Study On Level Control Of Flotation Cells

The proportion of mineral resources with the feature of low-grade, finely-dissemination particle and complex mineral composition is increasing in the world. The separation and purification of fine refractory ore has become more important in mineral processing industry than before, and it is much more prominent in our country. Flotation is an important means in the process of sorting fine-grained minerals. Study on level control of flotation cells has theoretical and practical significance, because the liquid level can directly affect concentrate grade and reclaimed efficiency.The study object in this paper is SKCF series of flotation machine, a production of General Equipment Company which is a company of the Northern Heavy Industries Group Co. Ltd. Steady liquid level means that the output flow equal to input flow, and the flow essentially is the kinetic energy, so I analyzed the energy flow within the flotation machine, based on the flotation theory and flotation craft requirements. And then I analyzed the energy flow, based on the superposition principle of energy and the analytic result above. So I could solve one by one, based on Euler assumption for centrifugal impeller, plan potential theory flow and other knowledge of Fluid Mechanics, to derive estimate model of volume flow about valve opening and liquid level.I selected inferential control structure with measurable output and designed the controller, because output of flotation cells can be measured but the main disturbance can’t be measured. The system designed in this paper can achieve unbiased steady-state, even if the model is not accurate, and its parameter is less than most existing system. So the system has a good usability.Finally I used the ControlLogix system produced by Rockwell Automation Inc.to design the software and emulate the system. The simulation results show that when the feed speed changes the system has smaller fluctuations and a smaller deviation in steady state, whether the estimated model is accurate or not, and the coupling strength between the flotation cells is effectively reduced.