Boiler ash utilization in the Canadian pulp and paper industry

Keywords Ash utilization; Canadian pulp paper mills; Biomass boiler ash; Fly ash; Bottom ash; Ash application Highlights * General ash characterization is not enough to find useful applications of ash. * Ash use in the liming agent requires different properties than ash use in concrete. * Ash must be characterized according to its application requirements. * PPM ash can mainly be used for concrete, ag lands, liming agent, and forest roads. Abstract Pulp and paper mill biomass boilers generate large quantities of ash in Canada with British Columbia (BC) being the highest ash generating province followed closely by Quebec. Generally, the generated ash is landfilled, particularly in BC, with only a small amount being used beneficially. It is anticipated that the difficulty associated with the management of ash will worsen over time as the industry increases its reliance on green fuel. Thus, there is a strong need to identify beneficial uses of pulp and paper boiler ash for the sake of environmental and economic sustainability. The purpose of this report is to provide the first step in this direction, a review of proposed or implemented uses for coal and hog (or wood) ash around the world. Considering both the properties of the ash and local opportunities, this could be the first step toward screening the applications that may apply to individual mills. Several large-scale practices use ash, such as land application (as a nutrient source or as a liming agent), use in the construction industry (as a replacement for cement or as a fill material), and reclamation of mine sites and stabilization of unpaved forest roads. In some cases, relatively small-scale applications have been used which included uses such as a compost component, agent for pH adjustment of liquid streams and slurries, blasting abrasive, and source of quartz for glass manufacturing to name a few. It is important to note that the chemical nature of both fly and bottom ashes can be quite variable due to the type of wood residues combusted as well as combustion equipment used and must be considered in identifying beneficial applications. Abbreviations AB, Alberta; ASTM, American Society for Testing and Materials; BC, British Columbia; CCE, Calcium Carbonate Equivalents; CCME, Canadian Council of Ministers of the Environment; CFIA, Canadian Food Inspection Agency; GHG, Greenhouse Gas; ITE, Inorganic Trace Element; LOI, Loss on Ignition; MSW, Municipal Solid Waste; NS, Nova Scotia; ON, Ontario; QC, Quebec; TNV, Total Neutralizing Value; XRF, X-ray Fluorescence Author Affiliation: (a) FPInnovations, Pointe-Claire, QC, H9R 3J9, Canada (b) FPInnovations, Vancouver, BC, V6T 1Z4, Canada * Corresponding author. Article History: Received 8 February 2022; Revised 29 June 2022; Accepted 9 July 2022 Byline: Allan Elliott [allan.elliott@fpinnovations.ca] (a), Talat Mahmood [talat.mahmood@fpinnovations.ca] (a), Abu Kamal [kamal.abu@gmail.com] (b,*)