I think Uranium processing is quite debalanced with this mod right now.

Well, yes and i don't see how i could ever rly balance it ...

For 10 uranium-ore you (may) get:
1 uranium-238 with a probability of 99.3% (0.993)
1 uranium-235 with a probability of 00.7% (0.007)

So in average:
for 1 U-238 -> 1000 to 993 or 1.007 for 1
for 1 U-235 -> 1000 to 7 or 142.857 for 1

ore melts into 20 fluid we get:
201.409 for 1 U-238
285.714 for 1 U-235

Since we essentially creating U-235 directly from ore without a byproducts _(U-238) i multiplied it with 100 to compensate because in Vanilla it takes about 100 ore to get 1 U-235 (a bit more actually but who rly cares at this point).
Therefore 28571.428/2 (divided by 2 because 28k feels like to much) is a reasonable amount. At least i think so.

What do you think would fit better?

Vanilla:
10 uranium ore -> 1 of U-238 (99.3% ) or U-235 (0.07%) (ratio 10:1)

Molten metals:
60 uranium ore -> 120 molten uranium (ratio 60:120 = 1:2)
200 molten uranium -> 1 of U-238 (99.3% ) or U-235 (0.07%) (ratio 200:1)

The conclusion is that I need to smelt 10 times more uranium to get the same amount of output.
I think it should be 20 molten uranium -> 1 of U-238....

Oh now i see what you mean! The numbers are wrong somehow o.0
Ill fix that.

Maybe if adding something like a catalysator for direct casting U-235 will make it a bit more balanced?
Something like a coolant or control rods.

Just dividing by 10 the requirements of molten uranium should be balanced, on the one to generate 1 U-238 and the one that requires a lot to generate 1 U-235.

I read the amount of ore needed and the amount of the result from the recipes so even if mods alter them i end up with the correct value.
Both are then multiplied by 2 for the ingredient and 40 for the result, so i end up with eg: 2 iron-ore -> 40 molten-iron-ore.
These amounts are then multiplied by 3 which was fine for iron and copper etc but resulted in 60:120 for Uranium (10x2x3 and 1x40x3)

This will be fixed at some point but for now i set the required amount to 200/2000

You can get the preview for 0.1.5 here:
https://github.com/Yokmp/Molten_Metals
Just click code and download zip.
you then just unzip the folder into your mods folder and rename Molten_Metals-master to
Molten_Metals_0.1.5

Just remember to delete it when the new version on the mod portal is released (should happen over the next days)