Quantitative estimation of social stock for metals Al and Cu in China

Social stock for metal determines secondary or recoverable resources to a certain extent. Top-down analysis method for the studying of metal in social stock was given. Influences of metal consumption under three circumstances, that is keeping constant, varying in a linear trend and in an exponential trend, on one kind of metal's social stock, recyclable ratio and average age were analyzed. Al-contents and Cu-contents in social stock for China during the period 2006–2009 were calculated. The results reveal that Al-contents and Cu-contents in social stock kept increasing and reached 88.9 million tons and 51.4 millions tons in 2009, respectively, their average recyclable ratios are 1.45% and 0.30%, and the average ages are 4.65 years and 6.89 years, respectively. The recyclable ratios and average ages of Al-contents and Cu-contents in social stock will rise in future along with the decline of the increasing rate of aluminum consumption and copper consumption.