Different zinc plating coating performance comparison
traditional galvanized process and mechanical zinc plating coating of the main performance comparisons are shown in table 1. Found in the comparative mechanical zinc coating corrosion resistance is far more than electricity galvanized, under the equal thickness of corrosion resistance and hot dip galvanized. Mechanical and the thickness of the galvanized layer is easy to control, can control the raw material to add in the 5 ~ 110 mu m any adjustments.different galvanizing technology's impact on the environment, the electricity galvanization wastewater is electric galvanized's impact on the environment. Because of the different plating technology, waste water treatment is also different, generally do not contain complexing agent and cyanide galvanization wastewater, only need to adjust the pH value and the right amount of flocculant, the zinc zinc oxide precipitate formation of hydrogen, after precipitation and filter the emissions and recycling. And wastewater containing complexing agent more ammonium salt galvanized, little experience in the chemical method of wastewater treatment. After plating passivation will make the waste water containing cyanide and heavy metals, escape chromium fog, nitrogen oxides, and acid fog at the same time, the destruction of urban environment, ecological. Hot dip galvanized galvanized points gas protection law and the method of drying solvent, the former environmental situation is better; The latter is seriously influenced on the environment. Drying solvent method because of the hot dip galvanizing process at high temperature, solvent, drying and plating workpiece pooling a large number of HCl gas evolution, zinc pool for a long time under high temperature, liquid zinc slag surface produces a large amount of ZnO, NH4Cl, workpiece after immersion plating aid and plating rinse with ZnCl2, NH4Cl solution spill, zinc and increased amount of ammonium ion in the waste water. Galvanizing industrial equipment generally used the zinc pool of open mode, so the hot galvanizing focuses on the environmental impact of the main pollution of the atmosphere. Such as HCl, ZnO dust, NH3, SO2, CO, etc.