Recovering and using technology of water in electroplating

[0016] Example 1

[0017] As shown in the figure, the cyanogen-containing washing water is added with 7 times the weight of sodium hypochlorite as -CN to destroy the complex state formed by -CN and metal ions, so that -CN is oxidized and the metal ions are in a free state; Chromium cleaning water added as Cr by weight 6+ 3.5 times of sodium metabisulfite, adjust the PH to 2.5 so that the Cr 6+ Reduced to Cr 3+; Then mixed with other cleaning water containing acid, alkali, copper, nickel, etc. is the comprehensive cleaning water. First, use a superposition filter to remove impurities with larger particles; then use a yarn core filter to filter and remove small particles above 5μ; then use a high-pressure pump to increase the pressure to make the pressure greater than the osmotic pressure, and enter the reverse osmosis treatment; Permeation treatment uses a neutral anti-pollution reverse osmosis membrane to remove the metal ions and produce RO water; finally, the pH value of the RO water is adjusted to neutral with sodium hydroxide, which is the reuse water. After testing, its conductivity is 85μ, and its salt rejection rate is 90%. This recycled water is used in the electroplating cleaning process and can replace clean tap water. After calculation, the recovery rate of water is 68%.

[0018] The concentrated water produced by reverse osmosis is neutralized with calcium oxide to adjust its acidity to near neutrality, and at the same time, the metal ions and -OH in it can form hydroxides, SO 4 2- With Ca 2+ Calcium sulfate is generated; the hydroxide and calcium sulfate generated in the neutralization process are precipitated through the inclined tube sedimentation tank, and the supernatant is discharged after the test reaches the standard, and the sediment is discharged into the sludge tank.

[0019] Example 2

[0020] As shown in the figure, add Cr by weight to the chromium-containing cleaning water 6+ 3.5 times of sodium metabisulfite, the Cr 6+ Reduced to Cr 3+; Then use a laminated filter to remove the larger particles of impurities; then use a PP filter element to filter to remove tiny particles above 5μ; then use a high-pressure pump to increase the pressure to make the pressure greater than the osmotic pressure, and enter the reverse osmosis Treatment, reverse osmosis treatment adopts a neutral anti-pollution reverse osmosis membrane to remove the metal ions and produce RO water; finally, the pH value of the RO water is adjusted to 6.8 with sodium hydroxide, which is the reuse water. After testing, its conductivity is 125μ, and the salt rejection rate is 95%. The reused water is used in the electroplating cleaning process and can replace clean tap water. After calculation, the recovery rate of water is 72%.

[0021] The concentrated water produced by reverse osmosis is neutralized with calcium oxide to adjust its acidity to near neutrality, and at the same time, the metal ions and -OH in it can form hydroxides, SO 4 2- With Ca 2+ Calcium sulfate is generated; the hydroxide and calcium sulfate generated in the neutralization process are precipitated through the inclined tube sedimentation tank, and the supernatant is discharged after the test reaches the standard, and the sediment is discharged into the sludge tank.