Mehmet Copur

Kinetic Investigation of Reaction Between Colemanite Ore and Methanol

In the field of industry, it is very important that boron compounds are produced from boron ores. The aim of this study was to investigate the dissolution kinetics with carbon dioxide of colemanite in methanol medium in a pressure reactor and to derive an alternative process for producing boron compounds. Reaction temperature, stirring speed, solid/liquid ratio, pressure, and particle size were selected as parameters for the dissolution rate of colemanite. It was found that the dissolution rate increased with increase in pressure and reaction temperature, and with decrease in particle size and solid/liquid ratio. No effect of stirring speed was observed on conversion. The dissolution kinetics of colemanite were examined using both heterogeneous and homogeneous reaction models, and it was determined that the reaction rate can be described by a second-order pseudo-homogeneous reaction model. The activation energy was found to be 51.4 kJ/mol.

OPTIMIZATION OF DISSOLUTION OF ULEXITE IN (NH4)2SO4 SOLUTIONS

Abstract The Taguchi method was used to determine the optimum conditions for the dissolution of ulexite in ammonium sulphate solutions. The ranges of experimental parameters were between 60-88 °C for reaction temperature, 0.05-0.15 g.mL−1 for solid to liquid ratio, 5–20 minutes. for reaction time and (-850+600) – (−90) μm for particle size. The optimum conditions for these parameters were found to be 88 °C, 0.1 g.mL−1, −90 μm and 20 minutes, respectively. Under these conditions, the predicted and experimental dissolution percentages of ulexite in ammonium sulphate solutions were 98.60 and 98.36 per cent, respectively. On a utilisé la méthode de Taguchi pour déterminer les conditions optimales de dissolution de l’ulexite dans des solutions de sulfate d’ammonium. La gamme des paramètres expérimentaux se situait entre 60-88°C pour la température de réaction, entre 0.05−0.15 g·mL−1 pour le rapport solide–liquide, entre 5−20 min pour la durée de réaction et entre (−850+600) – (−90) μm pour la taille de particule. On a trouvé que les conditions optimales des paramètre étaient de 88°C, 0.1 g·mL−1, −90μm et 20 min, respectivement. Sous ces conditions, le pourcentages prédit et le pourcentage expérimental de dissolution de l’ulexite dans des solutions de sulfate d’ammonium étaient de 98.60 et de 98.36 pourcent, respectivement.

Determination of the Optimum Conditions for Copper Leaching from Chalcopyrite Concentrate Ore Using Taguchi Method

The optimum conditions for the extraction of copper from chalcopyrite concentrate into SO2-saturated water were evaluated using the Taguchi optimization method. High level copper recovery was obtained in an environmentally friendly process that avoids sulfur dioxide emission into the atmosphere because SO2 forming in the roasting is used in the dissolution. Experimental parameters and their ranges were chosen as follows: reaction temperature, 293–333 K; solid-to-liquid ratio, 0.025–0.15 g/mL; roasting time, 30–90 min; roasting temperature, 773–973 K; stirring speed, 400–800 rpm; and reaction time, 10–60 min. The particle size and gas flow rate were 63 µm and 10 cm3/min, respectively. The optimum conditions of the dissolution process were determined to be reaction temperature of 318 K, a solid-to-liquid ratio of 0.025 g mL−1, a roasting time of 75 min, a roasting temperature of 773 K, a stirring speed of 400 rpm, and a reaction time of 30 min. Under optimum conditions, dissolution yield of copper was 91%.

Kinetic Analysis of Retention of SO 2 Using Waste Ulexite Ore in an Aqueous Medium

This study was carried out under atmospheric pressure and examined the kinetics of retention of SO2, a toxic gas, by waste ulexite ore (WUO) from a boron concentration plant, as well as the kinetics of passing B2O3 content of WUO to solution. The parameters of temperature, solid-to-liquid ratio, particle size, gas flow rate, and stirring speed were selected for the experiments carried out in a jacketted cylindirical glass reactor. The data on retention-dissolution and an XRD graph showed that SO2 had been captured as CaSO3·0.5H2O, and that the B2O3 content of WUO had almost completely passed into the aqueous medium. A kinetic evaluation, performed with the retention-dissolution data using kinetic models for heterogenous reactions, found that the kinetics model for SO2 retention fitted diffusion through product layer control. In addition, the kinetics model for the B2O3 dissolution fitted the diffusion through product film control. Activation energies for SO2 retention in solid waste and B2O3 dissolution were 6196 J mol-1 and 15436 J mol-1 respectively.

