Abstract: To solve the problems such as more awkward reaction way and large performance delay in the flash smelting process， a cold model experiment device of a CJD(central jet distributed) burner for flash smelting furnace was set up， and the change of particles dispersion near the burner with the process air and the distribution air was studied. The results showed that the particles dispersion leaving from the burner can be regulated. The particles disperse along the horizontal direction under distribution air， and concentrates in the central area under tower by process air. The momentum ratio can affect particles distribution directly， and the smaller it is， the particles are more concentrated in the central area under tower. Within the scope of experimental data， the mass segregation function， which means particles distribution uniformity index， can be fitted as the nonlinear exponential function with momentum ratio. In the case of moderate particles dispersion， the increasing multiples of distribution air are the same as that of loading rate and that of process air.

Key words: CJD burner, particles distribution, momentum ratio, segregation function, copper flash smelter