Research On The Mechanical Properties And Grinding Mechanism Of The Cement Clinker

Based on the current status that the research on grinding mechanism falls behind the application and restricts the improvement of grinding efficiency and energy efficiency, grinding processes of single cement clinker particle were studied, in the conditions of room temperature, high temperature, low temperature, etc. As a result, the relationship between grinding conditions and grinding behavior was verified. In the meanwhile, grinding mechanism at different temperatures was also ascertained. The new approach of low-power grinding was explored according to the results.During the experiment, physical and mechanical indexes of cement clinker at room temperature were determined by micro Vickers durometer and solid materials dynamic elastic properties tester. The impact experiment was carried out under different impact angles using low temperature experimental equipment. Influences of impact angles on impact curve, acoustic emission signal, peak impact force and impact indentation morphology were systematically studied, at room temperatures.Cement clinker samples were prepared in the laboratory and mechanical experiments were carried out under different temperatures during the cooling process. Influences of the high temperature on load-displacement curve, compressive strength, elastic modulus of cement clinker were systematically studied, using high temperature mechanical testing instrument. By low temperature mechanical testing instrument, effects of the temperature on load-displacement curve, peak force and grinding power consumption were discussed. According to the method of Realistic Failure Process Analysis, uniaxial compression tests and shear tests were simulated through RFPA2D. The results show as follows:(1) Vickers hardness of cement clinker is 5.191GPa. Fracture toughness is 0.817MPa·m1/2. Elastic modulus is 27.06GPa. There is not indentation crack of brittle materials in the Vickers indentation morphology of the clinker. In conclusion, cement clinker belongs to quasi-brittle materials. When impact angle is 75°, the peak impact force is minimal value. Impact grinding experiment shows that: with the impact angle increasing, the average impact peak force is decreased. So 75°is optimal grinding angle of cement clinker.(2) High temperature experiment shows that the hardening phenomenon of the clinker becomes obvious with decrease of the temperature. With the decrease of the temperature, the elastic modulus and compression strength of cement clinker increase. Elastic modulus increase greatly when the temperature is lower than 1000℃. The compressive strength of cement clinker reduces sharply from 1100℃to 800℃. Low temperature experiment shows that when the temperature is higher than -40℃, with temperature decreasing, the peak force of cement clinker increases, but when temperature is lower than -40℃, the peak force decreases as the temperature drop. It can be considered that -40℃is brittle transition temperature of cement clinker, because of the changes of load-displacement curve of the whole process, peak force and grinding power consumption with temperature. Energy conservation can be carried out when grinding is processed below about -40 degrees.(3) The simulation results of RFPA2D system reproduce the failure process of materials, which include elastic deformation, crack initiation and expansion, unstable propagation of cracks. The results show that the grinding mechanism of the numerical simulation test and the real test is consistent.