The most-traded copper contract on the Shanghai Futures Exchange rose as much as 1.6% to a one-week high of $6,813.54 a tonne
The higher tariffs would affect everything from apparel and footwear to fireworks and cellphones
China had insisted that they treat it as a "market economy"
Weak data reinforces need for more growth-boosting steps
The issue has been festering since 2011, when scores of Chinese corporates trading on U.S. exchanges were accused of accounting irregularities
China would actively boost imports to help balance trade, the cabinet said