AN OPTIMIZATION STUDY ON DISSOLUTION OF THE CALCINED COLEMANITE MINERAL IN METHYL ALCOHOL BY CO2 IN AN AUTOCLAVE SYSTEM USING TAGUCHI METHOD

The process of optimizing the dissolution of colemanite ore (2CaO.3B 2 O 3 .5H 2 O) in methyl alcohol by CO 2 in a high-pressure reactor was evaluated by using the Taguchi method. Optimum conditions for the cholemanite mineral were determined to be as follows: reaction temperature: 140°C, reaction time: 50 min, calcination time: 240 min, calcination temperature: 450 o C, solid-liquid ratio: 1/6 g.mL -1 , mixing rate: 500 cycle/min, pressure: 20 bar, grain size: -100 mesh and the amount of CaCl 2 : 7.5 g.

Determination of Optimal Conditions for Retention of Sulfur Dioxide by Waste Ulexite Ore in an Aqueous Medium

The main aim of this study was to remove sulfur dioxide (SO2), which is one of the most significant air pollutants emitted from thermal power stations, using waste ulexite ore, which cannot be recycled industrially and poses a risk for the environment. In experiments conducted at atmospheric pressure in an aqueous environment, the optimization of holding SO2 with waste ulexite ore has been investigated comprehensively and determined how much SO2 could be retained in solid waste. The Taguchi method was used to determine the optimal conditions, and the effectiveness of the parameters was identified by variance analysis. The selected parameters and their ranges were defined as temperature (293–333 K), solid to liquid ratio (0.4–0.6 g mL−1), particle size (150–600 µm), time (10–30 min), pH (5.5–7.5), and stirring speed (350–800 rpm). The optimal conditions for these parameters were determined to be 333 K, 0.45 g mL−1, −250 µm, 15 min, pH 6, and 350 rpm, respectively. Among all the parameters, temperature and pH were found to be the most effective. The results of the study revealed that SO2 can be retained in solid waste with calcium content of the boron minerals as CaSO3 · 0.5H2O and nearly whole B2O3 in the waste ulexite passes into solution. Under the optimum conditions, 86% of B2O3 passed into the solution and 75.2 L SO2 was retained by 1 kg waste ulexite ore. Thus, both B2O3 recovery and SO2 removal were materialized, while waste ulexite ore was evaluated and removed, simultaneously.

Thermal dehydration of colemanite: kinetics and mechanism determined using the master plots method

ABSTRACT Dehydration kinetics of colemanite ore were explored using thermogravimetric analysis techniques (thermogravimetry (TG)/derivative thermogravimetry (DTG)) in the range of 0–1000°C at heating rates of 2, 5, 10 and 20°C min−1 in an inert (N2) atmosphere. Kinetic triplets which were activation energy, pre-exponential factor and reaction mechanism were obtained from the TG and DTG applying six model-free (isoconversional) methods, i.e. Kissinger–Akahira–Sunose (KAS); Flyn–Wall–Ozawa (FWO); Tang, Starink and iterative KAS and iterative FWO. The researcher tested the reliability of the study method in identifying the kinetic mechanism by comparing experimental master plots to theoretical master plots. Structural and morphological properties were carried out using X-ray diffraction, Fourier transform infrared and scanning electron microscopy-energy disperse spectroscopy methodologies.

Investigation of the Thermal Decomposition Kinetics of Chalcopyrite Ore Concentrate usıng Thermogravimetric Data

The kinetics of the thermal decomposition of chalcopyrite concentrate was investigated by means of thermal analysis techniques, Thermogravimetry/Derivative thermogravimetry (TG/DTG) under ambient air conditions in the temperature range of 0–900°C with heating rates of 2, 5, 10, 15, and 20°C min−1. TG and DTG measurements showed that the thermal behavior of chalcopyrite concentrate shows a two-step decomposition. The decomposition mechanism was confirmed using X-ray diffraction (XRD), Scanning Electron Microscope (SEM)/energy-dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR) analyses. Kinetic parameters were determined from the TG and DTG curves for steps I and II by using two model-free (isoconversional) methods—Flyn–Wall–Ozowa (FWO) and Kissinger–Akahira–Sunose (KAS). The kinetic parameters consisting of Ea, A, and g(α) models of the materials were determined. The average activation energies (Ea) obtained from both models for the decomposition of chalcopyrite concentrate were 72.55 and 300.77 kJ mol−1 and the pre-exponential factors (A) were 15.07 and 29.39 for steps I and II, respectively. The most probable kinetic model for the decomposition of chalcopyrite concentrate is an first-order mechanism, i.e., chemical reaction [g(α) = (−ln(1−α))], and an Avrami–Eroeyev equation mechanism, i.e., nucleation and growth for n = 2 [g(α) = (−ln(1−α)1/2)], for steps I and II, respectively.