scholarly journals Treatment of black copper with the use of iron scrap - part I

2020 ◽  
Vol 74 (4) ◽  
pp. 237-245
Author(s):  
Norman Toro ◽  
Kevin Pérez ◽  
Manuel Saldaña ◽  
Eleazar Salinas-Rodríguez ◽  
Pía Hernández
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Acidic Medium ◽  
Mineral Resources ◽  
Reducing Agent ◽  
Iron Scrap ◽  
Effect Of Particle Size ◽  
High Concentrations ◽  
Kinetics Of Dissolution ◽  
Kinetics Of

Currently, there is a large amount of mineral resources not being exploited in large copper minings, a clear example are black copper minerals. These resources are generally not incorpo-rated into the extraction circuits or are not treated, either in stocks, leach pads, or debris. These exotic minerals have considerable amounts of Cu and Mn, which are commercially very attractive. They are refractory to conventional leaching processes, therefore, the use of reducing agents is necessary for treatment of these minerals in order to dissolve the present MnO2, which in turn allows Cu extraction. In this research, iron scrap Fe0 was used as a reducing agent for the dissolution of Mn from a black copper mineral in an acidic medium and compared to previous studies of the use of Fe2+ under the same conditions. In addition, the effects of a pretreatment process (agglomeration and curing) by adding NaCl are investigated in order to favor the reduction of MnO2. Finally, it was discovered that there is a higher kinetics of dissolution of Mn when working with Fe0 in short periods of time, although similar extraction efficiencies are obtained after prolonged times. The pretreatment process by adding NaCl resulted in increased Mn extraction in short periods of time (30 min). At applying high concentrations of the reducing agent, the effect of particle size on the dissolution rate of MnO2 was shown to be insignificant.

scholarly journals The effect of particle size on dissolution rate of fast dissolving oral film containing diclofenac sodium

Pharmaciana ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 211
Author(s):  
Fitrianti Darusman ◽  
Nyayu Ista Yulita ◽  
Gita Cahya Eka Darma
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Diclofenac Sodium ◽  
Effect Of Particle Size

Experimental Investigation of the SO2 Abatement Capacity of South African Calcium-Based Materials

2007 ◽  
Author(s):  
Zachary O. Siagi ◽  
Makame Mbarawa
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
South African ◽  
Efficient Operation ◽  
Shrinking Core ◽  
Caco3 Particle ◽  
Ph Stat ◽  
Kinetics Of ◽  
Different Sources ◽  
So2 Absorption

One of the most important steps in the wet limestone-gypsum flue gas desulphurization (WFGD) process is CaCO3 dissolution, which provides the dissolved alkalinity necessary for SO2 absorption. Accurately evaluating the CaCO3 dissolution rate is important in the design and efficient operation of WFGD plants. In the present work, the dissolution of limestone from different sources in South Africa has been studied in a pH-stat apparatus under conditions similar to those encountered in wet FGD processes. The influence of various parameters such as the reaction temperature (30 ≤ T ≤ 70°C), CaCO3 particle size (25 ≤ dp ≤ 63μm), solution acidity (4 ≤ pH ≤ 6), and chemical composition were studied in order to determine the kinetics of CaCO3 dissolution. The results obtained indicate that the dissolution rate increased with a decrease in particle size and an increase in temperature. The dissolution curves were evaluated in order to test the shrinking core model for fluid–solid systems. The analysis indicated that the dissolution of CaCO3 was controlled by chemical reaction, i.e. 1 − (1 − X)1/3 = kt.

scholarly journals Pure Trans-Resveratrol Nanoparticles Prepared by a Supercritical Antisolvent Process Using Alcohol and Dichloromethane Mixtures: Effect of Particle Size on Dissolution and Bioavailability in Rats

Antioxidants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 342 ◽  
Author(s):  
Eun-Sol Ha ◽  
Heejun Park ◽  
Seon-Kwang Lee ◽  
Woo-Yong Sim ◽  
Ji-Su Jeong ◽  
...  
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Oral Bioavailability ◽  
In Vitro Dissolution ◽  
Absolute Bioavailability ◽  
Simulated Gastric Fluid ◽  
Mean Particle Size ◽  
Supercritical Antisolvent ◽  
Effect Of Particle Size

The aim of this study was to prepare pure trans-resveratrol nanoparticles without additives (surfactants, polymers, and sugars) using a supercritical antisolvent (SAS) process with alcohol (methanol or ethanol) and dichloromethane mixtures. In addition, in order to investigate the effect of particle size on the dissolution and oral bioavailability of the trans-resveratrol, two microparticles with different sizes (1.94 μm and 18.75 μm) were prepared using two different milling processes, and compared to trans-resveratrol nanoparticles prepared by the SAS process. The solid-state properties of pure trans-resveratrol particles were characterized. By increasing the percentage of dichloromethane in the solvent mixtures, the mean particle size of trans-resveratrol was decreased, whereas its specific surface area was increased. The particle size could thus be controlled by solvent composition. Trans-resveratrol nanoparticle with a mean particle size of 0.17 μm was prepared by the SAS process using the ethanol/dichloromethane mixture at a ratio of 25/75 (w/w). The in vitro dissolution rate of trans-resveratrol in fasted state-simulated gastric fluid was significantly improved by the reduction of particle size, resulting in enhanced oral bioavailability in rats. The absolute bioavailability of trans-resveratrol nanoparticles was 25.2%. The maximum plasma concentration values were well correlated with the in vitro dissolution rate. These findings clearly indicate that the oral bioavailability of trans-resveratrol can be enhanced by preparing pure trans-resveratrol nanoparticles without additives (surfactants, polymers, and sugars) by the SAS process. These pure trans-resveratrol nanoparticles can be applied as an active ingredient for the development of health supplements, pharmaceutical products, and cosmetic products.

scholarly journals Effect of particle size on adsorption kinetics of water vapor on porous aluminium oxide material

2019 ◽  
Vol 1145 ◽  
pp. 012033 ◽  
Author(s):  
S Reshetnikov ◽  
Zh Budaev ◽  
A Livanova ◽  
E Meshcheryakov ◽  
I Kurzina
Keyword(s):  
Particle Size ◽  
Water Vapor ◽  
Adsorption Kinetics ◽  
Aluminium Oxide ◽  
Oxide Material ◽  
Effect Of Particle Size ◽  
Kinetics Of

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.

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