Browsing by Author "Motasim, Mahmoud"

Now showing 1 - 5 of 5

Artificial Neural Network Analysis of Titanium Dissolution Kinetics in a Sustainable DL-Malic Acid and Sodium Fluoride System: a Fundamental Study Using the Rotating Disc Method
(Taylor & Francis Ltd, 2025) Motasim, Mahmoud; Abbaker, Ahmed; Agacayak, Tevfik; Aydogan, Salih; Boyrazli, Mustafa; Abbas, Mohaid; Seifelnassr, Ahmed A. S.
This investigation presents a comprehensive kinetic analysis of titanium dissolution utilising DL-malic acid (a 50/50 mix of D- and L- isomer off malic acid) in conjunction with sodium fluoride solution, offering an innovative alternative to conventional chloride and sulphate methodologies. The experimental protocol employed a rotating disc apparatus to elucidate dissolution kinetics under systematically varied parameters, including angular velocity (rad/min), disc surface area (cm(2)), temperature (degrees C), and molar concentrations of DL-malic acid and sodium fluoride. A sophisticated Artificial Neural Network (ANN) architecture, implementing back-propagation methodology through the Levenberg-Marquardt algorithm with a multilayer {6-10-1} configuration, was developed to predict titanium dissolution behavior. Experimental findings demonstrated that sodium fluoride concentration predominantly influenced dissolution kinetics, manifesting a chemical reaction order of 0.674. The investigation substantiated the theoretical framework of the Levich equation within the rotating disc paradigm. The ANN model demonstrated exceptional predictive capability, achieving correlation coefficients (R-2) of 0.995, 0.994, 0.996, and 0.995 for training, validation, testing, and aggregate datasets. The experimentally determined activation energy of 23 kJ/mol conclusively indicated a diffusion-controlled reaction mechanism, providing fundamental insights into the mass transfer phenomena governing the dissolution process. Cette & eacute;tude pr & eacute;sente une analyse cin & eacute;tique compl & egrave;te de la dissolution du titane utilisant l'acide malique-DL (un m & eacute;lange 50/50 d'isom & egrave;res D et L de l'acide malique) en conjonction avec une solution de fluorure de sodium, offrant un choix innovateur par rapport aux m & eacute;thodologies conventionnelles au chlorure et au sulfate. Le protocole exp & eacute;rimental a utilis & eacute; un appareil & agrave; disque rotatif pour & eacute;lucider la cin & eacute;tique de dissolution, avec des param & egrave;tres vari & eacute;s syst & eacute;matiquement, notamment la vitesse angulaire (rad/min), la superficie du disque (cm2), la temp & eacute;rature (degrees C) et les concentrations molaires de l'acide malique-DL et de fluorure de sodium. On a d & eacute;velopp & eacute; une architecture sophistiqu & eacute;e de r & eacute;seau neuronal artificiel (RNA), mettant en oe uvre une m & eacute;thodologie de r & eacute;tropropagation au moyen de l'algorithme de Levenberg-Marquardt avec une configuration multicouche {6-10-1}, afin de pr & eacute;dire le comportement de dissolution du titane. Les r & eacute;sultats exp & eacute;rimentaux ont d & eacute;montr & eacute; que la concentration en fluorure de sodium influen & ccedil;ait principalement la cin & eacute;tique de dissolution, produisant un ordre de r & eacute;action chimique de 0.674. L'& eacute;tude a corrobor & eacute; le cadre th & eacute;orique de l'& eacute;quation de Levich dans le paradigme du disque rotatif. Le mod & egrave;le de RNA a d & eacute;montr & eacute; une capacit & eacute; exceptionnelle de pr & eacute;diction, atteignant des coefficients de corr & eacute;lation (R2) de 0.995, 0.994, 0.996 et 0.995 pour l'apprentissage, la validation, les essais et les ensembles de donn & eacute;es agr & eacute;g & eacute;es. L'& eacute;nergie d'activation de 23 kJ/mol d & eacute;termin & eacute;e exp & eacute;rimentalement a indiqu & eacute; de mani & egrave;re concluante un m & eacute;canisme de r & eacute;action contr & ocirc;l & eacute; par diffusion, fournissant des informations fondamentales sur les ph & eacute;nom & egrave;nes de transfert de masse gouvernant le proc & eacute;d & eacute; de dissolution.
Citation - WoS: 1
Citation - Scopus: 1
The Investigation of Metallic Silver Dissolution Kinetics Using DL-Malic Acid With Hydrogen Peroxide Solution as an Eco-Friendly Leaching System: The Rotating Disc Method
(Springer, 2025) Motasim, Mahmoud; Boyrazli, Mustafa; Aydogan, Salih; Agacayak, Tevfik; Ali, Babiker
Although cyanidation remains widely employed for silver recovery due to its cost-effectiveness, it presents serious environmental and health hazards. In this study, the dissolution kinetics of silver were investigated in an environmentally benign leaching system composed of DL-malic acid and hydrogen peroxide, employing the rotating disc method. High-purity silver discs (99.99 pct) were used to examine the effects of rotation speed, disc surface area, temperature, and the concentrations of DL-malic acid and hydrogen peroxide on the leaching rate. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) were conducted to characterize the silver surface before and after leaching. Additionally, contact angle measurements were performed to evaluate the interfacial interaction between the leaching solution and the silver surface. The results demonstrated that the dissolution rate increased with temperature, rotation speed, hydrogen peroxide concentration, and surface area. However, elevated concentrations of DL-malic acid resulted in the formation of a passivating layer on the silver surface, likely due to chelation effects, which significantly impeded the access of protons (H+) to the silver surface, thereby reducing the dissolution rate. Contact angle analysis further indicated reduced wettability at higher DL-malic acid concentrations, with values reaching up to 87.80 deg. XRD analysis confirmed the partial oxidation of the silver surface, forming Ag2O. The reaction was determined to be chemically controlled, with an activation energy of 44.14 kJ/mol.
