dm-3) fits dequately to the expression kobs = kH [H+]/(Ka+[H+]) where kH = 0.0013 dm3 mol-1 s-1 and Ka = 4-0x10-5. The first-order dependence on peroxodisulfate subsequently yields a second-order rate constant of 0.042 dm3 mol-1 s-1. Under analogous conditions, oxidation of manganese(II) occurs eightfold more slowly than oxidation of nickel(II), whereas oxidation of manganese(II) by peroxomonosulfuric acid is 16-fold faster than oxidation by peroxodisulfate under similar conditions.

Crystallization of nanosized titania particles prepared by the sol-gel process

1994 ◽  
Vol 9 (8) ◽  
pp. 2102-2108 ◽  
Author(s):  
E. Haro-Poniatowski ◽  
R. Rodríguez-Talavera ◽  
Heredia M. de la Cruz ◽  
O. Cano-Corona ◽  
R. Arroyo-Murillo
Keyword(s):  
Particle Size ◽  
Steady State ◽  
Light Scattering ◽  
Sol Gel ◽  
X Ray ◽  
Constant Size ◽  
Size Profile ◽  
Nanosized Titania ◽  
Sol Gel Process ◽  
Kinetics Of

Sols of titania were obtained by the sol-gel method and their size profile was followed by dynamical light scattering. In the early stages of the reaction an unstable behavior was detected. After this unstable regime the particle size reaches a steady state where the sols have a constant size while increasing in number. Once the sol concentration reaches its overlap value, the gelation regime takes place. For samples prepared in this way Raman spectra and x-ray diffractometry were used to characterize the kinetics of crystallization of the material.

Extraction of Tin (Sn) from Solder Dross by Using Hydrochloric Acid Leaching Treatment

2015 ◽  
Vol 754-755 ◽  
pp. 567-570
Author(s):  
Syarifah Aminah Ismail ◽  
Noorina Hidayu Jamil ◽  
Kamarudin Hussin ◽  
Mohd Arif Anuar Mohd Salleh
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Hydrochloric Acid ◽  
Acid Concentration ◽  
Acid Leaching ◽  
Experimental Results ◽  
Solution Temperature ◽  
Hydrochloric Acid Leaching ◽  
Stirring Time ◽  
Acid Aqueous Solution

This project deals with the experimental results of leaching of Sn from solder dross by means of leaching using different concentration of hydrochloric acid (HCl). Solder dross was sieved to obtain a mean particle size of 75 μm. The solder dross powder obtained was leached by using HCl acid aqueous solution. To optimize the parameter required for recovery of Sn from solder dross, initially the bench scale studies were carried out using varying acid concentration, stirring time and temperature. The experimental indicate that 98.7% of Sn was leached out from solder dross using 0.1M of HCl, 24 hours of stirring time at60°C solution temperature.

Kinetic study and modeling of the solid-state reaction Y2BaCuO5 + 3BaCuO2 + 2CuO ⇉ 2YBa2Cu3O6.5−x + xO2

1990 ◽  
Vol 5 (10) ◽  
pp. 2056-2065 ◽  
Author(s):  
Nae-Lih Wu ◽  
Ta-Chin Wei ◽  
Shau-Y Hou ◽  
S-Yen Wong
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Solid State Reaction ◽  
Size Dependence ◽  
Average Particle Size ◽  
Average Particle ◽  
Fractional Conversion ◽  
X Ray ◽  
Unreacted Core ◽  
Kinetics Of

The kinetics of the solid-state reaction Y2BaCuO5 + 3BaCuO2 + 2CuO ⇉ 2YBa2Cu3O6.5−x + xO2 was studied by using x-ray diffractometric and thermogravimetric analyses. Both analyses established that the reaction was well described by the kinetic equation: 1 − 3(1 − F)2/3 + 2(1 − F) = k0 exp(− E/RT)t, where F is the fractional conversion of a calcined powder, E is 520 kcal/molc and, for a rcactant mixture with an average particle size of 3 μm, k0 is 2.03 ⊠ 1092 min−1. An unreacted-core shrinking model was proposed to obtain the particle-size dependence of the reaction, and predicted that the pre-exponential constant k0 changed with reactant particle size by k0 = 2.03 ⊠ 1092(3/d)2 exp(4/d − 4/3), where d is the average reactant particle size in μm.

scholarly journals Crystallization kinetics of K2O·TiO2·3GeO2 glass studied by DTA

2008 ◽  
Vol 40 (3) ◽  
pp. 333-338 ◽  
Author(s):  
S. Grujic ◽  
N. Blagojevic ◽  
M. Tosic ◽  
V. Zivanovic ◽  
J. Nikolic
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Particle Size ◽  
Differential Thermal Analysis ◽  
Crystallization Kinetics ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Samples ◽  
Kinetics Of

Crystallization kinetics of K2O?TiO2?3GeO2 glass was investigated by differential thermal analysis (DTA). Experiments were performed on powder samples with a particle size < 0.037 mm. The glass samples were heated at different rates in the temperature range 20-750?C. The kinetic parameters, activation energy for the crystallization process, Ec and Avrami exponent, n were calculated. Powder X-ray diffraction analysis (XRD) of crystallized glass reveals the presence of crystalline K2O?TiO2?3GeO2 indicating polymorphic crystallization with interface controlled crystal growth.

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