Abstract:
This work investigated the beneficiation and reductive acid leaching of manganese ore
from Rafi Local Government Area, Madaka, Niger state. The chemical analysis of the
ore shows that it contains 48.4 % MnO (37.5 % Mn). While the X- ray diffractometer
(XRD) analysis of the crude sample shows peak as that of magnosite (MnO),
hausmannite (Mn3O4), spessartine and vemuculite (Mg,Fe2+,Fe3+)3[AlSiO4)O10]
(OH)2.4H2O. The liberation size was determined and obtained in the range of +180 -125
μm, while the mesh of grind was obtained at particle size 551.59 μm. The ore was
conditioned for 5 minutes and thereafter floated for 15 minutes using different flotation
reagents. The reagents used were sodium oleate (collector) at varied concentrations of 3 g/kg, 7 g/kg and 10 g/kg; Fuel oil (frother) and Sodium silicate/water glass (dispersant)
were kept at constant concentrations of 4 g/kg and 1 g/kg respectively. The pH of the
pulp was kept at 9. Results obtained showed percentage metal recoveries of 9.29 %,
14.30 % and 19.61 %, assaying 65.20 %, 62.03 % and 61.30 % Mn respectively.
Reductive acid leaching of the beneficiated ore was carried out in sulfuric acid using
glucose as the reductant for 60 minutes. The effect of concentration of sulfuric acid at
0.2 M, 0.4 M, 0.6 M, 0.8 M and 1 M; stirring speed of 100 rpm, 200 rpm, 300 rpm,400
rpm and 500 rpm; temperature at 323 K, 333 K, 343K, 353 K and 363 K; solid-liquid
ratio at 1:4, 1:5, 1:6, 1:7 and 1:8 were observed on the leaching rate. Hence, optimum
manganese leaching of 98 % was obtained at 1 M acid concentration, 400 rpm, 363 K
and 1:8 solid-liquid leaching parameters combination
