Study On The Synthesis Of β-diketones And The Extraction Process Of Copper From Alkaline Etching Liquid Of PCB

With the rapid development of China’s electronics industry, the printed circuit board (PCB) and its related industries have grown rapidly in recent years. However, the process of alkaline etching of PCB generated large amounts of copper and ammonia waste, which will cause great environmental pollution and economic losses discharged directly without any treatment. The copper present in the effluents must be recovered on account of economical and environmental reasons. Thus, the aim of this work is the extraction of copper from alkaline etching liquid of PCB by using of P-diketone synthesized with iso-octyl acid.Isooctyl methyl is synthesized by using of iso-octyl acid and methnol catalyzed by H2SO4. The effect of material ratio, time, amount of catalyst and temperature on the yield of isooctyl methyl is studied. The optimal condition is as follow:molar ratio of ethylhexanoate and methanol is1:2.5, and with iso-octyl acid=16mL, H2SO4=3mL. the reaction time is0.5hour and the temperature is120℃. The yield of isooctyl methyl is99%. β-diketone is synthesized by using of isooctyl methyl and acetophenone. The reaction condition is:the molar ratio of acetophenone and methyl octanoate is1:1.1, the temperature is170℃, the reaction time is3hours, the yield of β-diketone is68%. The target products are identified as iso-octyl acid methyl esters and β-diketones, which are qualitatively analyzed by infrared spectroscopy (IR) and mass spectrometry (MS).Copper is extracted from alkaline etching liquid of PCB by using β-diketones as extranctant and sulfonated kerosene as dilute. With ethching liquid containing112g/L Cu and5.7mol/L NH3, the single stage and multistage extractive processes are investigated in details.The optimum extraction conditions of single stage process are as follow: the concentration of β-diketones is60%, the phase ratio (O/A) is2:1and the temperature is30℃. It shows that the extraction percentage can reach54.8%without the adjustment of pH value, and the saturated extraction of copper is64.03g/L after3minutes treatment. The thermal effect of extraction experimental (△H) is8.95KJ/mol. In addition, the extraction percentage with the processing of4-stage cross-flow extraction and3-stage countercurrent extraction are94.78%and76.01%. As for stripping process, the optimal conditions are:C(H2SO4) is3mol/L; O/A is1:1; temperature is60℃, the stripping rate of copper up to99%. Under, single-stage extraction-stripping conditions, the copper recovery rate of copper up to54.25%. Etching solution can be returned to the etched line cycle after being extracted.