[Cwin]

I was browsing wikipedia and I came across this:

2 MnO2 + C → 2 MnO + CO2

From my knowledge of chemistry, substances usually don't react when both reactants are in solid form because the electrons are locked away in a structure. In this case, how would the reaction proceed?

[Arctic-Nation]

That's because the reaction written down as such isn't entirely correct. In a blast furnace, metal oxides are reacted with CO gas (which is produced in situ from the incomplete burning of coal), resulting in the formation of molten metal and CO₂. No solid/solid reactions take place.

[Mitch]

As Arctic-Nation implied this only happens at very high temperatures and not by simply touching the two solids together at room temperature.