Kinetic Study of the Leaching of Iraqi Akashat Phosphate Ore Using Lactic Acid

In the present work, a kinetic study was performed to the extraction of phosphate from Iraqi Akashat phosphate ore using organic acid. Leaching was studied using lactic acid for the separation of calcareous materials (mainly calcite). Reaction conditions were 2% by weight acid concentration and 5ml/gm of acid volume to ore weight ratio. Reaction time was taken in the range 2 to 30 minutes (step 2 minutes) to determine the reaction rate constant k based on the change in calcite concentration. To determine value of activation energy when reaction temperature is varied from 25 to 65 , another investigation was accomplished. Through the kinetic data, it was found that selective leaching was controlled by surface chemical reaction. The study showed that the reaction kinetics was specifically described by the shrinking core model (SCM). Regression analyses gave values of activation energy (Ea) and Arrhenius constant (ko) as 40.108 KJ/mole and (2.256 103 sec-1) respectively.

Download Full-text

Kinetic Model of the 1,2-Propanediol Oxidation Reaction in the Presence of 3wt%Pd/α-Al2O3 Catalyst

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.903.143 ◽

2021 ◽

Vol 903 ◽

pp. 143-148

Author(s):

Svetlana Cornaja ◽

Svetlana Zhizhkuna ◽

Jevgenija Vladiko

Keyword(s):

Activation Energy ◽

Lactic Acid ◽

Kinetic Model ◽

Catalytic Oxidation ◽

Molecular Oxygen ◽

Oxidation Reaction ◽

Main Product ◽

Oxidation Process ◽

Water Solution ◽

Reaction Conditions

Supported 3wt%Pd/α-Al₂O₃ catalyst was tested in selective oxidation of 1,2-propanediol by molecular oxygen. It was found that the catalyst is active in an alkaline water solution. Lactic acid was obtained as the main product of the reaction. Influence of different reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. Partial kinetic orders of the reaction with respect to 1,2-propanediol, c0(NaOH), p(O2), n(1,2-PDO)/n(Pd)) were determined and an experimental kinetic model of the catalytic oxidation reaction was obtained. Activation energy of the process was calculated and was found to be about 53 ± 5 kJ/mol.

Download Full-text

Research on Enrichment of P2O5 from Low-Grade Carbonaceous Phosphate Ore via Organic Acid Solution

Journal of Analytical Methods in Chemistry ◽

10.1155/2019/9859580 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7

Author(s):

Fei Xie ◽

Jie Zhang ◽

Jiyan Chen ◽

Jianrui Wang ◽

Lin Wu

Keyword(s):

Organic Acid ◽

Reaction Times ◽

Acid Leaching ◽

Gangue Mineral ◽

Low Grade ◽

Reaction Conditions ◽

Phosphate Ore ◽

Orthogonal Experiments ◽

Different Types ◽

Acid Acid

The theory of using dilute organic acid solutions to leach the carbonaceous part from low-grade carbonaceous phosphate ore has been proposed by researchers as an effective approach to increase the proportion of P and to utilize the abundant low-grade resource. In this paper, a comprehensive experimental study was carried out to confirm the feasibility of organic acid leaching and investigate the optimized leaching conditions. Utilizing the low-grade carbonaceous phosphate ore produced in Zhijin, southwest of China, the effects of different types of acid, acid concentrations, reaction temperatures, reaction times, and liquid-solid ratios on leaching rate of P2O5 were evaluated using single-factor experiments and orthogonal experiments. The reaction mechanism, examined by SEM technique and the reaction thermodynamic analysis suggested that the leaching of P2O5 mainly resulted from the process of dissolution of dolomite (the main gangue mineral) in organic acid, consequently enriching the phosphate rock (the mineral of value). The effectiveness and impacts of different types of acid and reaction conditions were also studied. To conclude, this study first confirmed the viability of enriching P2O5 from low-grade ores through organic acid leaching the carbonaceous part by experimental data, and the experimental results will provide an essential scientific support for further upgrade of the technology to commercial scale utilization.

