Abstract:

CCR was experiencing persistent lacy copper and accelerated weld corrosion in its tankhouse, driving frequent cathode rewelding (every 3-4 years) and elevated repair costs. A contributing factor was the age and condition of the stainless steel sheets in service, which had been in operation for approximately 20 years.

To address these issues, EPCM executed a phased stainless steel sheet renewal program over a five-year period, replacing approximately 75,000 sheets while re-using existing copper hanger bars. The program was structured to minimize disruption to operations while systematically upgrading the sheet population and restoring consistent plating conditions.

Following implementation, CCR observed measurable improvements in both product quality and maintenance performance. Cathode weld life increased substantially, with welds lasting more than 10 years. Copper plating quality improved and lacy copper occurrences decreased. Maintenance outcomes also improved: repair costs were reduced, repair frequency extended to approximately five years, and overall machine performance increased due to reduced rework and improved stability in cathode handling.

After approximately 10 years of service, lacy copper began to return, indicating the need for continued monitoring and a deeper evaluation of the remaining contributors beyond sheet condition alone. Targeted studies were performed to identify the drivers of the recurrence and to develop practical solutions that dramatically decreased lacy copper.

This presentation summarizes the original problem, the planning and execution of a large-scale sheet replacement strategy, the operational results achieved, and the lessons learned from long-term performance and recurrence. The case study highlights the value of life-cycle planning for starter sheets and the importance of coupling capital renewal with follow-up operational diagnostics to sustain plating quality over time.

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Mr. Bryan MacMillan