Potential for Post-Production Segregation of Blended Fertilisers

Keywords: fertiliser blending, segregation, tipper-truck, tanker-truck, big bag.

The share of bulk-blends has increased in fertilisation practice, partly because of new demands (for example, sulphur fertiliser) and partly because of lower costs for specific blend formulations. The aim of this study was to analyse three different mineral fertiliser bulk-blends with respect to their segregation in a conical heap, in big bags and in heaps after unloading from tipper-truck and pneumatic tanker-truck. The blends were produced with a sandwich method in a stationary mixing plant with three tanks for each fertiliser component. The fertiliser components are: NPK(S) complex fertiliser: 15% N; 15 % K2O, 15% P2O5 +3% S, granulated, round granules; Calcium Ammonium Nitrate – CAN: 27% N, granulated, round granules; Muriate of Potash – MOP: 60% K2O, compacted, angular grain). Three blends were mixed with different amount of MOP. Blend 1 consisted of 50% CAN and 50% complex fertiliser; Blend 2 consisted of 33% CAN, 33% complex fertiliser and 34% MOP and Blend 3 consisted of 50% CAN and 50% MOP. After mixing 25 tonnes of each blend a cone was poured from which samples were drawn with a sampling spear at 80 cm and 30 cm depths at three levels of the conical heap (bottom, centre, top). Further samples were drawn from big bags and after unloading the blends from a tipper-truck and tanker-truck. A total of 112 fertiliser samples were analysed for N, P2O5, K2O content and for granule size distribution. The results of the nutrient analysis differed substantially between samples taken by the methods described. A higher proportion of MOP with its angular granules in the blend resulted in a segregation within the conical heap. MOP predominated at the top of the conical heap, whereas the round granules of CAN were more inclined to roll down to the bottom. The influence of MOP on segregation is also observed in the analysed unmitigated logistics pathways. Regardless of the blend type, transport in the tipper-truck showed the lowest segregation in comparison to big bags and tanker-trucks.

Gerhard Moitzi, Johannes Pichler, Wolfgang Hofmair, Gerhard Piringer and Andreas Gronauer

Department of Sustainable Agricultural Systems, Division of Agricultural Engineering, University of Natural Resources and Life Sciences (BOKU), Peter Jordan-Strasse 82; A-1190 Vienna, Austria.

Borealis L.A.T. GmbH, St. Peter Strasse 25, A-4021 Linz, Austria.

20 pages, 8 figures, 5 tables, 6 plates, 17 references