Im trying to get metallic Manganese for electrolisis.
(actually Im testing electrollitical Mn form MnSO4) with more or less success.
From the Wiki:
MnO2 + C → Mn + CO2
I ve some Mn oxides (high oxides) left from battery leachings for getting MnSO4.
I follow Der Alte procedure in which you burn battery MnO2 to get Mn2O3 for futher processing.
"(B1) For Zn/C cells only: put in a tin can and heat to bright red heat. All MnO2 will convert to Mn2O3 @ 700C+ and the carbon should burn off; also
zinc/ammonia complexes will drive off ammonium chloride as white clouds and worry the neighbors. Cool, treat with cold dilute acid (N/10 or less) to
get rid of any ZnO. Pour off acid, and wash. Complex but unless carried out the product will be polluted. Resultant should be mainly Mn2O3: go to step
(C)"
So the questions:
1) Is this reduction posible as for an amateur?
2) Which temperature should a mix of Carbon and MnOx used to get the reduction?
from this paper state 27 to 1227°C (pressure related)
3Mn2O3 + C = 2Mn3O4 + CO (ΔGo = - 0.25 ? 0.17T 25°-1100°)
Mn3O4 + C = 3MnO + CO (ΔGo = 110.96 ? 0.21T 25°-1244°
ΔGo = 84.35 ? 0.20T 1244°-1700°
MnO + C = Mn + CO (ΔGo = 287.6 ? 0.16T 25-1227°)
(NOTE: i do not understand this free gibs, but probably you do.)
(NOTE: I will need manganese metal for electrolitic KMnO4 production, so the least contamination of other metals - so thermite is no good)
Thermite can produce very pure metals but the MnO2 thermite is very low yield because the boiling point of Mn is about the same as the
melting point of alumina. This causes the Mn to largely boil off.
Because these carbothermic reductions are so endothermic, very high temperatures are needed (see Ellingham diagrams)
