Study On Extraction Technology Of Gold In Waste Computers

The paper mainly comment from waste computers' component,treatment technologies both at home and abroad,analysis contamination of PCB and so on,PCB has becoming hot spot at present in research field of solid waste studies because it is rich in recycling expensive and base metals.At the same time solvent extraction technology is widely used in extraction of precious metals because of handle simply,separation efficiency,high recovery,product purity and low cost.The thesis studies from pretreatment of PCB,the main processes is computer circuit boards through the heating stripping electronic components-circuit boards(Bare Board) smash-material sieving-stripping method in acid and base-preparation gold liquid by chloroazotic acid.After pretreatment,extraction gold by MIBK and n-propanol.In extraction experiment of MIBK,adjusting the time,solid and liquid proportion,acidity,temperature and the content of gold,measure density in extract liquid and spare liquid by atomic absorption, compute content of gold and extracting rate,analyze impaction by changing indicators.In system of n-propanol-Nacl-KBr by adjusting the amount of Nacl,concentration of KBr,time, acidity and other indicators,measure density in extract liquid and spare liquid by atomic absorption,Study on the impacting by changing indicators.Also study on the purification and recovery of anti-extraction gold and extraction liquid.The results show that:the best experimental conditions of MIBK:solid and liquid proportion is 0.6,oscillating extracts frequency is(100 r/min),extraction time is 15 min, temperature is 40℃,extraction rate is 97.14%,when gold content in the gold liquid is more than 30μg,extraction rate is more than 98%,and increase gold content,the extraction rate is not change significantly.In system of 1-propanol- Nacl-KBr,it get to extraction balance when Nacl is 2.0 g,KBr concentration is 0.20 mg/mL,extraction is 2 minutes,the extraction rate of 97.45%,quickly extraction speed and highly extraction rate;collected by the two methods of extraction liquid can make use of oxalic acid to anti-extraction,effect is good.The purification to extraction agent adopt distillation condensation reclaim method,the recoveries are greater than 98%,recovery of MIBK and n-propanol can be used again,raise efficiency while reducing the costs of extraction.The study provide theory technology for extracting gold,in shortage of resources in the present-day society,efficient recovery of precious metals(Au) in waste computers has become a research point,and it is significance significant in improving precious metals(Au) extraction rate in waste computer.