Agglomeration of Biochar for Agronomic Use.

Use of biochar, a carbonaceous co-product from fast pyrolysis of biomass for bioenergy production is view as a beneficial soil amendment. As fast pyrolysis feed material is finely ground to assure efficient extraction of energy, the resulting biochar is a light weight, fine textured, dusty-type material. Surface application of biochar in such form result in material losses as it is carried off site by wind and water, diminishing its agronomic impact while polluting air and water resources. Using a lab-scale disc agglomeration system we evaluate the use of several binders in agglomerating fast-pyrolysis biochar for its use as soil amendment. In addition, selected additives were used to enhance the ball-shaped pellets physical properties and agronomic value. Initial criteria included creation of a stable ball that will sink in water and will not disintegrate immediately upon immersing. Pellets were evaluated for shape, size, uniformity, and tested for additional physical properties (drop strength, specific density, and attrition). Best performing ball pellets were further tested for nutrient content and availability, and liming potential. The results of this study showed that use of selected binders and additives can form ball pellets that are unlikely to pose environmental concerns when surface applied to soil. Furthermore, incorporation of selected additives improved ball pellet physical properties, liming potential, and nutrients availability.