Metal Finishing Guide Book

2011-2012 Surface Finishing Guidebook

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Page 375 of 707

Figure 5: In traditional discontinuous operation, long-life, sulfate-free processes reduce operation cost. Between the three available continuous technologies, ENfinity® SteadyState offers the lowest operation cost. incremental steps. The volume of concentrates is not only significantly less than "Bleed & Feed," but surprisingly, also less than electrodialysis in operation. Amongst the three available technologies for continuous EN operation, ENfinity® SteadyState is the lowest-waste alternative. The ENfinity® SteadyState equipment only uses components approved and long-term tested for operation with EN. Besides controllers for nickel content, pH, and temperature, this is a density sensor that has already used for electrodial- ysis before. The unit differentiates between replenishment to compensate for depo- sition and demand for make up chemistry due to dilution. By additionally moni- toring the bath volume and automatic water feed, evaporation is compensated. The SPS controls all equipment components and collects all data for documentation. With at least the same degree of automatization compared to latest generation electrodialysis equipment, the investment for SteadyState is only a fraction. As only physical methods are used, reliability is high. No electricity is consumed for elec- trodialysis. While typically electrodialysis starts to become reasonable in cost above 2000 kg of annual nickel deposition, the limit for SteadyState is about 1000 kg nickel. While electrodialysis equipment needs to "grow" with higher nickel con- sumption, the SteadyState equipment can handle any volume as pump dimen- sioning does not significantly impact on investment cost. With increasing nick- el consumption, the investment cost per gram of deposited nickel declines in a 374

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