Phosphoric acid
Phosphate rock dissolved in sulphuric acid: the intermediate behind DAP, MAP and most phosphate fertiliser, and now a feed for LFP batteries.
Commodity chemicals · Acids & alkalis · No. 4
- Single chemical
- Feedstock: Minerals and salts
- about 45 Mt P2O5 a year (2025, indicative; most of the 47.8 Mt of P2O5 used in fertiliser passes through wet-process acid, except single superphosphate and direct rock use)
- 0.5 t CO₂e per t
- HS 280920
Every tonne of phosphate turned into fertiliser acid leaves up to five tonnes of radium-laced gypsum behind.
Chart: Illustration: Phosphoric acid
Where it comes from
Chart: Map of where it comes from
Phosphate rock is dissolved in sulphuric acid, gypsum is filtered off and the acid is boiled down to 52-54% P2O5; about 45 Mt of P2O5 passes through each year.
Three things to know
- Each tonne of P2O5 takes about 3.3 t of rock and 0.9 t of sulphur, so the 2026 sulphur shock flowed straight into acid costs.
- India's quarterly acid contract jumped 25% in one quarter, from $1,360 to $1,700 per tonne of P2O5 in Q3 2026.
- Morocco holds 68% of the world's phosphate reserves, and its OCP dominates the merchant acid trade.
The journey
- 1 Rock miningAbout 250 Mt of phosphate rock
- 2 Sulphur burningSulphuric acid made on site
- 3 DigestionRock dissolved, gypsum filtered off
- 4 ConcentrationEvaporated to 52-54% P2O5
- 5 GranulationAmmoniated into DAP and MAP
- 6 Gypsum stacks4.5-5 t waste per tonne P2O5