Every rock phosphate quote leads with a percentage — but that single number hides two separate measurements that matter for different reasons. Here's what's actually behind the grade.
P₂O₅ (phosphorus pentoxide) is the standard measure of usable phosphorus in rock phosphate. It's reported two ways: total P₂O₅ (all phosphorus present) and citric-soluble P₂O₅ (the reactive portion, roughly indicating how readily available it is for processing).
| Grade | Total P₂O₅ | Citric-Soluble P₂O₅ | Moisture |
|---|---|---|---|
| Grade B (26%) | 26.86% | 8.86% | 0.95% – 1% |
| Grade A (28%) | 28.66% | 11.05% | 0.91% – 1% |
| High-Grade (30%) | 30% | 12.50% – 13.50% | 0.85% – 1% |
A higher total P₂O₅ number looks better on paper, but the citric-soluble figure often determines processing efficiency. Serious buyers ask for both figures, not just the headline percentage.
Generally, higher-grade rock phosphate (28%+) is preferred for phosphoric acid production and higher-reactivity fertilizer processes. Mid-grade material (26%) is commonly used in Single Super Phosphate (SSP) production.
Available as raw lumps or fine powder (standard grind: mesh size 130–150). Powder suits direct acid digestion; lumps suit buyers doing their own crushing on-site.
DAP typically starts from phosphoric acid, generally produced more efficiently from higher-grade rock phosphate. Our 28% and 30% grades suit this route.
Grade blending is possible depending on order volume — mention your target specification when requesting a quote.