Method for recovering nickel and removing impurity from nickel-plated wastewater

Abstract

This invention involvess a process for recovering nickel and removing impurities from nickelizing wastewater, which comprises the steps of: a. directing the rinsing water for electronickelling into an ion-exchanger or a reverse osmosis device to produce a concentrated solution of metallic ions; b. directing the process a wherein said concentrated solution into a 3-dimensional electrochemical reactor for electrolysis, so that the impurity metallic ions can be removed from the solution and deposit on the surface of the cathode, thus obtaining a pure concentrated solution of nickel ions. This invention can recover nickel and remove impurities from the rinsing water for electronickelling, largely reducing the concentration of impurity metallic ions in the solution. At the same time, since the impurity metallic ions deposit on the surface of the cathode, they can be recovered. By adopting carbon fibers or foam metals or the two in combination as the cathode, the reaction has a high rate with low energy consumption. Last but not the least, this invention needs no auxiliary and produces no chemical contaminant, and the water can be recovered and recycled, thus possessing good economic performance.

Description

technical field [0001] The invention relates to a water pollution control technology, in particular to a method for recovering nickel from nickel-plating wastewater and removing impurities in heavy metal wastewater treatment. Background technique [0002] In the nickel plating industry, it is necessary to recover the nickel ions present in the nickel plating rinse water. On the one hand, this is the need for environmental protection, and on the other hand, because nickel is a precious metal, it has great economic value after recycling. However, in the nickel plating process, sometimes there is a copper plating process, so in this case, the electroplating rinse water will contain both copper ions and nickel ions. When concentrated by ordinary ion exchange or reverse osmosis When nickel ions are recovered, copper ions are also concentrated and recovered together, which become impurities and affect the quality of recovered nickel. In order to remove copper ions, impurities su...

AI Technical Summary

Problems solved by technology

However, in the nickel plating process, sometimes there is a copper plating process, so in this case, the electroplating rinse water will contain both copper ions and nickel ions. When concentrated by ordinary ion exchange or reverse osmosis When nickel ions are recovered, copper ions are also concentrated and recovered together, becoming impurities in it, affecting the quality of recovered nickel

In order to remove copper ions, impurities such as copper ions can be precipitated by precipitation separation, and then filtered and separated, but this method is costly and cumbersome and inconvenient to operate

The method of using ordinary electrochemical reactors is not completely separated, and the concentration of impurities such as copper ions cannot be reduced to a very low level. The concentration of residual copper ions is still large enough to become impurities for nickel recovery.

Chinese patent CN1100153A provides a method for removing copper from the nickel electrolysis anolyte. The method adopts the method of adding nickel sulfide to the anolyte, so that the copper ions in the solution are separated by forming copper sulfide precipitates. This method cannot be directly purified. While recovering copper from the nickel electrolyte, the resulting copper sulfide precipitate needs to be further processed

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