Beneficial uses of pulp and paper power boiler ash residues

摘要: Ash residuals generated from recovery and power boilers combusting wood residues, sludges, or auxiliary fuels constitute a major fraction of the solid residues produced by pulp paper mills. Generation rates in Canada, likely elsewhere, for ashes different types have increased substantially since mid-1990s. Landfilling is primary disposal method, but there are many potential beneficial applications these ashes. Large-scale opportunities include land application construction. Smaller-scale exist within both wastewater treatment systems papermaking process. Ashes wood-fired generally more suitable than those coal combustion, as they contain fewer metals at lower concentrations (except cadmium). The benefit arises neutralizing properties ashes, provide alkalinity to soil. Compared fly bottom higher bulk density, carbon content few, if any, dioxins furans. Land salt-laden hog coastal mills regulated However, steps can be taken minimize generation such chlorinated organics, making application. Application:The large increasing volume ash Canadian motivating search options other landfilling. Careful attention chemistry boiler operation maximize applications. A number promising new uses residual been identified, producers starting view their valuable product rather waste problem.