I have completed the hydrochloric acid treatment line for iron oxide. It converts hematite and limonite into iron, and oxygen (which is almost like garbage).
But to get iron, it is more attractive and much simpler to process sulfides than to process hematite.
Even to get titanium, there are more attractive alternatives such as bauxite.
It may be a bit impractical, but why not have a byproduct of the hydrochloric acid treatment stage at Bath, like slag in real-life iron smelting?
These slags contain SiO2, MnO, Al2O3, and so on. And in some cases, TiO2 may also remain in them.
Of course I could simply use MineTweaker.
But as a game, I think it is more fun to have rewards for taking on more difficult challenges.
(I used a translation software, so sorry if it’s not clear.)