Method for recovering nickel salts in nickel-electroplating waste water

Abstract

The invention belongs to the technical field of industrial waste water treatment, in particular to a method for recovering nickel salts in nickel-electroplating waste water. Aiming at the defects of larger investment and high operation cost of the prior nickel-electroplating waste water treatment, the invention provides the method for recovering the nickel salts in the nickel-electroplating waste water, which has low investment, simple operation and low cost, and ensures that recovered nickel salts can be directly reused for a nickel-electroplating tank. The method comprises the following steps: (1) alkali is added to the nickel-electroplating waste water; (2) the nickel-electroplating waste water treated by the alkali flows into a precipitator for precipitation; through the precipitation, the nickel-electroplating waste water containing the precipitate which is nickel salts is inputted into a press filter for nickel salt press filtering; the obtained precipitate nickel salts are washed with clear water for a plurality of times so that the obtain pure nickel salts which can be directly reused for the electroplating nickel tank is obtained; and (3) supernatant fluid flows into a neutralization pond for neutralization.

Description

technical field [0001] The invention belongs to the technical field of industrial waste water treatment, in particular to a method for recovering nickel salt in nickel electroplating waste water. Background technique [0002] Existing treatment methods for nickel-containing electroplating wastewater include reverse osmosis membrane method and ion exchange method, wherein: [0003] (1) The nickel salt is recovered by the reverse osmosis membrane method, which can concentrate the nickel concentration in the nickel-containing solution by 10 to 20 times, and the waste water becomes deionized water, which can be reused for liquid preparation and cleaning. But this method makes the nickel concentration still less than 1g / l, because the concentration is too low, so it cannot be reused in the electroplating nickel tank; and the cost of using the reverse osmosis membrane method is as high as more than 8 yuan / ton, and the one-time investment is also large, so Treating nickel-containi...

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Problems solved by technology

[0006] The present invention is aimed at the vast majority of electroplating plants in the existing electroplating nickel wastewater treatment, which directly discharges nickel-containing wastewater into the comprehensive electroplating wastewater pool for treatment. The treatment of electroplating sludge is prone to secondary pollution. In addition, it is recovered by reverse osmosis membrane method. The cost of nickel salt treatment is high, and the one-time investment is also large. The one-time investment of nickel salt recovery by ion exchange method is relatively large, and the operating cost is high. Insufficiency, a kind of one-time investment is not large, the operation is simple, the cost is low, and the recovered nickel A kind of nickel salt recovery method in the electroplating nickel waste water that salt can be directly used in the nickel electroplating bath

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