Case Study · Nickel Electroplating
All Brite: nickel rinse recycle without pH adjustment.
Treatability test on nickel rinse water from All Brite, with the objective of developing a recycle treatment procedure simple enough that no pH probe or caustic metering pump would be required. Powell Water E-Cell treatment at two power levels; Caro Labs analysis confirmed the lower-power configuration was sufficient.
The sample
All Brite personnel provided NEAT with two five-gallon containers of nickel rinse water taken from the rinse tank. The shop noted there were some contamination concerns in the rinse water but that the sample was representative of normal nickel rinse operations.
The raw water showed some whitish colouration but no settled sludge in the effluent and no settlement to the bottom of the pail prior to treatment. Initial pH was 6.51.
The objective
The primary objective wasn't just to treat the water — it was to develop a treatment procedure simple enough to install at All Brite without requiring a pH probe and caustic metering pump. If the nickel rinse water could be E-Cell treated without pH adjustment, the resulting equipment set would be substantially simpler and cheaper to maintain.
The treatment
The first 50% of the five-gallon sample was run through the E-Cell at four-chamber configuration, 27V x 20A at approximately 65% power. The treated water and floc flowed over the weir as expected — clear water with dark green to black floc that precipitated very quickly.
The second 50% was run at four-chamber configuration, 50V x 25A at full power. The treated water was still clear with the same dark floc, but a yellowish tinge appeared in the water — an indication of excess ferric being introduced. The 100% power setting was overshooting; the 65% power treatment was sufficient.
Results
Caro Labs in Kelowna analyzed one raw water and two treated water samples for nickel concentration. The results confirmed that E-Cell treatment without pH adjustment is sufficient for this nickel rinse stream, and that the four-chamber configuration at 65% power is the right operating point — high enough for complete treatment, low enough to avoid overshooting.
For All Brite, the practical implication is a simpler installation: no pH probe, no caustic feed pump, no chemical inventory. The treated water is suitable for recycle back to the nickel rinse tanks, reducing the shop's water consumption and discharge volume.
The full process flow chart is available as a PDF download.