Preparing Materials for Societal Applications from Pulp and Paper Mill Black Liquor

Paper, an essential commodity required worldwide, is produced copiously every year in the pulp and paper industries. Globally, an estimated production rate for paper is 55 kg per person per year, which leads to annual black liquor (BL) generation of 170 million tonnes. The BL is generally considered as spent liquor generated during the digestion of lignocellulosic raw material for pulp and papermaking. This BL contains much valuable organic and inorganic material such as lignin, hemicellulose, silica, and lignosulphonates. These components in BL make it suitable for producing various value-added materials for energy and societal applications. Nevertheless, the processing of BL in chemical recovery operations of pulp and paper mills also generates compounds such as dregs, grits and lime mud. These compounds can also be utilized for the production of various value-added products. Materials such as fertilizers, cement, fuels, adhesives, binders, etc., can be obtained from BL and BL-based derivatives via chemical, physical, and biological routes. This chapter aims to present an overview of different materials produced from BL and wastes generated during BL processing for numerous societal applications utilizing various process schemes.