Ore Characterization and Quality Control Aspects of Gold Cyanidation: the Cil Plant as a Case Study in Sudan
(Berg Fac Technical Univ Kosice, 2024) Motasim, Mahmoud; Agacayak, Tevfik; Osman, Walid
Mineralogical and chemical studies are key to mineral processing because they present the problem of low-grade ores to the metallurgist or mineral processing engineer. Quality control operations are also significant in obtaining good products by flowing the sequences of processes. In this study, the ore was characterized, and quality control issues were discussed. Results showed that the gold grade is 9.7 g/ton, the minerals are mainly silicates, and the pH of the ore is high, which means that without pre-treatment, i.e., roasting, oxidation, etc., it can be cyanided directly. Therefore, the CIL plant could recover more than 90% gold. In quality control of the plant, from each unit at a different time, a representative sample and an accumulative sample were collected and then subjected to analysis like fineness and solid percentage, moisture, and conditions of cyanidation. The results showed steady operation conditions for each unit.
Citation - WoS: 1
Citation - Scopus: 1
The Potential of Sudanese Refractory Gold Ores Characterization and Pre-Treatment in Ariab Mines (vms) in Red Sea (sudan)
(BERG FAC TECHNICAL UNIV KOSICE, 2023) Motasim, Mahmoud; Ağaçayak, Tevfik; Fathalrhman, Mohammed; Elhadi, Eltahir; El-GAK, Amin; Awdekarim, Abdelshakour; Seifelnasr, Ahmed Abdullah Sadeek
This laboratory work demonstrates the ability to characterize and pretreat Sudanese refractory gold ores at Ariab mines to extract the gold with optimal parameters. Characterization studies were performed by AAS, XRF and XRD analysis to assess the abundance of elements and mineral phases. In addition, the acidity of the ore was examined to estimate the effective amount of lime. The ore was subjected directly to cyanidation without any pre-treatment. High oxidation reagent processes were carried out to pre-treat the ore. Chemical analysis results show the gold grade to be 1.37 g/t. In addition, the ore contained 51.78% Fe2O3, 43.40% SO3, 2.39% CuO, 1.47% SiO2, 0.35% Cr2O3, 0.17% CaO, 0.08% As2O3, 0.06% ZnO and 0.06% MnO. The XRD result shows that the ore phases are Pyrite (FeS2), Chatkaite (Cu6Fe+2Sn2S2) and Quartz (SiO2). The investigations of direct cyanidation elucidated that the ore can consume a high amount of cyanide with unsatisfactory recoveries for gold (Exgold & LE;39.41%). The influence of the cyanide concentration, pulp density (% by weight), leaching time hr, agitator speed and pH were examined in direct cyanidation experiments. In pre-treatment experiments, the effect of hydrogen peroxide (H2O2) and concentrations on gold recovery was studied. The pre-treatment of the ore with H2O2 achieved a good impact on the gold extraction performance. The higher gold extraction was obtained at hydrogen peroxide (H2O2) 300 ppm, cyanide concentration 3500 ppm, leaching time 10 hr, pH=10.5 and pulp density 40%.
Citation - WoS: 2
Citation - Scopus: 2
Reaction Kinetics of Molybdenum Dissolution by Hydrogen Peroxide in Acidic and Alkaline Solutions Using Tartaric Acid and Sodium Hydroxide: a Semi-Empirical Model With Rotating Disc Method
(WILEY, 2025) Motasim, Mahmoud; Agacayak, Tevfik; Eker, Yasin Ramazan; Aydoğan, Salih; Abbaker, Ahmed
Molybdenum is an amphoteric metal that dissolves in both acidic and alkaline solutions. This fundamental study explores a sustainable process for the dissolution of molybdenum, focusing on the reaction kinetics in H2O2, H2O2-NaOH, and H2O2-C4H6O6 solutions. A rotating disc method was applied with the Levich's equation. Semi-empirical models with activation energy were developed for the H2O2-NaOH and H2O2-C4H6O6 solutions. The study examined the effects of rotating speed, disc surface area, temperature, H2O2, NaOH, and C4H6O6 concentrations, along with rotating speed, disc surface area, and temperature. Hydrogen peroxide significantly impacted molybdenum dissolution rates across all three solutions. The reaction order of hydrogen peroxide concentration in the H2O2 solution was greater than that of the H2O2-NaOH and H2O2-C4H6O6 solutions. The complex of molybdenum peroxo was formed in H2O2 and H2O2-NaOH solutions but decomposed at a temperature >= 50 degrees C. The activation energies were determined to be 49.90, 43.60, and 41.10 kJ/mol for the H2O2, H2O2-NaOH, and H2O2-C4H6O6 solutions. Molybdenum dissolution in H2O2-NaOH solution. image