Research On Dispersion Strengthening Of Flotation Slurry And Sorting Test Of Printed Circuit Boards Of Waste Mobile Phone

With the rapid development of the electronics industry,mobile phone product update speed continues to accelerate.There are as many as 70 million waste mobile phones in China each year and this data will continue to grow.As a core component in waste mobile phones,printed circuit boards are necessary for efficient resource recycling due to their high metal content and pollution.At present,mechanical methods have become the main processing technology for waste printed circuit boards due to low pollution and high recovery.For the processing of fine material of crushed products,some mechanical methods are difficult to achieve better sorting effect due to particle size limitation.Flotation is used as a processing method because of its advantages in handling fine particles.However,the current research on the waste printed circuit boards for flotation processing is limited to direct flotation for crushed product and lacks in-depth analysis and effective solutions for the low efficiency of fine particle material sorting.Therefore,this paper through in-depth theoretical analysis and experimental research to achieve efficient recycling of metal in waste printed circuit boards.SEM-EDS was applied to study the appearance and surface element distribution of glass fiber and copper,it was found that the glass fiber exists in a bundle and the surface carbon content is 49.42%,which contributes to the glass fiber floating.The copper surface contains many nodules and has a carbon content of 32.54%.XPS analysis further found that copper mainly exists in the form of CuO,Cu?Met?and Al₂Cu metal compounds,and their contents are 28.57%,32.86%and 38.57%,respectively.FT-IR analysis found that the organic structure of PCBs and epoxy resin have the same molecular structure,which provides a basis for subsequent flotation agent selection and drug adsorption mechanism.The nonmetal surface energy was calculated,it can be found that the van der Waals component occupied 94.06%of the nonmetal surface energy,indicating that the surface of the nonmetal particles mainly belongs to the non-polar surface and exhibits strong hydrophobicity.On this basis,the reasons for the nonmetal agglomeration were studied.It was found that the main force of agglomeration between nonmetal particles was hydrophobic attraction.Further,the dispersibility of the nonmetal particles is improved by the addition of the organic dispersant,and the dispersion mechanism of the dispersant to the nonmetal particles is discussed.Finally,by studying the adsorption mechanism of organic dispersion agents on the surface of nonmetal particles,it was found that van der Waals forces and hydrogen bonds help the drug to adsorb on the surface of nonmetal particles and the adsorption amount is sodium lignosulfonate>tannic acid>hydroxymethylcellulose.The effect of dispersant on the flotation effect was studied,it was found that the copper recovery showed an increasing trend with the increase of the amount of dispersant added.However,when the added amount was too high,the metal copper grade in the sink decreased sharply.Therefore,proper addition of a dispersant can increase the metal recovery.Further,by analyzing the sink yield of the same amount of dispersant,it was found that the interaction strength of sodium lignosulfonate>tannic acid>hydroxymethylcellulose.This is mainly due to the strong negative polarity of the polar functional group in the dispersant and quantitative influence the strength of hydrogen bonding.In addition,as the amount of collector added increases,the grade of metal in the concentrate shows an increasing trend,and the effect of dodecylamine is greater than that of kerosene.This is because the cationic collector can achieve electrostatic adsorption on nonmetal particles that are negatively charged on the surface.