Numerical study of MgO powder synthesis by thermal plasma

Abstract

Numerical calculations are presented in which homogeneous nucleation and growth of MgO particles in a thermal plasma reactor is simulated. The physical environment involves continuous cooling from very high temperatures. The numerical model involves a solution of the aerosol general dynamic equation coupled to a gas phase chemical kinetics calculation for generation of MgO monomers. The results indicate that the number of particles nucleated is a function of initial Mg concentration and of cooling rate in the nucleation region. The results are little affected if the assumed chemical rate constants are within one order of magnitude of upper-bound estimates. If, however, the rate constants are a factor of 100 lower than the estimates a large change is observed in the final results. In that case surface reactions are likely to play a prominent role in particle growth.