China Banknote Printing and Minting Corporation :Treatment of Nickel plated Steel Electroplating Wastewater

China

In recent years, the discharge of wastewater generated from the production of nickel-plated steel products has remained at a high level.Upholding the philosophy of global ecological conservation, China Banknote Printing and Minting Corporation Limited devotes itself to the treatment of Nickel plated Steel electroplating wastewater and fulfills the mission of green development through technological innovation.
The unique color and luster of circulating coins are achieved via the Nickel plated Steel (NBS) plating process, whose core electroplating procedure generates wastewater laden with nickel heavy metal. Nickel ions (Ni²⁺), a Class I heavy metal pollutant, feature acute toxicity, chronic toxic effects and strong allergenicity. They readily persist in water and soil environments and bioaccumulate through food chains, posing potential hazards to ecosystems and human health. Accordingly, stable compliant discharge of treated wastewater stands as the core treatment objective.

(1) Complex Breaking & Decomposition
Aminosulfonic acid complexes in wastewater inhibit the precipitation of nickel hydroxide. After comparative reagent screening, sodium hypochlorite is selected as the complex breaking agent. It decomposes metallic complexes while oxidizing organic matter to reduce effluent chemical oxygen demand (COD), with outstanding economic efficiency, operational safety and usability, paving the way for subsequent treatment procedures.

(2) Targeted Heavy Metal Removal
On the basis of conventional flocculation and sedimentation, heavy metal chelating agents are dosed to rapidly react with nickel ions and form stable, water-insoluble macromolecular chelates. The generated flocs are bulky with fast sedimentation and dewatering performance, low non-toxic sludge output and zero secondary pollution, significantly improving nickel removal efficiency.

(3) Final Polishing Filtration
Ion exchange resin is installed at the terminal of the process to selectively adsorb divalent heavy metal ions, further lowering influent nickel concentration by 1/3 to 1/2 and forming the final safeguard for compliant effluent discharge.

Within more than ten hours, this combined process reduces wastewater nickel concentration from an initial level of 2–3 mg/L to below 0.1 mg/L, delivering a 20–30-fold concentration reduction and consistently stabilizing effluent quality within regulatory discharge limits.

An innovative three-stage progressive treatment system of complex breaking – chelating precipitation – resin polishing filtration is developed, customized for the distinctive water quality characteristics of complex-bound nickel in Nickel plated Steel electroplating wastewater. Compared with conventional universal heavy metal wastewater treatment technologies, the system boasts superior targeting performance and higher pollutant removal efficiency.
The synergistic advantages of the combined process are prominent: sodium hypochlorite simultaneously decomposes metal complexes and degrades COD; heavy metal chelating agents realize targeted deep nickel removal; terminal ion exchange resin ensures stable compliant effluent. The synergy of three processes breaks through the limitations of incomplete pollutant removal and volatile effluent quality associated with standalone single treatment technologies.
Balancing high treatment efficiency and economic viability, the integrated process features compact workflow, easy operation, low sludge production and no secondary pollution. It addresses the drawbacks of high energy consumption and excessive sludge output in traditional processes and strikes an optimal balance between environmental benefits and operational costs.

This project overcomes key technical challenges in Nickel plated Steel electroplating wastewater treatment and develops a mature, high-efficiency and replicable integrated treatment solution. It provides standardized technical references for the treatment of similar heavy-metal-containing electroplating wastewater and drives technological upgrading of environmental governance across the industry.

Practicing the green development philosophy and aligning with global ecological conservation and sustainable development trends, the project coordinates industrial production and environmental protection via technological innovation and facilitates the achievement of industrial pollution and carbon reduction targets.
Effective treatment of heavy metal wastewater mitigates water and soil pollution, conserves biodiversity and consolidates regional ecological security, underpinning long-term sustainable ecological development.