Manufacture of ammonium sulfate fertilizer from FGD-gypsum. @article{osti_460120, title = {Manufacture of ammonium sulfate fertilizer from FGD-gypsum}, author = {Chou, M I.M. and Bruinius, J A and Li, Y C}, abstractNote = {The goal of this study is to assess the technical and economic feasibility of producing marketable products, namely fertilizer-grade ammonium sulfate and calcium carbonate ...