Farewell to Filters: the Recycle of Clarifier Mud to the Diffuser

suspended solids % mixed juice levels encountered at diffuser A cane diffuser is a fairly efficient filter, retaining within the bagasse bed much of the suspended material that would otherwise pass into the draft juice. It was decided to investigate the possibility of utilising this filtration capability further by recycling the mud (underflow) from the juice clarification station to the diffuser(s). The solids in the mud would then be carried in the bagasse to the boilers, where the combustible portion would be incinerated and non-combustible material would become boiler ash. Maidstone mill was selected for a trial, as it has two diffusers and uses two clarifiers, facilitating comparison. A two-week trial was carried out in which the mud from one of the clarifiers was recycled on to the bed of one of the diffusers. This was followed by a one-week trial in which all of the clarifier mud was recycled to one of the diffusers, during which period no filtercake was produced bv the factorv. ~esults-of these trials are discussid, and effeEts on diffuser operation, extraction, sucrose degradation, and ash levels in bagasse and juice are examined. The practice of mud recycle offers the possibility of eliminating completely the need for a filtration station and its ancillaries (including bagacillo systems and filtercake conveying) in an ordinary raw sugar diffuser factory.