40%, the most is copper, in addition to gold, aluminum, nickel, lead, silicon and other metals, while the content of rich minerals in nature is only 3 ~ 5%. Statistics show that the gold content per ton of waste circuit boards reaches about1000g. Now, with the improvement of technology and the reduction of cost, about 300 grams of gold can still be extracted from each ton of waste circuit boards, and the market price is about 30 thousand yuan. Printed circuit board waste residue can be buried or used as building materials.