EXPERIMENTAL-STUDY OF SPLASH GENERATION IN A FLASH SMELTING FURNACE

A survey of previous studies of splash formation in metallurgical vess els revealed that little information is available to characterize and describe the processes involved in splash formation. An experimental s tudy of splash formation by top submerged gas injection was carried ou t in the settler region of the nickel flash smelting furnace at the Ka lgoorlie Nickel Smelter (KNS) both to obtain some visualization of the splash mechanisms that occur on a plant scale and to measure the amou nt of splash being formed. Video images taken of the splashing showed that large sheets of melt were formed by the escaping gas and subseque ntly thinned into ligaments which then broke up into large splash drop s. The video could only resolve a minimum size of 2 cm. The large spla sh drops visible on video have an initial velocity between 1 and 2 m/s , are unstable, and fall back into the bath after traveling a short di stance. The analysis identified two major splash forming mechanisms. F irst, the gas injected resulted in the bulk movement of the melt to fo rm a cavity and large sheets of melts being thrown around the point of injection. The area affected by this splash mechanism can be predicte d successfully by using an energy balance between the removal of the m elt in the cavity and the energy of the gas being injected. Second, th e slag free surface within the cavity is highly unstable, and through the Kelvin-Helmholtz instability mechanism, small splash droplets are generated which are carried into the furnace's top space. A model prop osed for the formation of the smaller splash droplets predicted that t he splash collected decreases exponentially with increasing height abo ve the slag free surface from the point of splashing, and this is in a greement with the experimental results obtained.