摘要 |
A method for the recycle treatment of nickel plating waste water, in order to efficiently recover the nickel components from waste water which has been used for the washing of nickel plated products in a form re-usable as a nickel plating solution as such, wherein the nickel plating waste water is mixed with an aqueous alkaline component so as to remove, by precipitation in the form of hydroxides, contaminating metal ions other than nickel; the filtrate so obtained is treated through an ion exchange process so as to obtain an aqueous solution of nickel salts containing excess free sulfuric acid, a portion of which is then treated with alkali so as to precipitate nickel hydroxide which is separated in the form of nickel hydroxide through filtration by means of a centrifuge; the nickel hydroxide so obtained is then added to the rest of the aqueous nickel salt solution for neutralization with the free sulfuric acid contained therein to form nickel sulfate; and the free sulfuric acid is then removed so as to obtain a highly concentrated nickel sulfate solution.
|