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topic 11980

Bright Nickel forms dark green crystals and dark brown liquid



I'm facing bright nickel problem. It's new bright nickel solution after 20 weeks bright nickel forms dark green crystals & drank brown liquid. We have also observed the solution, when left in the tank does decrease in quantity by itself. I have try to boil the nickel solution all green crystals have dissolve at 70 C. But after few mins it forms very small green crystals. Also nickel solution is decreasing when I'm not using the bath. pH of nickel solution is 3.8. Can anyone help me?

Dipen Pattni
Dipen Pattni
jeweler/goldsmith - Dar-Es-Salaam, Tanzania


If crystals are forming it is because there is too much nickel to stay in solution at that temperature. So: either the temperature is too low; or the nickel content is too high; or there is another metal in solution which, by the common ion effect, is limiting the amount of nickel that the solution can hold. I'd analyze for iron.

Ted Mooney, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey


Although I have little experience with bright nickel, I can tell you that the volume of the bath will naturally decrease over time due to evaporation of the water, especially if it sits at operating temperature. You should check your nickel concentration. The dark green crystals may be nickel sulphate that precipitate somewhere around 90 to 100 gram/liter nickel. I can't explain the dark brown liquid and can only suggest you get in touch with the supplier of your bright bath chemicals.

Good luck,

Don Piett
INCO Ltd - Thompson, Mb, Canada


I just like to answer if anybody got like this problem it can solve after reading this answer.

First why it forms dark green crystals in bright nickel b'coz of evaporation of the water I just heat a solution and added DI water where the mark was done before.

Secondly dark brown liquid b'ocz of dustand other metals come inside after carbon filtering it'll remove that dark brown liquid and clear the solution and add relcement brightener as per data sheet.

It worked fine like before.

Dipen Pattni
Dipen Pattni
jeweler/goldsmith - Dar-Es-Salaam, Tanzania

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