Triple super phosphate fertilizer

The fertilizer industry continues to improve its products to give higher and higher yields of nutrient to plants. Triple Super Phosphate fertilizer is made by first treating phosphate ore with sulfuric acid to make a crude form of phosphoric acid that is often referred to as green acid, because it is colored green and not because it has not been cured or ripened. The green acid is also called wet acid, to differentiate it from phosphoric acid made from elemental phosphorus. Phosphoric acid produced from elemental phosphorus is the purest of acids and it is called furnace acid. 

Rather than treating phosphate ore with sulfuric acid as was done for many years to make Super Phosphate fertilizers. Triple Super Phosphate fertilizer is made by treating phosphate ore with green phosphoric acid. The fertilizer is a crude form of monocalcium orthophosphate, Ca(H2P04)2. An added value of this product is a larger quantity of phosphate contained in a pound of fertilizer and its availability by being highly soluble when it is first applied. As time passes it too becomes insolubilized as mentioned above. All phosphates remain soluble and available as nutrients for a short time on farms or in aquatic environments. 

P2O5 content of candidate acid-phosphates is given in Table 3.1. For comparison, we have also included commercially available phosphoric acid (85% concentrated) and a calcium hydrophosphate fertilizer called triple super phosphate (TSP) in this table. 

Fig. 6.6-30 shows cross sections of broken melt-coated fertilizer granules [B.97]. In this case, the cores of conventionally granulated (by tumble/growth agglomeration. Section 6.6.1) TSP (triple super phosphate) were melt-coated with sulfur to provide an additional nutrient for sulfur-deficient soils and/or obtain a slow-release fertilizer. Fig. 6.6-31 is the flow diagram that is used for this process. The centerpiece of the system is the so-called fluid drum granulator (FDG). 

Location, soii type, texture, sampiing depth and totai phosphorus concentration of controi sites in these studies are given in Table 11.1. Mineral phosphate fertilizer (with single superphosphate, triple super phosphate, calcium apatite, or rock phosphate) unless stated otherwise. Carbon concentrations from Lehmann etal. (2001a). 

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