| Flash smelting is one of the dominant technologies for copper smelting production.The reaction shaft of the flash smelting furnace is the main place where smelting reactions take place.The distribution of physical fields such as flow,temperature and concentration field in the reaction shaft and the coupling characteristics between them have significant impacts on the smelting process.Deeply understanding the distribution and synergetic characteristics of multi-physical fields in the reaction shaft is very helpful for both optimization of the operational parameters and improvement of the production process.Taking the smelting process of a copper flash smelting furnace as the research object,numerical simulation was carried out to study the gaseous fields of velocity,temperature and concentration in the reaction shaft,and the synergistic relationship between the physical fields are also investigated in detail.The main research contents and conclusions are summarized as follows:（1）Taking the industrial flash smelting furnace as the prototype,the numerical models to simulate the gas-particle two-phase flow,heat and mass transfer and chemical reactions in the flash smelting process was established.Based on the field synergy principle,the synergy angleβbetween the gaseous velocity and temperature gradient,the synergy angleθof the gaseous velocity and its concentration gradient,and the synergy angleφof gaseous temperature gradient and the concentration gradient were defined respectively.（2）Numerical simulation was performed for typical flash smelting processes,and the field synergy analysis of the gaseous physical field was carried out.The results showed that the area with the fastest gas temperature increase in the reaction shaft was located in the range of height from 2 to 5 m,which was corresponding to the area with the fastest O2consumption and SO2 generation rate.This range was also the area with smaller synergy angleβandφ.The area with smaller synergy angleθwas mainly located at the edge of the central gas column and the intense combustion area of the concentrate in the furnace.（3）Numerical simulation and synergetic analysis were carried out for the synergetic relationship of multi-physical fields in the flash smelting furnace under different airflow organization modes.The results showed that the distribution of gas phase velocity,temperature and concentration field in the reaction shaft was optimized to a certain extent after adding swirling air on the basis of the CJD（Concentrate Jet Distributor）nozzle structure.The synergy angleβandφwith swirling air reached the minimum value earlier than those without swirling air in CJD nozzle.And the synergetic relationship between gas velocity and concentration gradient in the range of height from 3 to 4 m was also improved,indicating that increasing swirling air was conducive to accelerating the heating of concentrate and promoting the combustion of concentrate.（4）The single factor analysis was carried out to understand the influence of the main operating parameters of CJD nozzle（process air velocity,dispersed air volume,swirling air volume and central oxygen volume）on the multi-physical field synergy in the reaction shaft after adding swirling air.The results showed that the synergy angleβdecreases with the increase of dispersed air volume,swirling air volume and central oxygen volume,which was beneficial to the improvement of convective heat transfer in the furnace.Although the increase of process air velocity reduced the synergy angleβ,it reduced the peak position along the shaft height,which was not conducive to accelerating the ignition reaction of concentrate.Increasing the process air velocity and swirling air volume,reducing the dispersed air volume and central oxygen volume made the area of synergy angleφ<90°smaller and the corresponding height of the reactor decrease,which was not conducive to the reactions in furnace.The synergy angleθwas not significantly affected by the operating parameters. |
