In our study we investigated the release mechanisms of coated oral dosage forms more deeply. The aim of the study was to monitor the buffer induced leaching out of water soluble compounds from Kollicoat SR films and to relate this process to the film properties and the release kinetics. Propranolol HCl tablets were coated with different amounts and ratios of polyvinyl acetate (Kollicoat SR) and...

In the present work, the extraction of zinc from a sphalerite concentrate using sodium nitrate as an oxidant in a sulfuric acid solution was investigated. The effective parameters such as the temperature, sulfuric acid and sodium nitrite concentrations, stirring speed, particle size, and solid/liquid (S/L) ratio were analyzed. The dissolution rate increased with increase in the sulfuric acid an...

The influence of microwave heating on the leaching kinetics of chalcopyrite and sphalerite has been investigated. Chalcopyrite is inert to many leaching agents, especially ferric ion media. This mineral is considered to be one of the largest sources of copper, in terms of the scale of availability, and copper is usually extracted by pyrometallurgical processes. However, there has recently been ...

Abstract Ultrasound-assisted chalcopyrite leaching has been reported previously, showing a noticeable improvement in kinetics. However, the effect of ultrasound on oxidation kinetics from an electrochemical perspective not addressed. This study examines ultrasonic enhancement sulfuric acid solution both conventional and electrochemistry aspects. Electrochemical techniques, including linear swee...

Bacterial leaching represents an unusual problem in biochemical engineering, because the substrate for bacterial growth is not supplied directly, but is a product of another reaction, the leaching of mineral particles. In addition, leaching is a heterogeneous reaction dependent on the particle-size distribution in the feed and on the kinetics of particle shrinkage. In this study, these effects ...

The percolation technique was used to examine the leachability of uranium from El-Sela mineralization. agglomeration effect, particle size, flow rates, free acidity, solid/liquid ratio, and ratio cobblestone effect were all studied in kinetics leaching. At a height 3.0 m within column, optimal ore found be 1:4, irrigation rate reduced 0.15 0.1L/m2/min, increasing 47.5 79%. Finally, column leach...