Phosphate rock

Phosphate rock is the natural ore from which industry extracts phosphorus for manufacturing fertiliser. It consists chiefly of minerals belonging to the apatite group, with fluorapatite [Ca₁₀(PO₄)₆(F,OH)₂] prevailing in igneous deposits and francolite in sedimentary ones. The latter account for roughly 85% of global reserves and are marked by lower P₂O₅ grades and higher CaO/P₂O₅ ratios, owing to their abundance of calcium-bearing compounds^[1]. Before reaching the market, most ores undergo beneficiation by flotation or other methods designed to raise phosphate content and remove gangue minerals and impurities.

Geological origins and composition

Sedimentary deposits, laid down in ancient marine basins, are plentiful in North Africa, the Middle East, China and the United States. Igneous rocks of volcanic origin occur mainly in Brazil, Canada, Finland, Russia and South Africa. Igneous ores typically display higher P₂O₅ grades, yet remain scarcer on the international market. Naturally occurring impurities — insoluble sands, silica, carbonates — differ markedly from one deposit to another, obliging phosphoric acid plants to adjust their processes continually to shifts in feedstock quality^[2][3].

Industrial uses

Over 95% of phosphate rock mined in the United States goes into wet-process phosphoric acid production, a key intermediate for making ammoniated fertilisers such as DAP and MAP, as well as superphosphoric acid. The remainder feeds elemental phosphorus manufacture, used notably for industrial compounds including the herbicide glyphosate. An alternative route, direct reaction with sulphuric acid, yields single superphosphate (SSP), a lower-analysis fertiliser containing 15–22% P₂O₅ but rich in sulphur and calcium^[4][5].

Market and international trade

World phosphate rock output reached approximately 250 million tonnes in 2025, up 5% from 2024^[4][6]. Proven reserves stand at 73,000 Mt^[6]. Total resources exceed 300 billion tonnes, ruling out any risk of depletion in the near or medium term^[6].

The geography of trade has shifted profoundly: countries endowed with sizeable deposits increasingly prefer to process their ore domestically rather than export it raw. The United States halted all exports in 2003; Russia ships only limited volumes^[6]. This concentration of processing capacity in producing regions — North Africa, the Middle East, China — has caused Western European phosphoric acid capacity to fall by 52% since 1988^[2][7]. In 2004, the European Union sourced 47.5% of its supply from Morocco, 24.3% from Russia, 8.1% from Jordan and 6.2% from Syria^[1][8][9][3].

Quality and impurities

Commercial quality is often expressed in BPL (bone phosphate of lime), a historical measure corresponding to tricalcium phosphate content. An ore grading 72% BPL equates to roughly 33% P₂O₅. Nominal grades range from 29% to 39% P₂O₅ depending on origin^[1][5][10].

All phosphate rocks contain unwanted, sometimes toxic, elements. Sedimentary deposits, which predominate, show higher concentrations of heavy metals — cadmium, chromium, mercury, lead — and radioactive elements — uranium, thorium, radium. Cadmium levels vary enormously: from 0.4 ppm in the igneous Kovdor ore in Russia to 62 ppm in the Tunisian Gafsa deposit, or even up to 600 ppm according to certain analyses^[1][9]. Uranium-238 reaches 1,500 Bq/kg in Florida ore, against merely 30 Bq/kg in Russian Kovdor rock^[11]. These disparities account for the scrutiny devoted to the EU fertiliser regulation and cadmium.

Outlook

World production capacity expressed as P₂O₅ is expected to rise from 63.7 Mt in 2025 to 71.7 Mt by 2029, with expansion projects under way in Brazil, Kazakhstan, Mexico, Morocco and Russia^[4]. Global fertiliser P₂O₅ consumption, estimated at 47.8 Mt in 2025, could reach 51.5 Mt in 2029, with Asia and South America as the main growth engines^[4]. In the United States, where apparent consumption fell by 7% in 2025, a new deposit has been approved in Idaho to replace an existing mine within the coming decade^[4][6]. On 7 November 2025, phosphate rock was added to the US critical minerals list, alongside boron, metallurgical coal and uranium^[6].