Production of ammonium sulfate fertilizer from FGD waste liquors. Second quarterly technical report, April--June 1995

摘要

In June of this quarter, two 50 gallon drums of ferrous EDTA scrubbing liquor were supplied by Dravo Lime Company (Fort Miami, OH plant) for continuing investigation of the precipitation of N-S containing crystals in the DDO (Double-Draw-Off crystallizer) configuration. In order to further study the influence of design variables on the size of Nitrogen-Sulfur (N-S) containing product crystals, another DDO run was carried out at a higher DDO ratio. The new liquor was found to have a much lower pH (approximately 4.5) compared to the previous supply (approximately 6.8). The liquor was also found to contain higher amounts of sodium and sulfur. Hydrolysis experiments were conducted in a one liter jacketed glass vessel, equipped with a temperature controller, using 1 M H2SO4 at 70 C and 80 C under atmospheric pressure. The purpose of these hydrolysis experiments was to evaluate kinetic information and to generate enough hydrolyzed liquor to produce NH3 gas. The NH3 gas is then used to neutralize the diluted sulfuric acid solution and precipitate pure ammonium sulfate crystals.