A Facile and Cost-Effective Synthesis of Manganese Carbonate and Manganese Dioxide from Bajaur Manganese OrePages 470-482
Waheed Ur Rehman Abstract:
In the present study, manganese ore of district Bajaur, Pakistan, was evaluated for the synthesis of manganese carbonate (MnCO3) through a facile and cost-effective approach, employing hydrochloric acid (HCl) as an extractant, and soda ash (Na2CO3) as a precipitant at different temperatures and times. The optimum yield and maximum manganese content in the prepared MnCO3 was found to be 78.10% and 28.54%, respectively, at a temperature of 70oC and a time of 3 hours. MnCO3 was then calcined to manganese dioxide (MnO2) at elevated temperatures. SEM-EDX, XRD, and FTIR techniques were applied to explore the morphology, crystal structure, and purity of the developed products. The major mineral phase in MnCO3 was rhodochrosite having a cubical morphology. An increase in calcination temperature from 500 to 900oC, progressively changed MnO2 from α-MnO2 to β-MnO2 polymorph. A flowsheet has also been proposed for the commercial production of the two products.
Keywords: Manganese carbonate,
Manganese dioxide,
Rhodochrosite,
Extractant,
Precipitant,
Calcination
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