Material flow and supply-demand feature of thulium in China

Limited insights have been obtained regarding the flows and stocks of thulium, the scarcest rare earth element. Thus, this study quantifies the thulium material flow from 2011 to 2020 in China, the largest thulium producer and reserve holder. Dynamic material flow analysis method is used and the demand and supply pattern of China's thulium is clarified. Results reveal that the final demand for thulium grows at an annual rate of 6.2%, reaching from 121 tonnes in 2011 to 208 tonnes in 2020, driven mainly by laser-related end-use sectors. Accumulative 1506 tonnes (80.7%) of domestically produced thulium in China originates from illegal mining during 2011-2020. This, combined with imported thulium compounds, bridges the significant gap between final demand and domestic legal supply. Moreover, 1422 tonnes of thulium are stocked in end-use sectors by 2020, with 30.8% in fiber-optic communication sector. A supply-demand gap has emerged since 2016 with thulium demand surpassing its domestic supply, which is projected to further widen in the future. Measures like promoting recycling and recovery, optimizing the trade patterns, and exploring material and technology substitution are proposed to mitigate such a gap.