Open AccessBUILDING MATERIALS MADE FROM FLUE GAS DESULFURIZATION BY-PRODUCTS
Author(s) -
Michael W. Grutzeck,
Maria DiCola,
Paul Brenner
Publication year - 2006
Language(s) - English
Resource type - Reports
DOI - 10.2172/881574
Subject(s) - flue gas desulfurization , flue gas , gypsum , waste management , fly ash , lime , slurry , calcium carbonate , calcium hydroxide , coal , raw material , data scrubbing , fossil fuel , environmental science , chemistry , materials science , metallurgy , engineering , chemical engineering , environmental engineering , composite material , organic chemistry
Flue gas desulphurization (FGD) materials are produced in abundant quantities by coal burning utilities. Due to environmental restrains, flue gases must be ''cleaned'' prior to release to the atmosphere. They are two general methods to ''scrub'' flue gas: wet and dry. The choice of scrubbing material is often defined by the type of coal being burned, i.e. its composition. Scrubbing is traditionally carried out using a slurry of calcium containing material (slaked lime or calcium carbonate) that is made to contact exiting flue gas as either a spay injected into the gas or in a bubble tower. The calcium combined with the SO{sub 2} in the gas to form insoluble precipitates. Some plants have been using dry injection of these same materials or their own Class C fly ash to scrub. In either case the end product contains primarily hannebachite (CaSO{sub 3} {center_dot} 1/2H{sub 2}O) with smaller amounts of gypsum (CaSO{sub 4} {center_dot} 2H{sub 2}O). These materials have little commercial use. Experiments were carried out that were meant to explore the feasibility of using blends of hannebachite and fly ash mixed with concentrated sodium hydroxide to make masonry products. The results suggest that some of these mixtures could be used in place of conventional Portland cement based products such as retaining wall bricks and pavers