With 50 iron ore and 100 mineral water I can make 100 ferric solution.
I can then turn the 100 ferric solution in 12 iron ore and 50 mineral water.
That's a big loss.

The only real option to make iron and copper I see is mineral water crystallization, and then incinerate what ever backups.

I'm pretty new to the mod, but the research that gives Sulfur also unlocks Slurry, which is made from hydrochloric acid and sand in the chemical plant. Then you can use slurry filtering in an oil refinery to get pure ores along with more mineral water to crystalize.

But yes, you deliberately get more copper than iron in the early game and you'll have to incinerate.