just a quick post for a noob like me. THERE is no refineing skill and no skill that effects refineing. so dont split your stacks of resources to refine them thinking you will gain skills. took me a min to find that out. i thought a game with this much detail in other area’s would have a refineing skill but i was wrong and it cost me 
only cost you time 
decay cost on the refiner is relative to the size of the stacks you put in it.