Bauxite Ore -Ore Processing-> Bauxite Powder
Bauxite Powder -Autoclave-> Sodium/Potassium Aluminate
Sodium/Potassium Aluminate -Bath-> Aluminium Hydroxide
Aluminium Hydroxide -Dryer-> Alumina Powder
Alumina Powder -Electrolyzer-> Aluminium Powder
For the Autoclave+Bath step, you need Steam for the Autoclaves. I have calculated that 16HU/t drives exactly 4 Autoclaves. You also need Sodium/Potassium Hydroxide into the Autoclave, which is fully recycled from the Bath output. It also outputs Ilmenite and Rutile (for Titanium) as by-products.
For the Electrolyzer step, you also need Carbon, etc. You also need 2 additional fluid inputs in small quantities, which is Aluminium Trifluoride and Cryolite, both of which contains Aluminium and Fluorine, and can be produced from Alumina plus Fluorite, etc.