Since calcium oxalate is 3000 times less soluble than calcium sulfate, would it be possible to concentrate sulfuric acid from let's say 50% solution using following steps? :
- adding calcium carbonate to cold dilute H2SO4
- filtering off resulting CaSO4
- mixing CaSO4 with oxalic acid in 1:1 molar ratio
- adding just enough water to submerge the solids
- vaccum filtering off the now concentrated (hopefully) H2SO4
My reasoning behind this is that even though at any given time theres only a small amount of CaSO4 dissolved, the reaction producing sulfuric acid would eventually go to completion with high yield due to it's the massive kinetic favourability. The only problem I see is that the amount of water needed would limit the final concentration. Would adding merely enough water to wet all the solid still work, improving the final concentration?