Environmental impacts analysis of titanium sponge production using Kroll process in China

Abstract

Life cycle assessment of titanium sponge production using Kroll process in China was conducted based on ReCiPe method. The life cycle inventory and environmental impacts of the main processes was calculated. The main factors and sources that cause environmental pressure were identified. In addition, sensitivity analysis of the allocation scenarios for energy consumption in the V-Ti magnetite ore mining and dressing and main auxiliary materials and power consumption were discussed in detail. The results indicated that the electrolysis of magnesium chloride and the smelting of titanium slag accounted for 39.6% and 22.4% of the total impact of Kroll process, respectively. The accumulative energy consumption of the titanium sponge production in China was 423 GJ/t. Electric power accounted for 66% of the accumulative energy consumption. The sensitivity analysis showed that the scenario based on the mass of the target products in ore mining and dressing process was more feasible. The allocation scenarios based on the mass of iron or titanium dioxide exerted negligible impact on the final results. The electricity consumption exhibited the highest sensitivity among all the environmental impact categories except for the metal depletion. Toward cleaner technologies implementation in China titanium sponge production, the potential and effectiveness of the effort were quantified. In particular, the electric power consumption and the characterisation results for particulate matter formation and photochemical oxidant formation were reduced by 17%, 54% and 28%, respectively. The overall environmental impact decreased by 21%. The adoption of advanced and mature techniques and equipment is of a greater practical significance to the cleaner production of titanium sponge.