Question, page-4

gafia you are actually wrong you forgot to add in the waste that is created by the sulphuric acid and other chemicals secondly you are not taking into account the amount of water crystallization .when water goes into a mineral it can still be solid gypsum for example is CaSO4.2H20 so any calcium in the ore will be spat out as gypsum thus what was 40 g now weighs 172 g or 4 times as much with perhaps eight times the volume basic chemistry . this of couse changes with different acid if you use hydrochloric acid you get CaCl2 there your 40g now weighs only 111g in the waste pile etc