Influence of fluidal ashes from lignite on technological properties of slurries based on G-class drilling cements

New generation fly ashes are a produced during coal combustion in fluidized bed furnaces with simultaneous sulphur removal from the gas. This process is held at temperature of about 850 degrees of Celsius. The generated ashes basically differ in their physicochemical properties from traditional silica ashes. Fluidal ashes produced during lignite combustion consist of active puzzolana in the form of dehydrated clayey minerals and active components activating the process of hydration of, e.g. CaO, anhydrite II and CaCO3 ashes. The paper presents the results of laboratory analyses of the influence of ashes coming from the combustion of lignite on technological properties of fresh and set sealing slurries based on drilling cement.