An investigation of drum granulation of biochar powder

• Biochar granules were made through wet drum granulation.
• Drum speed and binder concentration and volume affected granules.
• Granules can provide easy and effective application to soils.

Biochar is a fine powder that is difficult to handle and would be blown away if applied to soils without modifications. Wet drum granulation of biochar using binder solutions of hydroxypropyl methylcellulose was investigated to create a form that would be easier to handle and apply effectively to the soil. The biochar granules were free flowing and approximately spherical with a significant yield between a size range of 1 to 4 mm. The binder concentration, total binder solution volume and drum rotational speed all affected the yield of granules within this size range. The drum rotational speed and binder concentration affected the granule strength; biochar granules were resistant to attrition and showed a crushing strength of 0.15 to 0.50 MPa. The results demonstrated that biochar can be granulated using wet drum granulation. Further research is required to further refine the granulation parameters to produce granules with comparable characteristics to fertilizers to ensure that the granules could be effectively applied to soils using existing infrastructure and techniques.

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