The variation of copper,gold and silver content over time in 72 waste printed circuit boards samples from 9 types,8 years,including television,computer,air conditioning and refrigerator were analyzed.There is a significant difference in copper content among different types of waste circuit boards,the average value for washing machine circuit boards is the lowest(4.58%)and the average value for telephone circuit boards is highest(20.38%).The gold and silver content in waste circuit boards decrease year by year.The average gold content in telephone circuit boards is the lowest(0.17 g/t),while the average gold content in mobile phone circuit boards is the highest(305.69 g/t).The silver content in telephone circuit boards is the lowest(3.19 g/t),and the silver content in computer circuit boards is the highest(524.12 g/t).The economic value of different types of circuit boards varies greatly,of which the mobile phone circuit boards have the highest economic value(186 000 RMB/t),the economic value of gold account for 168 000 RMB/t,and washing machine circuit boards having the lowest economic value(6 000 RMB/t).Based on many years of production experience,some suggestions for controlling the composition of feeding materials for pyrometallurgical treatment of waste circuit boards are put forward.
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