TRIPLE SUPERPHOSPHATE

GTSP

Granular Triple Superphosphate

 

Triple Superphosphate is a high analysis product of the reaction between phosphate rock and phosphoric acid, containing 45 - 48% available phosphate (AP). Triple superphosphate plants are mainly large units operating as a part of chemical complexes, located near the source of phosphate rock. Therefore, a large percentage of the world production is produced in Florida and North Carolina, close to this major phosphate mining area.

While there are variations of processess used, the two major routes are the so-called "solid" and "slurry or quick-cure" processes with both routes together with individual modifications being employed by the producers in Florida and North Carolina. The properties of the triple superphosphate depend upon the specific process used and on the granular or non-granular nature of the product. The chemical and physical characteristics of the material depend on the nature of the phosphate rock, including composition(72-75 BPL) and degree of fineness (70-85% minus 200 mesh), the concentration of the phosphoric acid and the method of manufacturing.

Note: BPL = Bone Phosphate of Lime = 2.1852 x P2O5

In the production of run-of-pile or non-granular triple superphosphate, phosphate rock and concentrated phosphoric acid (50-54% P2O5) are brought together into a mixer which discharges directly into a continuously moving den. A very dense slurry is produced which solidifies readily into a porous, honeycomb-like mass. It is carried to a rotating cutter where it is chopped into particles and then conveyed to the storage area for pile curing where the reaction continues for several weeks.

After curing, the material is reclaimed with power equipment and shipped as run-of-pile triple superphosphate or granulated by treatment with water and steam in a rotary drum, followed by drying and screening and shipped as granular triple superphosphate. Note: Granular Triple Superphosphate is the predomintate product being produced today.

In the "slurry" granulation process, the phosphate rock is reacted with relatively weak phosphoric acid (32-40% P2O5). The resulting slurry is mixed with a large quantity of dried, recycled fine granules which are coated with the slurry, thus producing the desired granule size. The coated granules are dried and screened and the product size material is withdrawn to storage, the remainder being recycled to the process. The product is ready for shipment without any further curing required.

Triple superphospate is shipped by rail and is exported through the Florida and North Carolina ports for water shipment. It is used in the formulation of high analysis grade fertilizers and also applied directly to the soil as a single nutrient material.