BEIJING - China's output of secondary non-ferrous metals, those recycled from scrap metals, rose 3.67 percent year on year in 2012 to exceed 10 million tons, almost one-third of its output of primary non-ferrous metals, an industry association said on Thursday.

In 2012, a total of 6.6 million tons of domestic scrap aluminum, copper, zinc and lead, the four major types of non-ferrous metals, were recycled, up 5.09 percent year on year, the recycling metal arm of the China Non-ferrous Metals Industry Association told a press conference.

The association also said China has become the world's largest importer of scrap non-ferrous metals.

From 2002 to 2012, the efforts of Chinese non-ferrous metal recyclers were equal to a saving of 139 million tons of standard coal and 12.3 billion cubic meters of water that would have been consumed in producing the same output of primary non-ferrous metals, the association said.

Wang Jiwei, vice president of its recycling metal branch, said the industry is faced with many challenges, including a decline of scrap metals resulting from low recovery rate at home and slumping imports from abroad, as well as limited industry innovation and weak demand.

In the first three quarters of 2013, China produced 7.22 million tons of major secondary non-ferrous metals, down 5.1 percent from the same period last year, according to Wang.

The industry will optimize its structure and hone its ability for technological innovation, said Wang, adding that an international forum will be held in November to help enterprises tackle problems in their production and business operation.