Phosphate Rock Grinding Project for Fertilizer Production (5 TPH, 320 Mesh)​

Phosphate Rock Grinding Project for Fertilizer Production (5 TPH, 320 Mesh)​
 

Phosphate rock (primarily Ca₃(PO₄)₂) is the primary raw material for phosphate fertilizers, essential for global food security. This article details a phosphate rock grinding project in Florida, USA—a major phosphate-producing region—designed to supply a nearby fertilizer plant with 320-mesh phosphate rock powder at 5 TPH. The project focuses on maximizing phosphorus (P₂O₅) availability, a key factor in producing high-efficiency fertilizers like diammonium phosphate (DAP).​
 

Project Rationale and Fertilizer Industry Requirements​

Phosphate fertilizers require phosphate rock with high P₂O₅ content (typically >30%) and fine particle size—finer powder increases the surface area available for reaction with sulfuric acid (H₂SO₄) during fertilizer production. The fertilizer plant specified 320-mesh (45 μm) fineness because it balances reaction efficiency (≥95% P₂O₅ conversion) and grinding costs—finer powder (≥350 mesh) would increase energy use without significant gains in conversion. The 5 TPH capacity matches the plant’s daily DAP production (120 tons per day, requiring 120 tons of phosphate rock powder).​
 

Raw Material and Pretreatment​

Raw phosphate rock is sourced from the Bone Valley Formation in Florida, with a P₂O₅ content of 32-34% and a moisture content of 8-10% (higher than other regions due to Florida’s humid climate). Pretreatment is critical to remove moisture and impurities: (1) Drying: Raw phosphate rock is fed into a rotary dryer (heated by natural gas) at 120°C, reducing moisture to <2%—high moisture causes agglomeration in the grinding mill;

(2) Crushing: Dried phosphate rock (initial size 100-200mm) is crushed to 10-15mm using a jaw crusher (primary) and a cone crusher (secondary); (3) Screening: A vibrating screen removes oversize particles (>15mm) and fine dust (<1mm) (dust is recycled to the dryer to avoid waste).​