Abstract:The residence time of pulp in the flotation cell is an important parameter of the flotation circuit, which is helpful to understand the flow characteristics and mixing degree in the flotation machine, thus guide the operation of the flotation cell, and optimize the design of the flotation machine. Taking the 30l laboratory flotation machine to do the research, the residence time distribution of the liquid phase of the 30l flotation cell was studied by using experimental fluid mechanics method. the experiment was carried out by using impulse response method, and the residence time distribution of the flotation machine was obtained, which was compared with the mean residence time. The probability of short circuit and dead zone in the tank and where it appeared in the flotation cell were studied by using the two-parameter model. The results show that the difference between the average residence time of the test and the mean residence time is very small, and the probabilities of short circuit and dead zone are respectively.