Structure of international iron flow: Based on substance flow analysis and complex network

Iron is a basic substance in the manufacturing industry of a country. The industry chain of iron and steel is an integrated and complicated system with substance exchange through import and export. Features and structure of this system can reveal the global pattern of the iron and steel industry chain. This study aims to quantitatively analyze the evolution of features and structure of international iron flow by combining the theory of Substance Flow Analysis and Complex Network. The network model was constructed based on the iron substance flow embodied in the trade among all the countries in the world. Trade density, concentration of trade activities, concentration of trade volumes, and hierarchy structure of the network were studied. Results show that the trade density of iron-contained commodities can act as the “barometer” of world economy; the concentration of trade activities shows a reverse relationship with the world economic prosperity; the trade volumes are highly concentrated in a small number of countries; and the hierarchy structure of the network of international iron flow is becoming more obvious. Some policy implications according to the results were provided.