Steel converter slag as a raw material for precipitation of pure calcium carbonate

In this work we study the possibility of utilizing steel converter slag, a byproduct of steel manufacturing, for production of pure calcium carbonate. The dissolution of calcium from steel converter slag by using acetic acid as a solvent and the precipitation of pure calcium carbonate from the resulting solution were experimentally investigated. It was found that, while strong solutions of acetic acid dissolve most of the calcium from the slag, weak acetic acid solutions dissolve calcium selectively. Precipitation of any substantial amount of calcium carbonate was found to require the addition of sodium hydroxide. Calcium conversion from the solution into the precipitate was as high as 86%, and the purity of the precipitate was over 99%. The calcium carbonate particles produced at low temperatures were found to have rhombohedral particle shapes, a very high brightness (98.7%), and a small particle size (mean value of 0.6 mu m).