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The acidic etching waste produced by the printed circuit board factory is treated by chemical acid-base neutralization method. The Cu2+ ions in the etching waste liquid are formed into copper oxide through a chemical reaction process. In the re-reaction process, we are looking for research on how to reduce the complicated process and recover the copper oxide in the shortest time and with low consumption cost.
In the course of this research, experiments were carried out with the acidic etching waste liquid produced in the etching process section of a large domestic PCB board factory. In the experiment, take 100ml of acidic etching waste liquid in a beaker (pH: 1↓, Cu2+ ion content is about ≧13.5g/L), then take 45% sodium hydroxide solution and slowly add it to the etching waste liquid waste liquid and proceed. Stirring (the stirring speed should be above 200RPM) the pH of the solution is from 1↓ to pH>12, and OH- reacts with Cu2+ to form copper hydroxide precipitate Cu(OH2). During the process, how much volume of 45% sodium hydroxide solution needs to be consumed to completely react the 100ml acid etching waste liquid.
Then take the same 100ml of acidic etching waste liquid and the volume of the 45% sodium hydroxide solution obtained in the preliminary experiment; perform another experiment. In this experimental process, do not add slowly, but instantly pour the known 45% sodium hydroxide solution into the acid etching waste liquid for mixing reaction; during the reaction process, the heat of reaction and hydroxide generated by acid-base neutralization In the process of combining sodium and copper ions, copper oxide slurry (or sludge) is obtained. The copper oxide is obtained by filtration, and the filtered water is analyzed for the concentration of Cu2+ in the water. The filtered copper oxide is taken to the oven and dried at 105°C for 4 hours to reduce the moisture content. Obtained copper oxide lumps and then analyzed its Cu2+ weight percentage to find that it is 60-75%.
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