| The process of leaching Au from the waste printed circuit board (WPCB)is studied. The technique used in this article is basis on the analysis of more than 20 kinds of metal ultimate in a certain waste PCB with Atomic Absorption Spectrometry(AAS) and ICE In this PCB, the content of Cu is very high. And I remove Cu through copper-ammonia solution. This method can make an effect on removing low-priced metal. And I can get pure Cu from distilling the remain solution of reaction, so this method can kill two birds with one stone.After pretreatment, I leach Au by the reaction between thiosulfate and remain solid of pretreatment. In this reaction, I put CuSO4 or NaCl in it. And I want to find the best conditions of reaction.The proper factors of CHSO4 put in:PH=10;t=50℃;reaction time=3h;Cu2+=0.03mol/l; NH3=0.45mol/lThe proper factors of NaCl put in: PH=10;t=40℃;reaction time=4h;[Cl-]=0.8mol/lWhen NaCl put in reaction, the efficiency of leaching still high. And in this method, we will not carry more metal into the remain solution of reaction. It is important to the next reaction. In the next reaction, I get Au by Zn. Just like previous reaction, I want to find a proper factors.The factors is: PH=9.5; t=30℃; reaction time=20min; Zn=lg... |
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