Study Of Various Anionic Comprehensive Bioleaching For Metal Elements In Electronic Waste

As the level of society information increase,the amount of e-waste growth stagger.It will become a major problem for the human society.Meanwhile,electronic waste,will be the greatest pollution source, annually produce large amounts of hazardous toxic waste.However,there are a large number of reusable materials in the electronic waste.Its recovery and utilization can not only reduce environmental pollution,but also slow down the shortage of resources. Therefore,how to deal with growing electronic waste in an environmentally friendly manner has been a common concern all around the world.In this study,based on the elemental analysis for more than twenty kinds of metal elements in electronic waste using ICP-AES,against the high level characteristic of copper,gold,silver and so on,we propose the method of using Ferrousoxide Thiobacillus leaching where the metal element and intensive microorganisms leaching by anionic.There will be a certain significance on the industrial application of bileaching technology.The results shows that:1. Collect the basic information on different types of electronic waste and the electronic waste information database was established. Analyze the element content and estimate the economic value:the economic value in 1 ton hard disk is more than 102,957 yuan. All over the world the loss economic value is conservatively estimated 50 billion yuan. And 1 ton phone’s PCB board reserves valuable metal elements about 1,456,345 yuan.For China’s 800 million mobile phone ownership,the economic value will be as much as 10 billion.2. Under the initial conditions of the leaching system at pH=2.5,120r/min,25℃, through leaching experiments for PCB boards、components and other types of intractable electronic waste, determine strengthening method in next leaching experiments:single strain of Thiobacillus ferrooxidans as to be strengthened object.3. Under the same incolum size、the same dipped material quality and the same culture conditions, different anion respectively, the leaching rate of metal elements results from T.f. The experiments show that:fluoride ion is most obvious strengthening effect for T.f in all experimental group anion.4. Under different fluoride concentration、differetn contact time and different solid-liquid ratio, determine the optimum conditions for the synergistic effect of the fluoride ion:fluorine ion concentration of 10 mg/L、contact time 24h and solid-liquid ratio 1:250.5. Under optimal conditions, study the fluoride ion collaborative Thiobacillus ferrooxidans leaching waste printed circuit boards, find that the leaching rate as fluoride ion addition is higher than the blank group, and further compare the leaching effect of the noble metal elements、rare earth elements and other types metal elements in two groups, wherein the enhanced leaching rate of the noble metal elements is most obvious, which is increased by 10%-20%; has also been significantly improved of rare earth elements and other type metal elements more than 5%.