Phosphoric acid: Emissions

Low carbon, but a 200 Mt-a-year waste problem

What this tab covers The greenhouse-gas footprint per tonne, split by lifecycle phase (feedstock, production, movement, use, end of life), the global total, other environmental impacts, levers and low-carbon routes, India's position, and where the investment opportunity lies. Emission intensity 0.50 t CO2e per t P2O5 range about 0.3-1.0 (wet process); several t for thermal acid on coal power · rock mining and beneficiation, sulphur and acid supply, evaporation and transport; steam from sulphur burners largely covers process heat Global emissions per year 23.0 Mt CO2e per year 2025 · 0.5 t/t x 45 Mt P2O5

Per t P2O5 in merchant-grade wet-process acid, cradle-to-gate. Intensity: Derived from phosphate and sulfur tiles (indicative). Global total: Derived (indicative).

Share of footprint by lifecycle phase

Feedstock 60% Production / process 24% Movement 16%

Footprint by lifecycle phase

Phase	Intensity	Share	Main sources of emissions	Notes	Source
Feedstock	about 0.30 t CO2e per t P2O5	60%	Rock mining, drying and beneficiation; sulphur recovery	About 3.3 t rock per t P2O5	Indicative
Production / process	about 0.12 t CO2e per t P2O5	24%	Grinding, agitation, filtration and evaporation; carbonate in rock releases CO2 on digestion	Integrated sulphur burners supply most steam	Indicative
Movement	about 0.08 t CO2e per t P2O5	16%	Shipping rock, sulphur and acid	Indian acid imports travel 5,000-10,000 km	Indicative
Use	outside the cradle-to-gate total	–	DAP and MAP application	Ammonia in DAP carries far more CO2 than the acid	Phosphate tile
End of life	not applicable	–	Phosphorus run-off	Eutrophication of rivers and coastal waters	Indicative

Other environmental impacts

Phosphogypsum of about 4.5-5 t per t P2O5, about 200 Mt a year (indicative), with radium, fluoride and cadmium; stack failures such as Piney Point, Florida (2021); fluoride emissions; eutrophication from fertiliser run-off.

Levers to cut emissions

Hemi-dihydrate processes that cut evaporation steam and give usable gypsum
Phosphogypsum use in cement, plasterboard and road base
Recovering fluorosilicic acid as a fluorine source (US recovered 45 kt FSA in 2025)
Recovering phosphorus from wastewater and manure (struvite)
Using sulphur-burner power to replace grid electricity

India

India's acid plants import rock and sulphur, so most of the footprint is upstream; CPCB rules promote phosphogypsum use in cement and agriculture. Plant-level emission data were not found.

Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.

Low-carbon routes

Route	Intensity	Cost premium	Status	Source
Purified wet acid instead of thermal acid for LFP and food	about 0.5-1 t CO2e per t P2O5 vs several t for thermal acid on coal power (indicative)	none or negative	standard outside China; growing in China	Indicative
Phosphogypsum valorisation	avoids landfill and natural gypsum mining	depends on purification	pilot and commercial plants in India, Morocco and China (indicative)	Indicative

For a climate investor The climate and resource opportunities are in phosphogypsum use, recovering fluorine and rare earths from phosphate streams, and purified acid for LFP made near Indian cathode plants. These need offtake from cement makers or battery makers and clear radiation and cadmium standards. Coromandel, Paradeep, OCP and Chinese LFP precursor makers are active.