The paper discusses current bench- and pilot-plant advances in preparation of ADVAnced siliCATE (ADVACATE) calcium silicate sorbents for flue gas desulfurization. It also discusses current bench- and pilot-plant advances in sorbent preparation. Fly ash was ground in a laboratory-scale grinder prior to slurrying in order to decrease the slurrying time needed for the sorbent to be reactive with SO2. Reactivity of ADVACATE sorbents with SO2 in the bench-scale reactor correlated with their surface area. ADVACATE sorbents produced with ground fly ash were evaluated in the 1.42 cu m/min pilot plant, providing 2 s duct residence time. ADVACATE sorbent was produced by slurrying ground fly ash (4.3 micrometer median particle size) with Ca(OH)2 at a weight ratio of 3:1 at 90 C for 3 h to yield solids with 30 wt % of initial free moisture. When the sorbent was injected into the duct with 1500 ppm SO2 and at 11 C approach to saturation, the measured SO2 removal was about 60% at a Ca/S stoichiometric ratio of 2.0. Previously, when ADVACATE sorbent was produced at 90 C and at the same fly-ash-to-Ca(OH)2 weight ratio using unground fly ash, removal under the same conditions in the duct was about 50% following 12 h slurrying. The report gives results of pilot-scale recycle tests at the recycle ratio of 2.0. Finally, the report discusses EPA's plans to commercialize ADVACATE.