Several metal dusts (Brass, Electrum, Invar, etc...) cannot be smelted into ingots without the use of TiC or IE's Arc Furnace.
Similarly, metal blocks of the same type (made via TiC smeltery, since you can't craft them) cannot be crafted into ingots.
Additionally, Ashes can be Electrolyzed for Carbon Fiber Cells, instead of Carbon Cells. Carbon Cells can be made into Carbon Fiber, but Carbon Fiber Cells can't be used for anything.