Wear in cone crusher chambers

Sammanfattning: Cone crushers are widely used in the mining and aggregates industries to reduce the size of blasted rock. A cone crusher consists of a fixed conic liner called concave and inside it a smaller moving liner called mantle. The mantle is suspended on an eccentrically rotating shaft. As the eccentric is turned, rock particles fed to the crusher will be squeezed and crushed between the mantle and concave. The crushing process is governed by the geometry of the crusher liners. Previous research has made it possible to model the crushing process for a given set of liners and feed rock material. This model has made it possible to optimise the geometry of the crushing chamber. A problem however is that due to wear the crusher geometry and performance will change and possibly suffer. For this reason it is desirable to be able to simulate not only the crushing process for a given crusher, but also the wear and change of performance over time. A model for this purpose is presented. The cone crusher model comprises flow, breakage, power draw, hydraulic pressure and wear. The material used in rock crusher wear parts is austenitic manganese steel, a material well known for its work hardening capability. It has been a common conception in the mining and aggregates industry that the work hardening increases as the crushing pressure against the liner increases. To verify this, hardness tests were performed on two mantles that were cut and grinded. Liners used to crush two different materials, granite and highly abrasive quartzite, were studied. The tests reveal that there is no variation in obtained hardness depending on crushing pressure or rock material for the studied application. The crusher model has two model parameters which need to be validated. A study was conducted in a quarry where operating conditions were tracked during the lifetime of the liners. Operating parameters are predicted with acceptable accuracy, although the crusher was run under inconsistent conditions. An important question is whether model parameters remain valid as liners are worn. The simulation results show that they do. The crusher model is useful to engineers developing new crusher liners, and for selecting an appropriate liner for a certain crushing application.