Full definition
Polyurethane (PU) elastomers are increasingly utilized in the mining industry due to their remarkable performance characteristics, particularly in terms of abrasion resistance and load-bearing capacity. Cast polyurethane components typically exhibit abrasion resistance that is 3 to 10 times greater than that of natural rubber in fine-particle sliding wear scenarios. This is crucial in mining applications, where equipment and components are subjected to extreme conditions and abrasive materials. The hardness of PU used in these settings usually ranges from 85 to 95 Shore A, making it suitable for a variety of wear applications in mining and mineral processing.
Key applications of polyurethane in mining include modular screen panels designed for vibrating screens, which offer a lifespan that is three to five times longer than traditional woven wire options, in addition to features like self-cleaning capabilities and noise reduction. Cyclone components, including vortex finders and apex liners, also benefit from PU's durability. In slurry transportation, internal PU linings for pipes can last five to ten times longer than rubber alternatives, significantly reducing maintenance costs and downtime. Other applications include conveyor components such as scrapers and skirting, pump linings, impellers for fine abrasive slurries, and flotation cell components like stators and impellers.
There are two main types of polyurethane used in mining: polyester-based AU, which provides the best abrasion resistance, and polyether-based EU, which offers superior hydrolysis resistance, making it ideal for wet mining applications. However, it is important to note that polyurethane does have limitations; it softens at temperatures above 80°C, is sensitive to hot water and steam, and exhibits lower impact absorption compared to natural rubber at low angles. Therefore, for applications involving heavy impact, natural rubber is often the preferred material. The processing of polyurethane involves casting from a liquid prepolymer combined with a curative, followed by curing in molds and post-curing at 100°C for 16 to 24 hours.