MANUFACTURE OF AMMONIUM SULFATE FERTILIZER FROM FGD-GYPSUM

摘要

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, from gypsum produced as part of lime/limestone flue gas desulfurization (FGD) processes. Millions of tons of FGD-gypsum by-product will be produced in this decade. In this study, a literature review and bench-scale experiments were conducted to obtain process data for the production of marketable products from FGD-gypsum and to help evaluate technical and economic feasibility of the process. FGD-gypsum produced at the Abbott power plant in Champaign, IL was used as a raw material. The scrubber, a Chiyoda Thoroughbred 121 FGD, produced a filter cake product contains 98.36% gypsum (CaSO_4·2H_2O), and less than 0.01% calcium sulfite (CaSO_3). Conversion of FGD-gypsum to ammonium sulfate were tested at temperatures between 60 to 70℃ for a duration of five to six hours. The results of a literature review and preliminary bench-scale experiments are presented in this paper.