Abstract: A hydroseparator for separating particles based on the differences in settling rates such as for separating fly ash from gypsum includes a substantially cylindrical side wall closed at its bottom end by a floor. A laminar upflow is created through the hydroseparator by adding dilution water to the bottom of the hydroseparator and removing most of the added dilution water from the top of the hydroseparator. The remaining volume of liquid is removed in an underflow. The hydroseparator is divided into at least two sections by a baffle that extends about the interior of the side wall. An inlet is disposed in the center of the hydroseparator slightly above the baffle such that the material added to the hydroseparator to be separated is inserted into the section of the hydroseparator completely surrounded by the baffle.

Abstract: Magnesium hydroxide of high purity, having a fine particle size suitable for use in flame retardants and other high-end uses, is produced by utilizing flue gas desulfurization system process slurry as feedstock; the production process is absent energy-intensive steps as well as high-cost chemical usage.

Abstract: A desulfurization process using magnesium sulfites in a clear solution has the discharge from a wet scrubbing unit passed to a reaction tank. A silica-containing solid particulate material, such as sand, is added to the reaction tank and lime is added to precipitate calcium sulfite solids onto the particulate material. The resulting solids, a calcium sulfite coated, silica containing solid particulate material is readily dewatered and may be used as a cement manufacturing process.