Abrasion protection in the toughest environments

Harsh operational environments and tough heavy-duty surface and underground mining processes can lead to the early failure of slurry pumps used in the transportation of abrasive solids in large volumes.

Despite significant progress in the mechanical design of slurry pumps, they are still extremely susceptible to erosion, with abrasion wear being one of the main threats to the longevity and performance of these pumps. When a critical slurry pump goes off-line unexpectedly, a large mine can experience an exponential loss in revenue.

Belzona metal and rubber repair composites, coatings and linings are specifically formulated to repair and protect equipment in the mining and quarrying industry and Belzona's abrasion-resistant protective coating products are specifically designed to slow down the abrasion process in pumps.

Specifying the coating materials for slurry pumping applications is not a standard procedure and must account for all variable characteristics, such as the type and speed of the pump and the nature of the solids.

According to a Belzona technical service engineer, even though handling abrasive fluids presents a tremendous challenge to any protective material, a carefully selected abrasion-resistant coating can reduce impact wear effects, extend the life of a pump and optimise the overall performance of the pumping process.

Belzona cites the example of an Australian nickel and cobalt producer that required a reliable restoration and efficiency enhancement solution for its refinery centrifugal vertical slurry pumps. The nickel ore is dried, ground, roasted and leached in an ammonia solution to extract the nickel and cobalt in the refinery’s processing plant. The nickel and cobalt are then separated and further refined in the metal refining area.

One of the refinery’s most critical pumps is the 12” Hazelton VDS slurry pump used to extract and transport ore from the primary tailing sump and distribute it to the process units for refinement. The pump runs continuously, 24/7 and, as a result of extreme wear, a second pump is required to be constantly available as a standby unit and a third pump is used as a spare rotatable unit.

After 2 500 hours of continuous operation, the operational unit is replaced by the second unit, which is then replaced by the third spare pump and the pump that has been removed is stripped and inspected. “An uncoated volute was put into service in 2013, and was almost irreparable after 5 000 hours," explained a Rezitech Services manager and Belzona authorised distributor in Australia.

A set of four erosion and corrosion-resistant Belzona composite repair materials and protective coatings were used to fulfil the imperative abrasion and temperature resistance requirements of the nickel cobalt operation's pumps. Worn cutwaters were repaired with Belzona 1311, a paste-grade ceramic-filled epoxy-based repair composite for rebuilding and re-profiling of damaged areas. Once cured, the cutwaters were shaped to the required dimensions using an angular grinder.

Belzona 1321, a ceramic-filled epoxy coating designed to protect against moderate abrasion, was applied to the entire casing internals as a priming coat, while Belzona 1812, an epoxy-based composite material formulated with highly hard ceramic aggregates closely packed in a polymeric binder, was then applied.

A final layer of Belzona 1391, specifically designed for equipment that operates at high temperatures under immersion, was also applied throughout the pump internals to provide additional heat resistance. "From start to finish, the application lasted less than a week and with simplified application techniques, the client was able to avoid replacement costs in excess of approximately $15 000,” said a Belzona technical engineer.

“The repair solution cost approximately half of this amount and prevented revenue loss due to downtime in the amount of $77 000 per hour."