Study On The Treatment Of Pyrophosphate Copper Plating Wastewater

In the production of PCB a large quantity of pyrophosphate copper plating wastewater is discharged, the main pollutants are copper and phosphorus, which is harmful to human body and environment. At present, removal of copper and phosphorus is the first purpose of the wastewater treatment. Meeting the emissions standards simultaneously for both is very difficult, and cannot function steadily. In this article, based on pyrophosphate copper plating wastewater as the research object, different methods was adopted to treat electroplating wastewater, the advantages and disadvantages are discussed. Provide a beneficial reference for the recyle of wastewa-ter like this, and get the following achievements:1) The treatment effect of chelating heavy metal wastewater by chemical precipitation is not ideal. In the process of neutralization precipitation treatment, the removal rate of Cu2+increased with the increase of pH, the removal rate of Cu2+ reached 44.2% when the pH was 12. The teratment effect of sulfide precipitation increased with the increase of dosing quantity and pH. When the pH was 10 and S/Cu was 10, the removal rate of Cu2+ reached 80%.2) In the process of ferrous sulfate, with the increase of dosing quantity and pH, and the extension of reaction and sedimentation time, water quality is becoming better. When the dosing quantity of FeSO4 ·7H2O was 0.96 g/L, the pH was 10, reaction and sedimentation time was 12 h, the removal rate of Cu2+ and TP reached 98.43% and 38.81% respectively. This method has a good removal effect of Cu2+, but for the removal of TP is not ideal, and a large amout of Fe3+ is contained in the water after treatment.3) The effect of calcium treatment is very good, with the increase of dosing quantity of CaCl2, pH and reaction time, the treatment efficiency is increased. When the dosing quantity of CaCl2 was 0.668 g/L, the pH was 9, and reaction time was 15 min, the concentration of Cu2+ and TP was 0.1 mg/L,0.43 mg/L respectively, the removal rate reached 99.78% and 99.70% respectively, when using Ca(OH)2 instead of CaCl2 can also achieve good treatment effect. The primary and secondary sequence of the impact factors on the treatment effect is:pH> calcium chloride dosing quantity> reaction time. But calcium treatment will increase the concentration of Ca2+, causing water hardening, large quantity of sludge is produced.4) The copper chloride method achieved good results in the treatment of this wastewater. When the dosing quantity of CuCl2 was 0.98 g/L, the pH was 6, and reaction time was 15 min, the concentration of Cu2+ and TP was 0.25 mg/L、0.63 mg/L respectively, the removal rate reached 99.45% and 99.56% respectively. The primary and secondary sequence of the impact factors on the treatment effect:pH value> reaction time> copper chloride dosing quantity. In the process pH and drug dosing quantity must be strictly controlled.5) Zinc chloride was adopted to handle zinc-nickel wastewater, the results show that:when the dosing quantity of ZnCl2 was 0.348 g/L, the pH was 6, and reaction time was 25 min, the concentration of Zn2+, Ni2+ and TP was 1.68 mg/L,1.85 mg/L and 0.49 mg/L respectively, the concentration of TP meet emissions standards, but other methods for further processing are needed for the removal of Zn2+ and Ni2+.6)Through the contrast of these methods get the conclusion:the treatment of this wastewater by traditional methods cannot recyle copper and phosphorusthe, and water quality is difficult to meet emissions standards, also has other disadvantages. However, the final water quality by copper chloride method meet emissions standards, and recycle Cu2+、P by pyrophosphate copper precipitation, this method as a new processing technology is much more advantageous, and has a certain practical significance.