Abstract:

A precise accounting of urban iron and steel stocks could provide scientific basis for predicting future iron (including steel) demand, forecasting scrap steel generation, and informing relevant resource and environmental management strategies and policies. Studies on in-use stocks at city level, especially in China, have far less been paid attention to by scientific community comparing to them at country level, although it is still crucial to solve urban waste management and resource recycling problem. Chongqing, one of the four municipalities in China, is a representative city in West China with the largest population between all Chinese cities. Hence, in this study, we selected Chongqing to estimate its in-use iron stock levels and its sector distribution from 1985 to 2014 by applying a statistics-based bottom-up approach within its whole administrative boundary. A huge effort was made to establish a more elaborate iron and steel containing product inventory and collect data of product amount and iron intensities of each product. Social-economic drivers of stocks growth were further analyzed by IPAT equation that could easily quantify the impact for each factor. Our main findings include: (1) Both total and per capita iron stocks have increased by more than 10 times in the last 30 years and reached 59 million tons and 1.748t/cap in 2014, respectively. (2) Chongqing shows the lowest iron and steel stock among it and other two cities reported in the literature (Handan, China and New Haven, USA). However, it has similar distribution structure among different sectors (e.g., with the largest share in the building sector). (3) Economic growth and population positively contribute to stock growth. Alternatively, the technology shows a negative effect, leading to a decreasing trend for future iron demand in Chongqing.

Key words: material flow analysis, iron and steel stocks, bottom-up method, IPAT equation, driving force analysis, Chongqing