Mechanism And Experimental Study Of Sepiolite Crushing Under Pressure-varying Conditions

As a common non-metallic clay mineral,sepiolite has high application value in life and industry.At present,sepiolite powders is mainly processed by mechanical crushing methods.However,crushing minerals by these methods not only consumes high energy,but its fiber structure of sepiolite is often destroyed by extrusion and friction,which seriously affects the performance of mineral powder.In order to solve this issue,this dissertation proposes a new method of crushing sepiolite,namely,pressure-varying crushing method.First,a rotating closed container is designed.Then,pressurizing the ore with water vapor is conducted.Finally,sepiolite powder is obtained through the rapid pressure relief device and pressure relief channel.This dissertation mainly focuses on the following five aspects:(1)The physical characteristics of sepiolite are measured.The density,moisture content,tensile and compressive strength,Poisson’s ratio and elastic modulus of sepiolite are measured,and the fiber structure of sepiolite is observed.The detection of physical properties of sepiolite will provide indispensable data for theoretical analysis and simulation of the pressure-varying crushing method of sepiolite.(2)Study of the sepiolite crushing mechanism under pressure-varying conditions.Based on the superior water absorption characteristics of sepiolite,the Griffith strength theory is revised in the high pressure steam environment.Using ABAQUS cohesive unit to simulate the expansion of the internal fractures in the sepiolite under the high pressure steam environment.Based on these simulation results,the influences of the changes of the original fracture angle and horizontal stress inside the sepiolite on the fracture propagation of the sepiolite under the high pressure steam environment is analyzed.(3)Simulation of the crushing process.The crushing process of sepiolite under pressure-varying crushing method is simulated by RFPA(2d)software,and and the differences between this method and the extrusion method are discussed.(4)Experiments and analysis of pressure-varying crushing method of sepiolite.A workbench is built to verify the practical application of the " sepiolite breaking under pressure-varying condition ".The crushing of sepiolite under the pressure value of0.1MPa-0.6MPa is completed(take a value every 0.1MPa).Then the broken sepiolite particles were observed by SEM to obtain their fiber structure characteristics.Theoretical analysis and experimental results show that the use of pressure varying crushing method to crush sepiolite not only reduces the energy consumption in the crushing process,but has a good protective effect on the fiber structure of sepiolite.The proportion of micron-sized particles after crushing increases significantly as the increase of the set pressure value.