Currently, the number of the waste printed circuit boards (WPCB) is increasing. The technologies of extracting and reclaiming of the value of the metallic fraction of WPCB have been used widely because of the major economic driving force. But the non-metallic fractions (NMFs), which take up almost 70wt% of waste WPCB, were mainly treated by combustion or land filling in the past. However, combustion of the NMFs will cause the formation of highly toxic polybrominated dibenzodioxins and dibenxofurans (PBDD/Fs). Land filling of the NMFs will lead to secondly pollution that caused by heavy meatals and brominated flame retardants (BFRs) leaching to the groundwater. Therefore, recycling of the NMFs from waste PCBs is drawing more and more attention from the public and the governments. How to recycle the NMFs environmental soundly has become a significant topic in recycling of WPCB. This paper briefly introduced that the damage of WPCB and the recycling methods of epoxy resin. The method was established for recycling of WPCB by using solvent extraction. And the optimal conditions were attained through experiments: the reaction temperature was 80°C、the reaction time was 3h、the concentration of nitrate acid was 8 mol/l, the amount of nitrate acid : the quality of WPCB was 50ml/10g.
With the development of industrial production and the improvement people's living standards, all kinds of discharged wastewater cause serious pollution for nitrogen and phosphorus.In this study, the water of Dianchi lake was treated by Ultrasonic – flocculation. The results show ultrasound-flocculation sedimentation is better than only flocculation sedimentation in removing the total phosphorus, total nitrogen and reducing COD, BOD and turbidity respectively increased 16.19%, 12.71%, 9.1%, 20%, 18.3%.
Phosphate ore was decomposed by using thermogravimetric (TG) and differential scanning calorimetric (DSC). The TG-DSC curves contained different sizes and heating rates. The results showed that phosphate ore had four weight loss stages at the range of 40 ~ 1100°C. With the particle size decreasing, the third weight loss stage became more obvious in TG curves and the endothermic peak became sharper in DSC curve ; the starting and ending temperature of thermal decomposition process moved to higher,the weight loss rate also tended to increase; the activation energy of phosphate ore endothermic decomposition process was calculated by Owaza method in 600~800°C, the average activation energy was 202.80 kJ / mol. It provided a basis for the utilizing of phosphate ore.
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