Recovery of chemical values from waste gypsum. Final report, December 1989-August 1992

Technical Report · Thu Oct 15 04:00:00 EDT 1992

OSTI ID:6767085

Paisley, M A; Litt, R D

A two-stage, two reactor process is being developed to recover sulfur or sulfuric acid and lime from waste gypsum. Waste gypsum is produced by a variety of industries including chemical, fertilizer and electric utilities. Current environmental regulations are increasing the landfill disposal cost to $30/ton or more depending on specific local conditions. These costs are expected to increase and the quantity of waste gypsum is also expected to increase. The two-stage gypsum recovery process uses two separate fluidized bed reactors to (1) reduce the gypsum to calcium sulfide (CaS) and then (2) roast the sulfide with air producing a SO2-rich gas and regenerated CaO. Fluidization and elutriation problems in the first stage were overcome to achieve up to 85 percent conversion of gypsum to CaS. Reducing gas composition, temperature, and solids residence time were shown to be the primary parameters affecting the reactions. Additional work is needed to achieve even greater conversion and to demonstrate the integrated 2-stage operation. A preliminary economic evaluation indicated a 3-year payback could be achieved for a 1000 ton/day plant. The capital cost was estimated to be $8.5 million. Operating cost savings were based on reduced disposal cost, use/sale of sulfuric acid and use/sale of lime.

• Research Organization: Battelle, Columbus, OH (United States)
• OSTI ID: 6767085
• Report Number(s): PB-93-125011/XAB; CNN: GRI-5089-296-1864
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320305* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Industrial Waste Management
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CALCIUM SULFIDES
CHALCOGENIDES
COST
COST BENEFIT ANALYSIS
DATA
ECONOMIC ANALYSIS
ECONOMICS
ELECTRIC UTILITIES
ELEMENTS
ELUTRIATION
FEASIBILITY STUDIES
FLUIDIZED BED REACTORS
FUEL DISPERSION REACTORS
FUNCTIONAL MODELS
GYPSUM
HOMOGENEOUS REACTORS
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
MANAGEMENT
MATERIALS RECOVERY
MINERALS
NONMETALS
NUMERICAL DATA
OPERATING COST
OXIDES
OXYGEN COMPOUNDS
PILOT PLANTS
PROCESSING
PUBLIC UTILITIES
REACTORS
RECYCLING
SEPARATION PROCESSES
SOLID WASTES
STATISTICAL DATA
SULFATE MINERALS
SULFIDES
SULFUR
SULFUR COMPOUNDS
SULFURIC ACID
WASTE MANAGEMENT
WASTE PROCESSING
WASTES