Lignin micro- and nano-particles (LMNPs) synthesized from side-streams of pulp and paper and biorefinery operations have been proposed for the generation of new, high-value materials. As sustainable alternatives to particles of synthetic or mineral origins, LMNPs viability depends on scale-up, manufacturing cost and applications. By using experimental data as primary source of information, along with industrial expertise, we analyze dry and spherical LMNPs obtained by our recently reported aerosol/atomization method. First, a preliminary evaluation towards the commercial production of LMNP from industrial lignin precursors is presented. Following, we evaluate potential LMNP applications from a financial perspective. Mass and energy balances, operating costs and capital investment are estimated and discussed in view of LMNP scalability prospects. The main potential market segments identified (from a financial perspective) include solid foams, emulsion stabilizers, chelating agents, and UV protection. Our technical, cost, financial and market assessment represent the basis for R&D planning and efforts to lower the risk related to expected industrialization efforts in this area. Manufacturing costs were estimated between 870 and 1,170 USD/t; also, minimum selling prices varied from 1,240 and 1,560 USD/t, depending on raw materials used. Sensitivity analysis indicated that manufacturing costs can be as low as 600 USD/t, depending on the process conditions considered. Finally, based on financial assessment, potential applications were identified, such as emulsion stabilizers, UV protection products, chelating agents and polymer nanofillers.

Lignin is an abundant, renewable, and relatively cheap biobased feedstock that has potential in energy, chemicals, and materials. Kraft lignin, more specifically, has been used for more than 100 years as a self-sustaining energy feedstock for industry after which it has finally reached more widespread commercial appeal. Unfortunately, hardwood kraft lignin (HWKL) has been neglected over these years when compared to softwood kraft lignin (SWKL). Therefore, the present work summarizes and critically reviews the research and development (R&D) dealing specifically with HWKL. It will also cover methods for HWKL extraction from black liquor, as well as its structure, properties, fractionation, and modification. Finally, it will reveal several interesting opportunities for HWKL that include dispersants, adsorbents, antioxidants, aromatic compounds (chemicals), and additives in briquettes, pellets, hydrogels, carbon fibers and polymer blends and composites. HWKL shows great potential for all these applications, however more R&D is needed to make its utilization economically feasible and reach the levels in the commercial lignin market commensurate with SWKL. The motivation for this critical review is to galvanize further studies, especially increased understandings in the field of HWKL, and hence amplify much greater utilization.