As seen in the title, and as commented previously in the Discord GT++ channel, could it be possible to add a new fluid output hatch that holds, let's say 6 different kinds of fluids with the capacity of the single-fluid output hatch (8L for ULV, 16L for LV, 24L for MV, 32L for HV, etc. for example) for the Blast Alloy Smelter?

The reason why asking this is due to the possibility of adding recipes to the Blast Alloy Smelter, such as molten steel and molten slag from ferric ores/crushed ores/dusts, calcite dust and charcoal/coal/coke, adding a tiny bit of realism to the multiblock, as it currently outputs molten metal. With this proposal, the same Blast Alloy Smelter could be used to process another recipe while, at the same time, the output is being emptied; an example of this could be processing molten iron while in the output there is molten silicon being drained: the recipe can be performed due to having an empty fluid container avaible.

Its GUI could be the same as the fluid output hatch with the different fluids in it. For its functionality could be set as until one kind of fluid has not been emptied it cannot output the next one (special treatment would be the EnderIO ender fluid conduits, due to its capability of carrying multiple kinds of fluids at the same time).

So, summarizing, new idea: Multi-fluid output hatch for the Blast Alloy Smelter

• New fluid hatch that can hold 6 (for example) kinds of fluids and has the capacity (for each fluid, for example) of the corrresponding tier single-fluid output hatch.

• Its GUI could be the same of the single-fluid output hatch and its functionality could be set as one fluid must be emptied to extract the next one.

Looking again at my issue, I'm thinking that another thing that could be more doable (I suppose) is to allow the Blast Alloy Smelter to have up to 3 output hatches (and thus being able to output up to 3 fluids at the same time), so the suggested functionality could be also be accomplished.

You can give it more than one output hatch as is.

I think I have not explained well myself, apologies for that. What I meant by the issue is allowing a given recipe the use of multiple fluid outputs at the same time, for example: iron ore + charcoal + calcite dust = molten iron + CO2 gas + molten slag (so, in this case, you will need 3 fluid output hatches for handling the recipe).

No recipes have outputs like that.
While it can process most EBF recipes, content introduced by Johannes for extended ore roasting is not.

It strictly does metal powders into molten metals, which is how actually metallurgy is done..