Erosive wear mechanisms of rubber pump lining materials in minerals processing applications

摘要

Erosive slurry wear occurs extensively throughout minerals processing equipment for slurry transport applications. Wear resistant materials are designed to prolong the life of equipment used to transport the slurry such as pumps, hoses, grinders, conveyor belts, screens, etc. In this study, the erosive wear mechanisms of rubber pump lining materials used in slurry pumps were explored at a structural level. The erosive wear mechanisms for rubber pump lining materials have not be extensively investigated in the literature. Arnold and Hutchings [1] were the pioneers in this field of tribology, however, a number of key areas for study remain. Although the wear mechanisms of rubber wear in slurry erosion are well documented in the literature, the chemical degradation of the rubber during this erosive wear has not been investigated. Furthermore, the viscoelastic properties of the rubber and their correlation with erosive wear have not been well documented. The approach to this study was to investigate four different rubber compounds used in slurry transport pumps and determine the wear mechanisms and their correlation with physical, viscoelastic and chemical properties of the rubbers. A slurry jet erosion test was used to investigate the wear rate of each compound under different variables. The samples were then chemically analysed using a Fourier Transfer Infra Red (FT-IR) Spectrometer to determine the extent of chemical change to the surface of the rubber during erosive wear testing. The physical properties of the rubber were tested using conventional test methods, whereas a Rubber Process Analyser 2000 (RPA2000) was used to determine the key viscoelastic properties. It was important to investigate these properties of the rubber compounds to determine which properties could be correlated with erosive wear. Through FT-IR analysis of heat aged samples of the rubber compounds, it was established that erosive slurry wear does not correlate with aging, however, heat aging influences the hardness, resilience and viscoelastic properties which increases the wear rate of the rubber compounds. The key findings from this study were that heat aging would increase the tan δ and hardness, and lower the resilience, hence, causing lower erosive wear resistance in all the rubbers. Tan δ, hardness and resilience could be correlated with erosive wear loss, the heat aging effect and the chemistry of the rubber compounds. The influence of the type of reinforcing filler and cure systems could also be correlated with erosive wear resistance. Rubbers with a high loading of reinforcing carbon black resulted in a low wear resistance in comparison to a high wear resistance for silica and silane filled rubber compounds. Tan δ was also correlated with the type of reinforcing filler used in the rubber chemistry. The significance of these findings is important for the future design of rubber compounds used in slurry erosion wear resistant pump liners. For a highly slurry erosion wear resistant pump liner, a high resilience, low tan δ and hardness (as are found in silica and silane reinforced rubber) would be required.