Auxiliary Machines FAQ

Two things, in order. First, screen the pellets after drying to separate oversize and undersize from the saleable fraction — oversize is crushed and returned to the granulator, fines return with fresh binder. Second, pass the screened product through a polishing machine, which rotates the pellets at high speed so that their surfaces are rounded and their size distribution tightens. Screening alone fixes most of the problem; polishing is what makes the product look manufactured.

Use a coating machine. It applies a powder or liquid film to the pellet surface, which prevents pellets from sticking to each other during storage and transport and reduces dust. Coatings can also carry colour and additional nutrients. Caking has three causes — residual moisture above 14%, product temperature above 40 °C at bagging, and inadequate coating — and all three should be addressed together.

No. The granulator forms the pellet; the polishing machine improves its shape and surface. Pellets from a stirring-tooth or rotary drum churning granulator are usually round enough to sell without polishing. Pellets from a process that leaves them irregular, or products destined for retail horticultural markets where appearance matters, benefit from polishing.

There is no special requirement on the bag material. Our standard packing units use a bag-sewing machine rather than a heat-melt closure, so they accept woven polypropylene, paper sacks and lined bags equally well. Where moisture protection matters — typically for powder fertilizer in humid climates — a polyethylene liner inside a woven bag is the practical combination.

No, coating applies to pellets. On a powder line, caking is controlled instead by drying the product to a low moisture content and adding an anti-caking agent at 0.5–2% during mixing. The two approaches solve the same problem in the form appropriate to the product.

Beyond polishing, coating and packing: conveying between every pair of machines, a buffer bin ahead of the granulator and the dryer, dust collection at the crusher, screener, cooler and packing station, and a control panel. On larger lines, automatic batching and a palletiser are the auxiliary systems that reduce labour most.