Research On Copper Recovery From Waste Printed Circuit Boards By Hydrometallurgical Methods And Preparing Ultrafine Copper Powder

This topic for the research status of waste printed circuit boards recycling were reviewed in detail,and distinguish the advantages and disadvantages of various technologies.Finally,find out a kind of procedure which includes mechanical pretreatment circuit boards,copper sulfate-hydrochloric acid and n-butyl amine leaching system-by extracting and reextracting method to enrich copper sulfate solution-two stage reduction method of preparing ultrafine copper powder,achieve thing the aim of recycling the discarded resources efficiently,no pollution,high added value etc.Main research conclusions can be seen as follow:?1?WPCB has complex structure and special physicochemical properties.In order to achieve effective separation and reclaim of various marketable materials,pretreat them by dismantling and comminuting firstly.Then,pretreat powder got from mechanical crushing in nitrolysis by using aquaregia-hydrofluoric acid-perchloric acid.This method has the advantage of high precision,good repeatability,reproducibility.?2?Leaching system of CuSO₄-HCl-C4H11 N to leaching of copper ion from the PCB has good selectivity and high leaching rate.The best leaching condition is that stirring intensity: 400⁶00rpm,concentration of CuSO₄ is 19.5g/L,concentration of HCl is 1.8mol/L,C4H11 N concentration is 0.3mol/L,temperature 55?,leaching time is 6h.Under the best condition,the average copper leaching efficiency reach 97.67%;relative standard deviation is 0.41;better precision;realizes the copper's transferring in PCB from solid phase into the liquid phase;give effective support to the main procedure recycling copper from WPCB,what's more it establishes a good basis to the preparation of ultrafine copper powder.?3?We can get baci-extraction solution with less impurity,high copper content and achieve good separation and excellent stability after extraction and sulfuric acid reverse extraction of the copper leaching system by using LK-C2 as extractant.Under the best leaching condition of pH 2.0,LK-C2 volume fraction is 15%,ratio is O/A=1:1,extraction time is 3min.The copper extraction rate can reach 99.98%.The best baci-extraction condition is as follows: sulfuric acid 2mol/L,ratio O/A=2:1,fully shocking time 5min under room temperature.Final baci-extraction rate of copper was up to 91.32%,and copper ion concentration in the baci-extraction solution was 39.52 g/L.We can get CuSO₄·5H₂O as raw materials for the preparation of ultrafine copper powder after crystallizing the baci-extraction solution.?4?The ultrafine copper powders produced by the two steps reduction which use glucose prereduction and ascorbic acid as reducing agent.The best environment is that the temperature is 75?,pH is 14,w=0.03 gelatin putted in during stirring.Firstly,deoxidize glucose under strong alkali in 60 min.Then,add 100 mL ascorbic acid solution whose concentration is 0.3mol/L slowly and stand for 24 h after 60min's reaction.Put ultrafine copper powder which has been soaked cleaning by 3m L tributyl phosphate in the solution for surface modification after separating the upper clean liquid.We can get ultrafine copper powder with average particle size of 500 nm,high crystallinity,good dispersion,no agglomeration phenomenon and good oxidation resistance.