| Blast furnace slag is a high-temperature melt with high potential for waste heat recovery.Traditional blast furnace slag generally uses wet granulation process,which in addition to has the disadvantages of occupying land,waste heat resources are not effectively recovered,also to a certain extent will cause pollution to the environment,so the research about its high value-added resource utilization becomes especially critical.Blast furnace slag gas quenching granulation process is a new treatment method,its principle is to use the powerful pneumatic force of high-speed airflow to complete the impact granulation of slag.Through this method,the quality of the slag particles can be guaranteed at the same time,but also to collect the heat absorbed by the airflow from the high temperature slag and the sensible heat of the slag,and the process without pollutants,so the gas quenching granulation process is a very promising treatment method.The blast furnace slag gas quenching granulation process is accompanied by two parts: the slag granulation stage and the slag solidification process,and the following contents are used to study the changes of the blast furnace slag gas quenching granulation process and the phase change law of slag solidification by numerical simulation of these two processes separately.In the granulation stage,multi-phase flow and heat transfer are involved,and the granulation mechanism is complex,and there are more factors affecting the granulation process.By analyzing the temperature field distribution and the slag phase distribution at0.9s,it was found that the two coincided to a high degree and the temperature field could be used to explain the slag phase field.Then,the simulation calculation of gas quenching granulation was carried out by changing the parameters of gas injection pressure,initial viscosity of slag and slag tank diameter individually,and the influence of different parameters on the temperature distribution and slag phase distribution in the gas quenching granulation process was obtained.In the process of solidification phase change of slag particles,first of all,a single working condition was simulated to obtain the corresponding temperature field,velocity field and liquid phase distribution,and it was found that the inward solidification rate of slag particles in each direction was different.The surface solidification time,complete solidification time and liquid phase rate of slag particles were analyzed to study the effect of cooling air velocity,initial temperature of slag particles,diameter of slag particles and other parameters on the solidification characteristics of slag particles.It was found that with the increase of cooling air speed,the initial temperature of slag particles and the diameter of slag particles decreased,the phase change solidification process of slag particles accelerated.Then,the simulation is verified by gas quenching and granulation experiments of quenched and tempered blast furnace slag.Comparing the experimental results of gas quenching granulation with the simulation results for each control parameter of gas pressure 0.5 MPa,slag tank diameter30 mm and initial viscosity of slag 0.6 Pa·s,it was found that the granulation flight trajectory of individual slag flow unit was radially moving away from the nozzle outlet,and its breakage period was 0.28 s,and the landing distance of slag was 5 ～ 13 m.The feasibility of the numerical simulation is verified,and the significance of the numerical simulation for gas quenching granulation experiments is confirmed based on the present simulation parameters and experimental conditions.Figure 36;Table 4;Reference 47... |
PDF Full Text Request