what could this be?

[Barbamaus]

Any clue what this is?

[vatas]

Maybe current kilns will be harder to make and that will be the new "primitive" only clay required -version?

I dunno, that's the only thing I can come up with.

Or maybe it's a primitive oven instead?

[bumfrog]

in the trailer a hearthling appears to be pouring molten metal into it, so it’s almost certainly some kind of new crucible tied to the metal industry/spiraling changes

[Barbamaus]

in the trailer a hearthling appears to be pouring molten metal into it, so it’s almost certainly some kind of new crucible tied to the metal industry/spiraling changes

I watched the trailer again to see what you were talking about, and I still don't see it. I do see it put somewhere close to the smelter though.
The fact that everything is so well placed in that village, except for that item, makes me wonder if you can lift it...

[Odynak]

It is a bathtub. Not installed yet.

[bumfrog]

in the trailer a hearthling appears to be pouring molten metal into it, so it’s almost certainly some kind of new crucible tied to the metal industry/spiraling changes

I watched the trailer again to see what you were talking about, and I still don't see it. I do see it put somewhere close to the smelter though.

It’s at 0:39 in the trailer on youtube. Sorry for the low-res image, look at the video yourself for a better version. Definitely a dude messing with molten metal

[The_Lich_King]

in the trailer a hearthling appears to be pouring molten metal into it, so it’s almost certainly some kind of new crucible tied to the metal industry/spiraling changes

I watched the trailer again to see what you were talking about, and I still don't see it. I do see it put somewhere close to the smelter though.

It’s at 0:39 in the trailer on youtube. Sorry for the low-res image, look at the video yourself for a better version. Definitely a dude messing with molten metal

It might be the new first stage for metalworking. Some ceramic kilns were one time use, and would completely encompass the ore being smelted. You would then break the kiln and harvest the metal and slag inside.

This might be an example of a single use smelter.

[Barbamaus]

I watched it over and over, and I do see some molten stuff being poured into it; I'm starting to think it's something related to either glassmaking or some kind of mould.

In the trailer we're shown three stages of the same village:

Stage 1: nothing interesting

Stage 2: we see a kiln, an oven, and a stack furnace. That means this new thing doesn't replace any of those, nor comes before it. So it's unlikely to be yet another kind of smelter.

Stage 3: Stack furnace is gone, replaced by the bigger smelter. We see the new item appear, with something being poured into it (same textures as molten metal or molten glass). I find it interesting that we don't see a crucible though, which is what makes me wonder if this is some sort of new crucible. We also don't see any advanced metal industry structures, like finery forge or the steel making thingy, but I doubt it's replacing one of those.