A two component model is used for calculation of the residence time. A coarse solids fraction and a fine solids fraction are considered. The coarse fraction is the material of interest in terms of the scrubbing residence time while the fine fraction is assumed to be part of the fluid (slurry) flow and to have a different residence time.

Avoided energy cost of producing minerals: The case of iron ore. ... The screen reports to the grinding circuit, which consists of two ball mills. ... For the flotation process, the direct results were the retention time and power consumption, as shown in Table 3.