Iodine: Extraction

How a desert and gas fields yield iodine

Iodine is never mined on its own. Most comes from three settings: the caliche nitrate deposits of Chile's Atacama Desert, brines pumped with natural gas and oil in Japan, and deep iodine-rich brines in northwestern Oklahoma. In Chile, crushed caliche is heap-leached and iodine is recovered alongside nitrates. Brine producers oxidise the dissolved iodide, then blow out or absorb the iodine and crystallise it. Seaweed ash was a major source before 1959. The oceans still hold about 90 billion tons, but at only 0.06 ppm.

Iodine is never mined on its own. It is a co-product of nitrate mining in Chile, a by-product of natural gas and brine production in Japan, the US, Turkmenistan and Iran, or recovered from waste streams. Chile's caliche route supplies about two-thirds of non-US output; it is cheap at scale because the same leach solutions also yield nitrates. Brine producers depend on the volume of gas or brine they handle, so their supply is inelastic.

Methods compared

How each method works

Nitrate-iodine caliche from the Atacama is blasted and loaded from shallow pits, stacked on lined heaps and irrigated with water or recycled solution. The iodate-rich leachate goes to plants where it is reduced to iodine, which is filtered, melted and prilled. The same solutions yield sodium and potassium nitrate after solar evaporation. SQM's Nueva Victoria is the main example.

Large, low-cost, scalable supply; dependent on Chilean water and permits and on nitrate markets.

Brine produced with natural gas in Chiba prefecture holds high iodine concentrations. Iodide is oxidised and recovered by blowing-out or ion exchange, and the depleted brine is reinjected. Output is capped by how much gas and brine can be produced without causing land subsidence.

Very large resource; volume tied to gas output and subsidence limits.

Deep, iodine-rich brines are pumped, sometimes from oilfield wastewater, and iodine is stripped in small plants near the wells. In the US three companies operate in northwestern Oklahoma; one opened an eighth plant and raised output about 11% in H1 2025 (USGS).

Modular and quick to add; small plants and dependence on brine volumes.

Iodine is recovered from spent X-ray contrast media, LCD film manufacture and chemical process streams and purified for reuse.

Reduces primary demand; limited by dispersed end uses.

By-product supply

Iodine is a co-product of nitrates in Chile and a by-product of gas and brine in Japan, the US and Central Asia. Japanese and US output depends on gas and brine volumes, so supply responds slowly to price; Chile's caliche producers are the only large swing source, which gives SQM pricing power.

Who does it: global

Who does it: India

India has no iodine production listed by USGS (2026) and is the second-largest importer (13.1% of world import value in 2024, Comtrade), buying crude iodine for pharmaceuticals, contrast media and iodised salt. Iodine is not on India's 2023 critical list.