Understanding Alloy Performance Trends in Real Ores

Abstract

Research Problem and Context In heavy mineral processing infrastructure, ore transfer chutes are subjected to relentless abrasive sliding and low-angle kinetic impacts by high-tonnage particulate product streams. Sacrificial protective liners, typically specified from homogeneous quenched-and-tempered steels or multi phase high-chromium white cast irons (HCWCIs), display rapid deterioration rates in the field. Materials specifiers and mechanical asset engineers traditionally pre-screen candidate alloys using standard laboratory tests operating with benchmark quarry aggregates (such as basalt or granite) to forecast wear life. However, a systemic disparity exists between the optimistic alloy performance profiles predicted by standard laboratory models and the accelerated, premature wear rates documented in operating mining installations processing real ores. This contradiction stems from an unquantified limitation: standard quarry minerals do not accurately replicate the unique physical characteristics, high specific gravities, and brittle fragmentation transitions of true multi-component mining rocks. Consequently, relying on quarry rock proxies risks generating misleading alloy selection hierarchies, resulting in unexpected plant structural failures and costly unscheduled maintenance shutdowns. Methodology Overview This investigation evaluated the mechanical and metallurgical validity of laboratory quarry proxies by systematically comparing the wear rates and performance rankings of an established six-material alloy suite across both industrial and quarry minerals. Testing was executed using the Inner Circumference Abrasion Test (ICAT) apparatus operating in a sliding and low-angle impingement configuration (10-degree specimen tilt angle) at a controlled paddle tip velocity of 9 m/s, utilising a tightly sieved coarse fraction sizing of -8 mm +1 mm. The experimental matrix evaluated four geologically distinct rock types: standard commercial Basalt and Granite (quarry benchmarks), alongside real, high-competence Marandoo Iron Ore and heterogeneous Oyu Tolgoi Quartz Monzo diorite (QMD) ore (industrial benchmarks). Quantitative mass loss measurements were taken before and after each run to map cumulative mass to-volume loss and linear thickness reduction tracks (micrometres per hour) across five replicates. Following each primary test, a specialised dual-reinforced high-carbide white iron specimen (CB102) was isolated for microstructural comparative analysis. Qualitative surface diagnostics were conducted via high-vacuum Scanning Electron Microscopy (SEM) using a Hitachi TM3030. To isolate fundamental micro-mechanisms, four subsequent Very Short Duration (VSD) scratch mapping experiments were conducted using highly polished CB102 specimens across all four abrasive ore types to characterise immediate steady-state profile changes. Key Findings and Results The quantitative wear data revealed that the industrial ores were substantially more severe than their assumed quarry proxies, with QMD producing higher wear rates than granite for metallic materials, and iron ore producing higher wear rates than basalt across all tested materials. Material optimisation tracking demonstrated that for highly abrasive QMD and granite environments, sintered technical structural ceramic (CE45, 92% alumina) provided superior wear resistance. Conversely, in iron ore and basalt applications, the specialised micro-alloyed white iron (CB102) emerged as the most suitable material. SEM microstructural diagnostics elucidated the precise wear mechanisms driving these variations. In QMD environments, high-hardness quartz phases sheared directly through the matrix and the (𝐶𝑟,𝐹𝑒)7𝐶 eutectic carbides as if they offered equal resistance, though the harder Niobium Carbides (NbC) successfully resisted abrasion and protruded from the surface. Both carbide phases sustained extensive localised micro-cracking without complete fragmentation or pull-out. In contrast, basalt minerals lacked the hardness to cut the eutectic carbides, eroding only the softer matrix and leaving the flat carbide plateaus heavily recessed. Testing with iron ore revealed an intensely adhesive, "sticky" interface, masking over 95% of the metallic surface area. However, visible regions indicated an abrasive mechanism closely mirroring that of basalt, albeit with a less pronounced height contrast between the matrix and eutectic phases. Implications and Significance These results clearly demonstrate that standard construction quarry aggregates are fundamentally unsuitable standalone proxies for industrial mining ores due to severe misalignments in micro abrasive mechanics. Relying on standard testing without establishing strict mathematical correlation factors risks underestimating liner wear severity and may lead to poor material selection in mining infrastructure. For asset managers, this work establishes a clear material selection hierarchy: specifying structural ceramics to combat quartz-heavy gouging (QMD) and deploying micro alloyed white irons (NbC reinforced) to mitigate highly adhesive iron ore wear streams.