Assay Determination Of Precious Metals In Waste Printed Circuit Boards Of Spent Mobile Phone

With the development of economy and society, the amount of waste electrical and electronic equipment(WEEE) keeps rising rapidly. WEEE has been regarded as the “Urban Mine” for its content of value elements which is much higher than crude ore, and the hazardous elements are harmful to the environment. Thus, the recycling of WEEE draws lots of social attention and academic focuses and researches.Waste printed circuit board(WPCB) of spent mobile phone, as one typical type of E-waste, has a large amount of precious metals which draws significant attentions. The component of precious metals in raw material plays an important role in the determination of metallurgical process of both pyrometallurgy and hydrometallurgy for the complete component of PCB, such as the selection of slag form and ingredient in pyrometallurgy, and the selection of leachate in hydrometallurgy. Thus, it is important to precisely determine the component of precious metals in PCB. This paper developed a method for the determination of the component of precious metals in WPCBs in order to provide support for efficient recovery of the precious metals.Unroasting-leaching experiment was performed and the content of Au, Ag, Pd was determined which was 119g/t, 49.84g/t, 13.56g/t, respectively. Roasting of the raw material and leaching of hydrofluoric acid were added to the process based on the analysis of experimental and detective results.In roasting-leaching experiment, PCB of cellphone was proposed by a 6-step entire hydro-process after dismantling, roasting and 2-grade crushing. The component of Au, Ag, Pd was found to be 120g/t, 312.30g/t, 42.55g/t, respectively, based on the steps of possible elements lost such as the tail gas during roasting process.Aiming at detecting the component of 3 main precious metals(Au, Ag, Pd), the most objective component of raw material at present condition of experiment and detection was obtained though designed process and the analysis of detection. The conclusion provides reference and consulting for component detection of WPCBs, as the raw material of E-waste recycling, with pyrometallurgy or hydrometallurgy in both laboratory scale and industrialization.