Location
Grand Rapids, Michigan
Start Date
14-5-2024 1:00 PM
End Date
14-5-2024 1:30 PM
Description
The focus of this study was to manufacture sintered lightweight aggregates (LWA) using unrecycled landfill condition waste coal ash (LC-WCA) that has been exposed to a harsh weathering and storage environment for 15-20 years. WCA under field conditions typically consists of an intricate blend of fly ash, bottom ash, boiler slag, flue gas desulfurization, cenosphere, sand, rocks, shells, twigs, and various land minerals. This complicated raw material blend obtained from a Pennsylvania landfill underwent characterization to understand its physical and chemical composition. Microscopy revealed LC-WCA composition consisted of 9% field debris (size ≥600 μm), 43% bottom ash (size 600-75 μm), and 48% fly ash (size ≤75 μm). Sintering at 1100ºC with 2% NaOH yielded LC-WCA- LWA minimum required slag content of 35% and viscosity above 100 pa.s for successful LC-WCA-LWA production. The study established that coating material was necessary to control aggregate size during pelletization and prevent agglomeration during sintering. Optical microscopy indicated efficient core-shell development with shell thickness at 10- 15% of core diameter. The LC-WCA-LWA unit weight and specific gravity were within the EN13055 standard limits for LWA classification. Spoon drop tests confirmed that 2% NaOH achieved LC-WCA-LWA with enough structural integrity for concrete mixing. This study validates the effective conversion of LC-WCA into successful LWA.
Document Type
Presentation
Paper_A Practical Approach to Manufacturing Sintered Lightweight Aggregates from Unrecycled Waste Coal Ash
Grand Rapids, Michigan
The focus of this study was to manufacture sintered lightweight aggregates (LWA) using unrecycled landfill condition waste coal ash (LC-WCA) that has been exposed to a harsh weathering and storage environment for 15-20 years. WCA under field conditions typically consists of an intricate blend of fly ash, bottom ash, boiler slag, flue gas desulfurization, cenosphere, sand, rocks, shells, twigs, and various land minerals. This complicated raw material blend obtained from a Pennsylvania landfill underwent characterization to understand its physical and chemical composition. Microscopy revealed LC-WCA composition consisted of 9% field debris (size ≥600 μm), 43% bottom ash (size 600-75 μm), and 48% fly ash (size ≤75 μm). Sintering at 1100ºC with 2% NaOH yielded LC-WCA- LWA minimum required slag content of 35% and viscosity above 100 pa.s for successful LC-WCA-LWA production. The study established that coating material was necessary to control aggregate size during pelletization and prevent agglomeration during sintering. Optical microscopy indicated efficient core-shell development with shell thickness at 10- 15% of core diameter. The LC-WCA-LWA unit weight and specific gravity were within the EN13055 standard limits for LWA classification. Spoon drop tests confirmed that 2% NaOH achieved LC-WCA-LWA with enough structural integrity for concrete mixing. This study validates the effective conversion of LC-WCA into successful LWA.
