A new coating option for equipment structures bonds with corroded surfaces to create an alloy barrier that is said to prevent corrosion for decades.
In mines, quarries, and aggregate bulk processing, large steel structures such as hoppers that are used to store and dispense vast volumes of stone, sand and gravel are often subjected to abrasion, moisture, and salt deposits, which can accelerate corrosion.
Once corrosion starts, often through a breach in traditional barrier-type coatings such as epoxies or polyurethanes, the coating can act like a greenhouse, trapping water, oxygen, and other corrosion promoters. This allows the corrosion to spread quickly under the coating itself, which is difficult to inspect, and can lead to failure and costly premature replacement. For these reasons, such coatings are typically reapplied at a additional cost in downtime, surface preparation, and coating application.
A new type of coating is said to offer extended corrosion and abrasion protection, while providing rapid turnaround with minimal surface preparation. Unlike traditional coatings, the product bonds best with corroded surfaces – so much so that flash rust is often intentionally allowed to form prior to application – to create an alloy barrier that can prevent corrosion for decades. The coating can be applied to equipment with pitting and is safe for application in enclosed or confined areas.
The hopper corrosion resulted from a very corrosive, moist, salty service environment. The hopper stores iron ore, accompanied by large amounts of natural salts, mined from deep underground. Condensation from varying temperatures throughout the year is also present.
To address these issues, the mine turned to SPI Performance Coatings, a European distributor, and EonCoat, a spray applied inorganic coating from the Raleigh, N.C.-based company. The coating is actually a chemically bonded phosphate ceramic (CBPC), one of the first of a new category of coatings designed to stop corrosion, ease application, and reduce downtime.
Source: Randall & Reilly/ Aggman