Download Full-text

The Reduction Behavior of Ocean Manganese Nodules by Pyrolysis Technology Using Sawdust as the Reductant

Minerals ◽

10.3390/min10100850 ◽

2020 ◽

Vol 10 (10) ◽

pp. 850 ◽

Cited By ~ 1

Author(s):

Xiang-yi Deng ◽

Dong-sheng He ◽

Ru-an Chi ◽

Chun-qiao Xiao ◽

Jin-gang Hu

Keyword(s):

Activation Energy ◽

High Efficiency ◽

Acid Leaching ◽

Reduction Process ◽

Reduction Reaction ◽

Pyrolysis Process ◽

Manganese Nodules ◽

Valuable Metals ◽

Shrinking Core ◽

Isothermal Kinetic

Ocean manganese nodules, which contain abundant Cu, Co, Ni and Mn resources, were reduced using biomass (sawdust) pyrolysis technology. Valuable metals were further extracted by acid leaching after the reduction process with high efficiency. The effects of sawdust dosage, reduction temperature, and time were investigated to obtain optimal operating parameters. The extraction rates of Mn, Cu, Co, and Ni reached as high as 96.1%, 91.7%, 92.5%, and 94.4%, respectively. Results from TGA show that the main pyrolysis process of sawdust occurs at temperature range of 250–375 °C with a mass loss of 59%, releasing a large amount of volatile substances to reduce the ocean manganese nodules. The pyrolysis activation energy of sawdust was calculated to be 52.68 kJ∙mol−1 by the non-isothermal kinetic model. Additionally, the main reduction reaction behind the main sawdust pyrolysis process was identified by the comparison of the assumed and actual TG curve. The thermodynamic analysis showed that the high valence manganese minerals were gradually reduced to Mn2O3, Mn3O4, and MnO by CO generated from sawdust pyrolysis. The shrinking core model showed that the reduction process is controlled by the surface chemical reaction with activation energy of 45.5 kJ∙mol−1. The surface of reduced ore and acid leached residue exhibited a structure composed of relatively finer pores and rougher morphology than the raw ore.

Download Full-text

Kinetic Study of the Dissolution of Tunisian Natural Phosphate or Francolite in Industrial Phosphoric Acid

JOURNAL OF ADVANCES IN CHEMISTRY ◽

10.24297/jac.v6i1.6585 ◽

2017 ◽

Vol 6 (1) ◽

pp. 908-916 ◽

Cited By ~ 4

Author(s):

Ahmed CHAABOUNI

Keyword(s):

Activation Energy ◽

Phosphoric Acid ◽

Kinetic Study ◽

Rate Constant ◽

Calcium Sulfate ◽

Shrinking Core Model ◽

Natural Phosphate ◽

Rate Of Dissolution ◽

Mineral Acids ◽

Shrinking Core

A kinetic study of dissolution of Tunisian natural phosphate or francolite whose particles have a mesoporous texture inindustrial phosphoric acid is carried out. Therefore, We focused on the study of the influence of certain parameters thatare close to those used in plants producing phosphoric acid which are the stirring speed (300, 500 and 700 rounds perminute), concentration of phosphoric anhydride (25, 30 and 35 percent of P2O5), and the temperature (60, 70 and 80degrees Celsius); we note that the rate of dissolution of this phosphate rises by increasing the precedent parameters.Because of the complexity of the study of the dissolution of phosphate in mineral acids. Several different published kineticmodels giving different expressions of speed versus time. The shrinking core model is the appropriate model used in ourwork in a solution where there is no calcium sulfate to calculate the rate constant k and the activation energy Ea = 3.3946Kcal/mol of this phosphate.

Download Full-text

Kinetic Study on the SO2 Adsorption using CuO/γ-Al2O3 Adsorbent

BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS ◽

10.9767/bcrec.11.1.425.93-100 ◽

2016 ◽

Vol 11 (1) ◽

pp. 93 ◽

Cited By ~ 7

Author(s):

David Bahrin ◽

Subagjo Subagjo ◽

Herri Susanto

Keyword(s):

