Efficient wastewater treatment in nickel refinery

Nickel production rate threatened by inadequate water treatment

Kemira’s expertise in water chemistry and water treatment was recently used by a nickel refinery struggling with its wastewater treatment. As a key supplier to the refinery, Kemira was asked to investigate and develop alternative treatment methods to ensure compliance with regulatory demands.

The conventional treatment method used by the refinery proved to be inefficient. In the process, all of the wastewaters were collected in one central thickener where cationic flocculant is added to assist in the separation process. As the production rates increased, the amount of wastewater grew as well, exceeding the refinery’s treatment capacity. If the levels of solids in the overflow surpass certain values, the nickel production would have to be decreased or even stopped, leading to significant financial losses for the refinery.

Keeping solids levels in compliance while increasing production rates

Kemira assessed the whole water treatment process and compared alternative anionic and nonionic polymers that could substitute the use of cationic flocculant. Application testing indicated that Kemira’s Superfloc anionic and nonionic polymers could achieve significantly improved separation results than the cationic product. Upon implementation of the new polymers on the full scale operation the total capacity of the waste treatment plant was increased. The nickel production increased without any negative impact to the water treatment process and the solids levels were within regulatory limits.