Contamination Control
in Mining Process Plants

Introduction

In the harsh, high-temperature environment of a sinter plant, where iron ore, limestone, and coke breeze are fused into a porous sintered product, equipment faces constant exposure to contaminants. Among the most critical pieces of equipment in this process are steel belt gearboxes, which support the continuous operation of sintering machines. However, these gearboxes are under siege by abrasive particles—especially chromium-rich dust—that compromise their performance and longevity. Fortunately, advances in contamination control are redefining what’s possible in gearbox reliability and lifespan.

The Challenge

Sinter plants operate under some of the most extreme conditions in the metallurgical sector. Fine sinter dust infiltrates even well-sealed systems, leading to particle-induced abrasion and fatigue. For gearbox systems, this means:

• Accelerated wear: Chromium and other hard particles cause three-body abrasion that destroys gear surfaces.
• Seal degradation: Repeated exposure to fine dust wears down seals, allowing further ingress of contaminants.
• Increased maintenance: Regular oil changes, inspections, and component replacements become the norm.
• Operational disruptions: With new gearboxes costing over $270,000 and delivery timelines exceeding a year, unscheduled failures wreak havoc on plant uptime and budget forecasting.

These risks are compounded by environmental and safety concerns. Dust exposure is a health hazard, necessitating stringent controls to ensure workplace safety.

The Breakthrough

To tackle these escalating issues, FMS Africa collaborated with @RMFSystems to implement a comprehensive contamination control strategy at a major South African sinter plant. Central to this strategy was the installation of the Offline Filtration Unit (OLUHS), which included:

• Glass fiber filter elements: For deep filtration of sub-micron particles.
• Contamination Monitoring Sensor (CMS): Tracks particle load in real time.
• Oil Quality Sensor (OQS): Measures oil degradation and performance.
• Desiccant breathers (ACM61 & IsoLogic®): Block moisture and airborne contaminants.
• 3D Bullseye®: A visual oil monitoring tool to assess lubricant health.

Additional infrastructure included drain port adapters and breather adapter kits for seamless integration. These technologies were installed on two critical gearboxes responsible for steel belt movement—core to the sintering process.

The Results

The improvements were rapid and measurable:

• Dramatic Oil Cleanliness Gains: Within 7 days, ISO 4406 cleanliness improved from 23/22/19 to 15/13/10, significantly below the industry target of 18/16/13.
• Iron Wear Reduction: Particle count analysis showed a 2.5x decrease in iron particles, meaning reduced internal wear and smoother operation.
• Extended Gearbox Lifespan: Projected equipment life doubled, slashing the annual operating cost per gearbox from $18,000 to $9,000.

These benefits directly enhanced plant reliability, reduced the frequency of maintenance shutdowns, and ensured consistent product quality.

Financial Payoff

The upfront investment of $26,000 for two gearboxes paid off quickly:

• Payback Period: 17 months
• Annual Cost Avoidance: $18,000 total across both gearboxes
• Internal Rate of Return (IRR): Over 200%
• Net Present Value (NPV) over 5 years: $34,751

These financial metrics underscore the value of predictive maintenance and smart filtration as strategic business decisions, not just technical upgrades.

Conclusion

Contamination control in steel plants is more than a maintenance concern—it’s a performance and profit driver. With the right combination of filtration technology and monitoring tools, gearboxes can operate cleaner, longer, and more efficiently. As the FMS Africa case shows, investing in oil cleanliness isn’t just good engineering—it’s smart business.

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