Kinetic Study ◽

Reaction Rate ◽

Frequency Factor ◽

Reaction Rate Constant ◽

Reaction Engineering ◽

Test Model ◽

Cu Content ◽

Activity Test ◽

So2 Adsorption ◽

Shrinking Core

Adsorbent CuO/g-Al2O3 for adsorption of SO2 were prepared by impregnating Cu(NO3)2.3H2O solution. Five types of adsorbent were obtained 5Cu (intended Cu concentration of 5%, actual of 4.92%), 8Cu (7.68%), 15Cu(14.13%), 22Cu (20.80%) and 27Cu (25.80%). For activity test, model gas containing SO2 with a concentration of about 0.755 mol/m3 were passed through the bed of 1 gram adsorbent at a flow rate in the range of 1.4-1.8 mL/s. Adsorption of SO2 were carried out at a constant temperature of 300, 350, 400 or 450 °C. Increasing sulfur loadings (gram of sulfur per gram of adsorbent) were observed with increasing adsorption temperatures, but not with increasing Cu content in the adsorbent. Among those types, adsorbent of 8Cu was considered as the best with respect to the sulfur loading (3 g of sulfur per 100 g of adsorbent). Adsorbent 5Cu had actually a better sulfur loading, but it was suspected being contributed also by adsorption of SO2 on Al2O3. The shrinking core model was used in the kinetic study of adsorption using 8Cu and with additional assumption of a spherical particle. Compared to film diffusion and pore diffusion controlling step models, the reaction rate limitation was the best to fit the experimental data. The reaction rate constant for this model at temperatures of 300, 350, 400 and 450 °C were 0.022, 0.038, 0.042, and 0.059 kg.m.mol-1.min-1, respectively. The activation energy was 21.25 kJ.mol-1 and the frequency factor was 2.02 min-1. Copyright © 2016 BCREC GROUP. All rights reservedReceived: 10th November 2015; Revised: 29th February 2016; Accepted: 29th February 2016How to Cite: Bahrin, D., Subagjo, S., Susanto, H. (2016). Kinetic Study on the SO2 Adsorption using CuO/γ-Al2O3 Adsorbent. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1): 93-100. (doi:10.9767/bcrec.11.1.425.93-99)Permalink/DOI: <a href="http://dx.doi.org/10.9767/bcrec.11.1.425.93-99">http://dx.doi.org/10.9767/bcrec.11.1.425.93-99</a>

Download Full-text

Effect of water on wood liquefaction and the properties of phenolated wood

Holzforschung ◽

10.1515/hf.2005.101 ◽

2005 ◽

Vol 59 (6) ◽

pp. 628-634 ◽

Cited By ~ 9

Author(s):

Seung-Hwan Lee ◽

Siqun Wang

Keyword(s):

Activation Energy ◽

Reaction Temperature ◽

Weight Ratio ◽

Flexural Properties ◽

Phenol Content ◽

Reaction Conditions ◽

Wood Residue ◽

Wood Liquefaction ◽

Temperature Time ◽

Phenolated Wood

Abstract The effects of water on wood liquefaction were investigated under various reaction conditions: reaction temperature, time, and wood/phenol weight ratio. Although the addition of water decreased the reaction temperature and reduced the liquefaction rate and combined phenol content of the resulting phenolated wood, residue of <20% and a combined phenol content of >95% were obtained by controlling the reaction conditions. The addition of water suppressed an increase in the combined phenol content and molecular weight by a recondensation reaction observed in liquefaction in the absence of water under the same reaction conditions. Phenolated wood obtained in the presence of water showed comparable thermoflow properties and slightly higher activation energy for cure when compared with phenolated wood obtained in the absence of water. Moldings from both phenolated woods showed comparable flexural properties to those of moldings from commercial Novolak resin.

Download Full-text

Production of 1-Butyl-3-Methylimidazolium Acetate [Bmim][Ac] Using 1-Butyl-3-Methylimidazolium Chloride [Bmim]Cl and Silver Acetate: A Kinetic Study

10.5772/intechopen.96569 ◽

2021 ◽

Author(s):

Samir I. Abu-Eishah ◽

Saber A.A. Elsuccary ◽

Thikrayat H. Al-Attar ◽

Asia A. Khanji ◽

Hifsa P. Butt ◽

...

Keyword(s):

Activation Energy ◽

Ionic Liquid ◽

Kinetic Study ◽

Rate Constant ◽

Experimental Work ◽

Silver Chloride ◽

Reaction Rate Constant ◽

Silver Acetate ◽

New Process ◽

Very High

Since most of the literature alternatives used to produce the ionic liquid 1-butyl-3-methylimidazolium acetate [Bmim][Ac] are very slow and require different solvents, we have used in this work a new process to produce the [Bmim][Ac] by the reaction of the ionic liquid 1-butyl-3-methylimidazolium chloride [Bmim]Cl with silver acetate (AgAc) where silver chloride (AgCl) precipitates as a by-product. The genuine experimental work and kinetic analyses presented here indicate that the reaction rate constant k = 7.67x1012 e(−79.285/RT). That is, the Arrhenius constant k o = 7.67x1012 L/mol.s and the activation energy E a = 79.285 kJ/mol. The very high value of the Arrhenius constant indicates that the reaction of [Bmim]Cl with silver acetate to produce [Bmim][Ac] and silver chloride is extremely fast.

