FLSmidth has released a new patent pending wear liner product, FerroCer® Impact, which helps mining companies reduce production downtime.
Helgi Gudbjartsson, Global Launch Manager, FLSmidth: Helgi.Gudbjartsson@flsmidth.com
As heavy bulk materials pass from station to station in a minerals processing plant, processing equipment is stretched to the limits of its capabilities. The wear rate of components, typically in chutes and hoppers is very high. The cost of replacing worn down consumables makes up a substantial proportion of the total maintenance expenses, so anything that can be done to reduce wear and increase equipment lifetime will have a significant impact on operating cost. The right choice of wear protection can contribute significantly to reducing maintenance costs and equipment downtime.
Current practice for wear protection usually involves wear liners or panels, which are bolted or welded onto the equipment. Different wear liners are applied in different situations, depending on factors such as type of ore, drop height, material lump-size distribution, and angle of impact. Each wear liner has its own advantages and disadvantages. Common types include hard-metal liners, heavy-duty rubber or rubber/ceramic composite liners, each with their own strength and weakness:
High in density, metallic wear liners are heavy – up to 40 percent heavier than ceramic. The hardest metals are particularly expensive and difficult to work with. Furthermore, they have significant limitations when operating in either of the temperature extremes. While hardness is reduced at higher temperatures, impact strength is reduced at lower temperatures.
Ceramic wear liners can be difficult to attach to existing chute work, requiring special adhesives or suspension within an elastomeric matrix. They can also detach easily from the substrate if surface preparation is poor or if the adhesives and elastomers are incorrectly prepared. They are extremely difficult to cut and cannot be bent or formed.
Such challenges have had a significant impact on maintenance procedures and costs. A general issue facing the industry is the loss in production time because of wear liners frequently needing to be replaced and the time it takes to install new liners.
A typical example could be for material of a common ore, such as gold, copper or nickel, with a hard impact velocity of more than 7 m/s. In such a situation, the wear liner may have an average lifetime of one or two months at most. The replacement procedure can take a whole shift, putting the process flow on pause for several hours resulting in significant production losses.
With units of wear liners weighing anywhere between 20 and 40 kg apiece, safety is also a concern. A special lifting mechanism is often needed in addition to the scaffolding, allowing maintenance personnel to safely access the installation points.
Composite structure of steel and ceramic components
FLSmidth has developed a wear liner solution specifically to address the challenges of operating crushing equipment, particularly related to wear liner longevity and installation time as well as the safety of personnel involved.
A unique composite structure of steel and ceramic components, FerroCer® Impact provides the advantages of both ceramic and metallic materials. Combining the superior abrasion resistance of a ceramic with the strength, toughness and malleability of a metal, it handles hard and abrasive materials in medium to high impact applications.
Traditional metallic liners wear down too quickly and ceramic liners tend to crack or disintegrate. FerroCer Impact has been shown to increase wear resistance by a factor of up to 15 times compared with traditional wear solutions, depending on the ore type and application. This allows minerals processing plants to achieve a total cost of ownership less than half that of other liners.
FerroCer Impact panels are lighter and less bulky than traditional metallic liners. Each panel comprises a number of ceramic inserts enclosed within a matrix of cast metal. The matrix protects the more vulnerable side faces of the inserts and ensures that only the wear face of the ceramic is exposed to material impact.
The tapered geometry of the ceramic inserts and corresponding holes within the matrix act to wedge the inserts within the matrix and prevent material particles and fluids from causing them to be ejected from the matrix.
This design also enables the remaining wear life of the ceramic inserts to be visually assessed. As the exposed surface of the insert is progressively worn away, its area and face width increase. There is a direct correlation between an insert’s face width and height so that the one can be readily calculated from the other.