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Showing 3 results for M. Sh. Bafghi

A. Zakeri,, M. Sh. Bafghi, Sh. Shahriari,
Volume 4, Issue 3 (Summer &Autumn 2007 2007)

Abstract: In this paper, kinetics of reductive leaching of manganese dioxide ore by ferrous ion in sulfuric acid media has been examined. Experimental results show that increasing temperature from 20 to 60 °C and decreasing ore particle size from −16+20 to −60+100 mesh considerably enhance both the dissolution rate and efficiency. Molar ratios of Fe2+/MnO2 and H2SO4/MnO2 in excess to the stoichiometric amounts were needed for successful manganese dissolution. Under the optimum condition (ore particle size of −60+100 mesh, Fe2+/MnO2 molar ratio of 3.0, H2SO4/MnO2 molar ratio of 2.0) manganese could be extracted with over 95% efficiency by 20 minutes leaching at room temperature. A kinetic analysis based on dimensionless time method showed that shrinking core – ash diffusion control model fits the experimental results reasonably well. Value of activation energy was found to be 28.1 kJ/mole for the proposed mechanism.
A. H. Emami, M. Sh. Bafghi, J. Vahdati Khaki, A. Zakeri,
Volume 6, Issue 2 (Spring 2009 2009)


the changes of BET surface area of a mineral substance during intensive grinding process. Validity of the proposed

model was tested by the experiments performed using a natural chalcopyrite mineral as well as the published data. It

was shown that the model can predict the experimental results with a very good accuracy and can be used to predict

what may happen under the similar experimental conditions.

Based on experimental observations, a model has been developed to describe the effect of grinding time on

M. Sh. Bafghi, A. Yarahmadi, A. Ahmadi, H. Mehrjoo,
Volume 8, Issue 3 (september 2011 2011)


the reduction agent. Pellets of barite ore containing about 95% BaSO

temperature, time, ore grain size and the type and grain size of the carbon materials. Graphite, coke and charcoal have

been used as the reducing agent and the reduction experiments have been performed in the temperature range of 925-

1150 °C. Apart from conducting the experiments using pellets made of ore powder, kinetic analysis of the experimental

data by use of the reduced (dimensionless) time method has been another unique feature of the present study.

Experimental results show that grain size of either carbon material or barite ore has not appreciable effect on the

reaction rate. Kinetic analysis of the experimental data revealed the rate is strongly controlled by the chemical reaction

of carbon gasification (Boudouard reaction). The reaction rate is very considerably related to the type of carbon

material so that the activation energy varies from 15.6 kcal.mol



The present study deals with the reduction of barium sulfate (Barite) to barium sulfide by use of carbon as4 has been reduced under different conditions of-1 for charcoal to 26.3 kcal.mol-1 for graphite and 20.8-1 for coke. This behavior provides further support for the postulated reaction mechanism, i.e., carbon

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