Download Full-text

Thermogravimetry of the Steam Gasification of Calluna vulgaris: Kinetic Study

Catalysts ◽

10.3390/catal11060657 ◽

2021 ◽

Vol 11 (6) ◽

pp. 657

Author(s):

José María Encinar ◽

Juan Félix González ◽

Sergio Nogales-Delgado

Keyword(s):

Kinetic Study ◽

Raw Materials ◽

Biomass Conversion ◽

Calluna Vulgaris ◽

Thermal Conversion ◽

Positive Influence ◽

Steam Gasification ◽

Conversion Model ◽

Oil Reserves ◽

Shrinking Core

On account of the continuous decrease in oil reserves, as well as the promotion of sustainable policies, there is an increasing interest in biomass conversion processes, which imply the search for new raw materials as energy sources, like forestry and agricultural wastes. On the other hand, gasification seems to be a suitable thermal conversion process for this purpose. This work studied the thermogravimetry of the steam gasification of charcoal from heather (Calluna vulgaris) in order to determine the kinetics of the process under controlled reaction conditions. The variables studied were temperature (from 750 to 900 °C), steam partial pressure (from 0.26 to 0.82 atm), initial charcoal mass (from 50 to 106 mg), particle size (from 0.4 to 2.0 mm), N2 and steam volumetric flows (from 142 to 446 mL·min−1) and catalyst (K2CO3) concentration (from 0 to 10% w/w). The use of the shrinking core model and uniform conversion model allowed us to determine the kinetic parameters of the process. As a result, a positive influence of catalyst concentration was found up to 7.5% w/w. The kinetic study of the catalytic steam gasification showed activation energies of 99.5 and 114.8 kJ·mol−1 and order of reactions (for steam) of 1/2 and 2/3.

Download Full-text

Kinetic Study of Esterification of Lactic Acid with Isobutanol and n-Butanol Catalyzed by Ion-exchange Resins

Chinese Journal of Chemical Engineering ◽

10.1016/s1004-9541(08)60276-1 ◽

2009 ◽

Vol 17 (5) ◽

pp. 773-780 ◽

Cited By ~ 38

Author(s):

Yixin QU ◽

Shaojun PENG ◽

Shui WANG ◽

Zhiqiang ZHANG ◽

Jidong WANG

Keyword(s):

Lactic Acid ◽

Ion Exchange ◽

Kinetic Study ◽

Ion Exchange Resins ◽

Exchange Resins

Download Full-text

Superior Degradation Performance of Nanoporous Copper Catalysts on Methyl Orange

Metals ◽

10.3390/met11060913 ◽

2021 ◽

Vol 11 (6) ◽

pp. 913

Author(s):

Jinyi Wang ◽

Sen Yang

Keyword(s):

Activation Energy ◽

Methyl Orange ◽

High Efficiency ◽

Low Cost ◽

Degradation Process ◽

Copper Catalysts ◽

Reaction Rate Constant ◽

Nanoporous Structure ◽

Intra Particle Diffusion ◽

Different Temperatures

The development of low-cost and high-efficiency catalysts for wastewater treatment is of great significance. Herein, nanoporous Cu/Cu2O catalysts were synthesized from MnCu, MnCuNi, and MnCuAl with similar ligament size through one-step dealloying. Meanwhile, the comparisons of three catalysts in performing methyl orange degradation were investigated. One of the catalysts possessed a degradation efficiency as high as 7.67 mg·g−1·min−1. With good linear fitting by the pseudo-first-order model, the reaction rate constant was evaluated. In order to better understand the degradation process, the adsorption behavior was considered, and it was divided into three stages based on the intra-particle diffusion model. Three different temperatures were applied to explore the activation energy of the degradation. As a photocatalytic agent, the nanoporous structure of Cu/Cu2O possessed a large surface area and it also had low activation energy, which were beneficial to the excellent degradation performance.

Download Full-text