Cradle-to-gate life cycle assessment of iodine production from caliche ore in Chile

PurposeIodine and its compounds have several industrial uses, primarily in nutrition and healthcare. So far, no specific LCA data for industrial iodine production are available. The purpose of this study is to provide the first LCA using primary industry data for iodine production from caliche ore in Chile.MethodsThe study is a process-based, attributional LCA and follows the relevant ISO standards 14040/44. Primary data were collected from the world's main producer representing their production for the years 2019 and 2020. Economic allocation was applied to deal with the by-product sodium nitrate. The impact assessment was performed with a set of CML 2001 indicators.Results and discussionCradle-to-gate total LCIA results per 1000 kg of iodine prill product include a GWP(100) of 1.48E+04 kg CO2 eq., an AP of 2.53E+02 kg SO2 eq., a POCP of 1.20E+01 kg C2H4 eq., an EP of 9.60E+00 kg PO43- eq., and an ADP fossil of 2.44E+05 MJ. The main contributor across process steps and for most impact categories is electricity consumption. Other hotspots include diesel combustion, hydrogen peroxide, sulfur, sulfuric acid, kerosene, and sodium hydroxide. A scenario analysis with renewable electricity revealed a reduction potential for all impact categories. As an example, the GWP could be reduced by 33-38%.ConclusionsThis study is the first LCA for iodine production from caliche ore based on primary industry data. The switch to renewable sources was identified as the main improvement potential for the hotspot electricity consumption, with a potential reduction of at least 25% for all impact categories except ODP.