Urban mining: A solution to China’s resource crisis?

China has steadily increased its import of mineral resources. The increased demand may be attributed to rapid industrialization and urbanization, and this demand is projected to grow in the coming years as China progresses economically. In order to secure a constant supply of the important mineral resources China must take strategic steps. Urban mining (UM), which includes reclaiming secondary resources from urban wastes or obsolete materials, could be one such strategic step. Experts say urban mining has the potential to mitigate China's resource scarcity partially — if not fully.

A study published in the Journal for Industrial Ecology looks at the potential of urban mining in China from 2010 to 2040 under various scenarios based on the different resource use and recovery strategies. The authors also propose measures to promote urban mining in China. The study focuses on determining the UM potential for four metals that are in high demand but domestic availability is scarce: Iron (Fe), Copper (Cu), Aluminum (Al) and Lead (Pb). Foreign imports make up for the wide gap in domestic supply. According to the paper, China's external dependence for these metals in 2010 was: For iron, 51 percent; copper, 72 percent; aluminum, 48 percent; and lead, 26 percent. To determine the UM potential, authors simulated the current metabolic processes and flow of metals and project future demand, scrapping, and recycling of these metals. Three scenarios are considered for the study- business-as-usual (BAS) scenario, low resource (LR) scenario and strengthened recovery (SR) scenario. The environmental and energy benefits of using secondary metals were also evaluated.

The UM potential for all the four metals increases from 2010 to 2040. By the year 2030, copper and iron recovery rates will be higher than the import quantities, making recovery of these metals the main source of domestic supply. It is projected that primary sources of these two metals will be used up in the next 30 years. In the case of lead, the domestic source will be used up in 10 years. The shortage in primary metals will be substituted by the use of secondary metals recovered from the waste streams. From 2020 to 2040 the substitution rate for copper will increase to 19.6 percent; for iron, it will increase by 48.8 percent.

Ultimately the external dependence will be below 10 percent and there will be guaranteed supply of copper and iron. However, for aluminum and lead the resource supply will still be a challenge as the external dependence will decrease by only 4.6 percent and 7 percent, respectively. As far as energy savings from the use of secondary metals, it is significant for iron and aluminum; it would not be the case of recycled copper and lead. Secondary metal use also reduces water consumption, solid waste generation, and sulfur emissions.

The analysis shows that increasing resource demand will continue to tax China's ability to acquire resources. Hence, China must adopt a combination of strategies encouraging enhanced resource recovery and efficient consumption, as the authors suggest. The current flaws in the recycling system must be addressed to enable a hassle free urban mining system.

In addition to proposed government-led "demonstration urban mines," promotion of core recycling technologies among the recyclers should also be explored. Promoting UM-based policies and shifting away from import-based policies will help reduce the import costs of mineral resources and the mineral resources shortage.