Tungsten is deemed a critical raw material by many nations, given its irreplaceable use in industrial and military applications. In particular, much concern has been drawn to China's high share in global tungsten supply. While various studies have focused on the criticality of tungsten, few have specifically explored how tungsten is produced, consumed, and traded. In this paper, the dynamic material flow analysis is applied to quantify China's annual tungsten cycle from 1949 - 2017. It is estimated that total tungsten mined from ores in China over the past 68-year period is similar to 2500 kilo-tons (kt). Among those, similar to 750 kt of tungsten has been exported to other countries, and around 970 kt tungsten is domestically consumed. It is noted approximate to 1720 kt has been lost from mining, production, and end-of-life stage, and merely similar to 130 kt has been recycled as end-of-life scrap. Our material flow analysis further refined China's tungsten dominance. Although China currently dominates the global production of tungsten, this dominance will not extend too far into the future given China's limited share of world tungsten reserves and its declining ore quality. Our trade flow analysis reveals that China imported 35 kt of high valueadded downstream tungsten products from outside manufacturers, whose mineral resource was originally imported from China. At present, China by itself is experiencing overcapacity issues in the primary production, which discourages the recycling of at end-of-life (EoL) stage and makes the EoL recycling rate only 10%. It is noted that the percentage of Chinese tungsten for domestic consumption has been increasing in the past few years. This highlights the need for systematic measures from stakeholders along the tungsten cycle to promote sustainable practices for efficient tungsten production, use, and recycling in China. Meanwhile, the results also suggest the importance of monitoring the criticality of tungsten and other critical minerals from a dynamic and material cycle perspective.

Given copper mineral is becoming rarer and harder to obtain, China needs to find alternative sources to meet its future demand. Copper in-use stocks are potential reservoirs accessible for urban mining. Thus, detailed analyses of domestic copper in-use stocks and flows are required, especially for a high-resolution mapping of the spatio-temporal distribution of copper stocks and flows in China. This paper firstly constructs the China's provincial copper in-use stocks (CPCS) database by compiling around 74 types of copper-containing products in 31 provinces from 1978 to 2016, and estimates copper in-use stocks, demand, and scrap generation in each province. Results indicate that (1) the total copper in-use stocks in China is about 90 MMT (million metric tons) in 2016, which is around four times as much as China's copper ore reserves; (2) Per-capita copper in-use stocks increased from 14 kg in 1978 to 75 kg in 2016 with large regional disparity across the whole country, and is still below the western nations' level; (3) Total copper scrap generation increased rapidly from 0.003 MMT in 1979 to 1.50 MMT in 2016, mainly in the eastern coastal region, indicating that the time window for copper urban mining is opening in the region. This study can help clarify the location, amount, and category of copper in-use stocks available for future urban mining, and tailor more regional-specific resource and waste management policies for sustainable copper management in China. (C) 2020 Elsevier Ltd. All rights reserved.