I am new here, but as a lurker, and as a Lurker, I have seen few and far between suggestions about the addition of Aluminum. Many, and by many, I mean all, of those suggestions floundered. Perhaps, with a bit of elbow grease amd luck, this onw will not suffer the same fate. Ladies and Gentlemen, I present to you: 

(Facts of Aluminium before uses in the game)

Aluminium: 

At low temperatures, aluminum is not brittle. The opposite, in fact. Aluminum is stronger at lower temperatures. Problem is, high temperature weaken the strength of aluminum, making it a somewhat brittle metal at around 100C, but must escalate. 

Just like the basic metl, Aluminium is a conductor of heat and electricity. 

Aluminium is also capable of reflecting light AND heat. 

Aluminium is also capable of strengthening its resistance to corrosion by using oxygen in the air and shielding itself from possible harm. The shield can also repair itself if/when damaged. Take this into consideration for in-game usage. The 'shield' is called aluminium oxide, which is what happens when aluminum corrodes over time. The dust is what keeps the aluminium from further corrosion. Does not fall away when 'attached' to aluminium. Will fall away if attached to a different material. 

Unfortunately, Aluminium will corrode quite quickly when faced with a large dosage of acid, but with a small dosage, it will not. 

If magnetism becomes an addition, it will not work on Aluminium. 

(Now for in-game)

Aluminum oxide becomes a thing after aluminum becomes brittle at high temperatures. The aluminum oxide then pushes the low melting point of aluminum higher because it's stronger. The melting point of aluminum oxide is 2,072C. Therefore, aluminium oxide is a great addition because it makes aluminum stronger. 

Aluminium powder can be used with iron oxide (rust) to create thermite. The "powder" of aluminum is just shevn aluminum, but to make such a thing in tpt is generally impossible. 

Aluminium can be used as a holder of regrigerant to retain the cold

Aluminium also helps keep a pc processor cool, making it a useable metal in the creation of a powder toy computer. 

Compared to Iron: 

Melting point: Alum - 658C / Iron - 1540C

Thermal Capacity: Alum - 900C / Iron - 450C

Thermal Conductivity: Alum - 230C / Iron - 75C

In-game colour: 

Secret material: Aluminium Powder - HEX(#b5b8bc) / rgb(181, 184, 188)

Aluminium - HEX(#b4b6ba) / rgb(180,182, 186)

Aluminium Oxide - HEX(#e0e2e5) / rgb(224, 226, 229)

4 digit name in TPT: 

Aluminium Powder - ALPR

Aluminium - ALUM

Aluminium Oxide - ALOD

Perhaps I am being slightly foolish in believing aluminium is a great addition, but it'd be quite interesting to see it as a conductor of heat, a cooling chamber for refrigerant, a shield against high temperature bombs

@coryman (View Post)

 As I'm not much of a scientist by nature, I'll have to look the answer to your questions up or ask a couple friends of mine. I just want to see Aluminium become an addition mainly because some metals are useless. I'll get back to later tonight or tomorrow. Just updating this post and not as a new reply. Don't want your question to hang without an answer. That'd be rude. 

If you want, during my information gathering time, you can check out my new suggestion in this forum. It's called 'Vinculum'. 

Also, thank you for being polite. A little good goes a long way. 

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Aluminum is something called a 'radiant barrier'. As aluminum is a 'shiny' metal, it reflects radiant heat rather than absorbing it. I.e., Aluminum is an insulator. 

As for reflecting light, it kind of follows the same principle. Aluminum can be made as a matte finish or a shining finish. The shining finish reflects radiant heat and light. The reflects in a linear path. Mostly when using Aluminum foil, but can also be the same for Aluminum plates and cylinder pipes. 

Hope this helped.