As we all know, a majority of the Martian soil is composed of ferric oxide ($Fe_2O_3$), which is also coincidentally the formula for hematite, one of the most common ores of iron.
I think (personally) that it is a fact beyond doubt that iron is absolutely necessary to sustain a civilization anywhere, even on Mars. However, the problem is that most modern metallurgical processes regarding iron require the presence of atmospheric oxygen (ala blast furnaces) or prohibitive amounts of electricity (electric arc furnaces). Both of these are, for obvious reasons, difficult to obtain on Mars. Additionally, they both require carbon, again difficult to obtain on the Red Planet.
Now, enter thermite. Aluminum is a powerful reducing agent, and is used on Earth often to reduce $Fe_2O_3$ to molten iron. So, my question is: what if we carry aluminum to Mars and then create a thermite mixture with the soil there, which can then be ignited electrically to produce iron (this requires much less power than an EAF). Thermite can burn in oxygen-less environments, and the aluminum can be reused by electrolyzing the aluminum oxide produced. Additionally, aluminum is a lighter element than iron, and thus can be carried in larger quantities by spaceships.
Is this the best method, or is there something less convoluted and more effective? I am also open to alternatives to iron.