electrochemistry...
...Won't allow you to directly smelt aluminum by way of the Hall-Héroult process, but it will allow you to separate alkali metals like potassium and sodium from their hydroxides. You can use hydrochloric acid to turn alumina into aluminum chloride, and after carefully dehydrating it, you can then react the anhydrous aluminum chloride and sodium/potassium to yield metallic aluminum. The alkali grabbed up the chlorine from the aluminum, leaving the poor old aluminum behind.
I put this out because it's long bugged me that while most of the minerals (which aren't completely made up) are geologically plausible, native aluminum is not. Aluminum is never found naturally in metallic form; it's is just too reactive. With this, you can have your expensive aluminum, without needing a bogus natural mineral type.
Yes, the availability of native aluminum also bothered me.
As for the chemical extraction of aluminum, I remember thinking along similar lines years ago, when I was in high school. I found the concept of a strictly chemical production alternative to the
Hall-Héroult process to be interesting. Considering how abundant aluminum salts and minerals are in the Earth's crust, I thought at first that it might allow for even cheaper production of aluminum.
But the problem with using hydrochloric acid or other reducing agents is how cost prohibitive that would be. And then there's the issue of disposing/treating the end products. Such a method would
not be cheap on an industrial scale, even compared with the hundreds of thousands of Amperes consumed in industrial aluminum electrolysis cells.
Still, I could imagine a society of industrious dwarves who might be able to produce the chemicals and minerals needed, especially if aluminum is valuable enough to warrant the costs and effort. Considering that they most likely butcher lots of animals for food and leather, why couldn't they save the stomach contents from butchering and distill to make hydrochloric acid?
I do hope Mephansteras considers adding an alchemical reaction for producing aluminum and removing the possibility of finding native aluminum.
That said, under
Production and Refinement, the Wikipedia article on aluminum mentions a
new production method:
Compared to most other metals, it [aluminum] is difficult to extract from ore, such as bauxite, due to the energy required to reduce aluminium oxide (Al2O3). For example, direct reduction with carbon, as is used to produce iron, is not chemically possible, since aluminium is a stronger reducing agent than carbon. There is an indirect carbothermic reduction possible by using carbon and Al2O3, which forms an intermediate Al4C3 and this can further yield aluminium metal at a temperature of 1900-2000°C. This process is still under development. This process costs less energy and yields less CO2 than the Hall-Héroult process...
I was thinking a custom magma-powered furnace could be modded for this new process. But in-game, magma's temperature is only
1,111°C, so it does not seem realistic (on the surface). Wikipedia says
magma is usually in the range of 700°C to 1300°C, so 1111°C seams a reasonable median. Then again, there are a lot of material properties in DF - including temperature - that are unrealistic.
Consider the melting points for iron and steel:
- Pig iron melts at 12106°U = 1170°C
- Iron melts at 12768°U = 1538°C
- Steel melts at 12718°U = 1510°C
In real life, cast iron melts somewhere around 1100°C to 1375 °C, steel melts at about 1400°C and wrought iron (malleable iron) melts around 1500°C. But how can a magma-powered
Magma smelter achieve those temperatures if magma is only 1111°C? Is it the fuel added to the reaction?
Even more extreme is the
Magma glass furnace, because in-game glass has a melting point of 2000°C. And
no fuel is needed for the reaction. Taking that into consideration, the 1900-2000°C temp range to use the new, non-electrolysis method of reducing aluminum actually seems plausible.
Perhaps dwarves have exceptional furnace technology and an advanced (for a pre-industrial society) understanding of thermodynamics? Or maybe they use magic?
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