Towards sustainable TiO₂ production: an investigation of environmental impacts of ilmenite and rutile processing routes in Australia

This paper presents life-cycle environmental impacts and health hazards of the ilmenite and rutile processing routes which are very little explored despite a significant quantity of production worldwide. The study is carried out through a life-cycle environmental-impact assessment of the ilmenite and rutile mining production processes in Australia, using the International Reference Life Cycle Data System (ILCD) method under 14 significant impact categories and the Cumulative Energy Demand (CED) method for 10 significant impact categories. The dataset is collected from EcoInvent and the Australian Life cycle assessment database considering Australia as the geographic region. The major impact categories are climate change, human health (cancer), human health (non-cancer), ecotoxicity, and eutrophication. The analysis results show that the highest impact is caused in climate change, at 0.295 kg CO₂ eq, which is due to the large amount of electricity consumption in the ilmenite extraction process. Then, human toxicity-non cancer effects (4.42E-09 CTUh) and particulate matter (0.000155 kg PM 2.5 eq) are also noteworthy. Water resources depletion is affected due to the chemical emissions from ilmenite ore, which are found to be 0.00163 m³ water eq. Rutile production impacts greatly on climate change at 1.535 kg CO₂ eq owing to large-scale electricity consumption. Electricity consumption for rutile also affects human toxicity-non cancer (2.3E-8 CTUh), particulate matter (0.00081 kg PM2.5 eq), and terrestrial eutrophication (0.024 molc N eq). Water-resources depletion from rutile is due to the ore, which are found to be 0.0085 m³ water eq. The comparative assessment between ilmenite and rutile implies that rutile has more impact on the environment than ilmenite due to the electricity consumption and fossil fuel consumption. This result is validated through further analysis using the Cumulative Energy Demand method. A sensitivity analysis is also carried out to elucidate that the electricity grid mix from country-to-country contributes to sustainability by reducing the environmental impacts significantly.