chrome is impossible to make in 0.16 sea block. if you follow the production chain of chrome with THE fNEI mod then there is a liquid called ferrous solution that has only one recipe witch is to be unbarreled. please fix this because chrome is used in lots of end game recipes
Chrome can be made - not sure why FNEI doesn't pick it up but your next step is a Leaching Plant which takes in the ferrous ore dust + crystals + H2SO4 -> ferrous solution