Electrochemical obtaining of nickel hydroxide from nickel plating waste water for application in the alkali secondary cells
V.L. Kovalenko, V.A. Kotok, V.V. Malyshev
Section: Ecologization of industry
The rinsing and wastewater of the plating industry, containing the heavy metal cations, are the source of environmental pollution. Nickel cushions have a strong biological hazard. At the same time, up to 30% of nickel compounds spent on nickel plating are irretrievably lost to the rinsing water. Purification of the rinsing and wastewater from heavy metal cations is expansive. It’s economical effective to develop the methods of local treatment of plating rinsing water with the recovery of the heavy metals in the easy utilizing forms. The hydroxide is the most perspective for nickel, which, if it has high electrochemical activity, can be used for alkaline secondary cell production. The method of electrochemical synthesis of the nickel hydroxide in the slit diaphragm electrolyzer from the rinsing water of bright nickel plating has been proposed. The treatment of rinsing water of the bright nickel plating for surfactants recovery has been made. The samples of nickel hydroxide, obtained from treated and untreated rinsing water, have been studied by XRD, voltammogram and charge-discharge cycling in the secondary cell regime. The comparative analysis shows that even the nickel hydroxide sample, obtained from untreated rinsing water, can be used as an active substance of the positive electrode of alkaline secondary cells. This sample’s specific capacity is 142 mА•h/g with cost is 4 $/kg (in comparison with 182 mА•h/g and 18-22 $/kg for industrial sample). It was detected that the nickel hydroxide sample, obtained from the rinsing water of bright nickel plating after purification from surfactant by bubble-film extraction, has the highest parameters. In this case specific capacity is 194 mА•h/g compared 182 mА•h/g for the industrial sample produced «Boсhemiе» (Czechia).
ISSN 1995-4301
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