Dried leaves - Novel reductant for acid leaching of manganese ore

Abstract

In the present investigation results on the use of dried leaves as a reductant for manganese ore leaching is reported. A complete flow-sheet consisting of steps such as reductive acid leaching, enrichment of leach solution by recycling, iron removal and crystallization has been developed for the preparation of manganese sulphate monohydrate from manganese ore of Gujarat Mineral Development Corporation (GMDC), Ahmedabad, India. During leaching effects of pulp density, amount of acid, temperature, particle size of ore and reductant to ore ratio were studied. Almost total manganese extraction could be achieved under the following conditions: leaching time 8h, H(2)SO(4) 5% (v/v), pulp density 10% (w/v), temperature 95 degrees C and dried leaves to ore ratio 0.5. Mn enriched (>90 g/L Mn) leach liquor was obtained by recycling the leach solution twice. The solution so obtained was purified by pH adjustment using lime slurry. A schematic flowsheet for the preparation of manganese sulphate monohydrate crystal is given.