Industrial metabolism of copper and sulfur in a copper-specific eco-industrial park in China

Copper concentrate with high copper and sulfur content is the most important raw material in the copper industry. With the scarcity of copper ore resources, resource efficiency must be improved urgently to minimize further losses. This research seeks to elucidate the industrial metabolism of copper and sulfur in the copper smelting process using substance flow analysis and in turn aid in the optimization of production processes. A general model is constructed, and six indices are proposed to quantify and evaluate copper and sulfur metabolisms as well as the economic performance of the system. The Xiangguang Eco-industrial Park (XGEIP), which is a typical sector-specific industrial park in China that mainly caters to enterprises dealing with copper smelting and cathode copper deep processing, is chosen for the case study. On the basis of a five-year in-depth data collection and verification, this research presents the dynamic changes of copper and sulfur metabolism in the XGEIP. The results show that the resource utilization efficiencies of copper and sulfur increased year by year while the environmental impact decreased from 2008 to 2012. In 2012, resource utilization efficiencies of copper and sulfur reached 99.11% and 98.84%, respectively. Copper loss occurred mostly in the disposal of slag tailings (0.65%) while sulfur loss was observed mostly in the waste gas (0.66%). The environmental factors of copper and sulfur both decreased to 0.014 ton/ton in the system, falling well within the value range of bulk chemicals (i.e., <1 to 5). Meanwhile, the resource productivity of the copper concentrate underwent rapid growth with the extension of industrial chains during this period. In 2012, the resource productivity reached 6.20 thousand Yuan/ton, which showed an increase of 786% from that in 2008. These indices indicated that the XGEIP exhibited high productivity and low environmental impact. The results of this work can serve as a reference for decision makers in planning the future of the XGEIP and the development of the copper smelting industry.