Energy-saving Principles of Variable Frequency Single Tank Flotation

As the main equipment for flotation process in dressing plants, flotation equipment are equipped with many motors usually in order to ensure the normal operation of their all parts. The motors have the two following characteristics. First, most of them are underloaded, with too low power factor. Second, their rated speed is not the optimal rotary speed of flotation, namely, they will not influence the lowest energy-saving rotary speed of the flotation result. However, motor frequency converter in speed adjustment system can not only investigate the technical effect via different rotary speed but also can improve the power factor of motors. Therefore, variable frequency single cells flotation equipment has many advantages over the other single cells flotation equipment.

According to flotation principle, aerating agitation degree of minerals is affected by grinding fineness, reagent system, stage of flotation process and other factors. In general, the same specification is chosen as much as possible in the model selection of flotation equipment, with the aim of convenient management, maintenance and equipment purchase, as well as the coordination of various operations. The rotary speed of motor under given voltage is definite, but aeration or agitation requirement varies from different flotation operation. Consequently, problems like motor underloading and too low power will occur in some flotation equipment. Compared with the normal single cells flotation equipment, variable frequency single cells flotation equipment is additionally equipped with frequency conversion cabinet beside electric control cabinet. Inside frequency conversion cabinet, each agitation motor of flotation equipment is provided with one frequency converter and change-over switch of power frequency and variable frequency which enable the equipment to work with these two frequencies without breaking down as a result of variable frequency equipment failure. Meanwhile, there is also a PLC used for logic control in every frequency conversion cabinet. It is though adjusting the rotary speed of motors to reduce unnecessary energy consumption that variable frequency single cells flotation equipment achieve an energy-saving purpose.

Because of the rising ore dressing costs, variable frequency single cells with simple operation and energy-saving features will be further generalized for some time to come.