ARBOK-PHOSACID: Phosphoric Acid for LFP Batteries from Fertilizer-Plant Waste

Lithium iron phosphate (LFP) cathodes are made from an iron-phosphate precursor, and the precursor is made from purified, battery-grade phosphoric acid. About 70% of that acid is controlled by one country, and its price has recently risen by almost a third. The raw material is not scarce: phosphate rock is mined in many countries, and every phosphate fertilizer plant carries ponds of acidic effluent and stacks of phosphogypsum that still hold phosphoric acid. What is missing is a purification step that works on this dirty feed without a chain of reagents. We describe ARBOK-PHOSACID, a containerized deep-vacuum phase-change separation of liquid acidic phosphate waste at ambient temperature, with no membranes, no filters and no reagents. One module processes 200 t of effluent per day at 2–4 kWh per tonne and leaves under 0.2% inert residue. Radium, uranium and thorium are removed up to 99.5% and stabilized in a solid salt matrix. At a deliberately low acid price of 900 USD per tonne, one container yields about 1,800 t of acid and 1.6 million USD a year; the Florida stacks alone support about 700 containers and about 1.4 billion USD a year including avoided medical costs, and halting the annual growth of the world's stacks needs about 1,400 containers and about 2.2 billion USD a year in acid. The unit is at TRL 7. Keywords: phosphoric acid, lithium iron phosphate, LFP cathode, phosphogypsum, fertilizer plant effluent, deep-vacuum separation, critical materials, supply chain