It is impossible to obtain platinum dust. For Tech Reborn mod Platinum dust is very important material in late game and you need it to create hot platinum and later platinum plates. But the only way to get platinum is to find Iridium ore which is very rare. I already mined few chunks and got 0 Iridium ore. You should bring back recipe from Tech Reborn where you can get platinum dust by grinding Sheldonite ore in industrial grinder. Now we get raw platinum and it is useless if we can't even smelt it.

This is intended, some other changes may be done in the future, but the overall method for making platinum will not change any time soon.

What is the intended way of acquiring platinum plates? There is really no way to progress TR any further without having the matter fabricator for uu-matter.

There are two ways to get platinum. It's either do modern industrialization stuff by crafting electric quarry and titanium drill to get indium ore or trade with oceanographer and by trading many heart of the sea and put them in industrial grinder (TR) and you get small pile of platinum dust then craft platinum dust.

Sounds a little counterintuitive but thanks a lot for your help :)
Would like to reintroduce the sheldonite ore variant.