Flotation technology is mostly used for copper ore dressing. The case introduced in this article is a single copper grinding and floating operation project, that is, the production process of processing copper ore separately, with two parallel grinding and floating operation automation systems.The system implements automation technology transformation for all grinding grading operations, dosing links of flotation operations, sampler metering, etc., to realize the comprehensive automation of single copper grinding and flotation operations.Let's take a look at the operation process, parameter control method and advantages of the grinding and floating system.

1. Copper ore grinding and flotation operation process

The grinding and floating system includes two stages of grinding ore.The first section consists of a rod mill and a spiral classifier to form a closed-circuit mill, and the second section consists of a ball mill and a cyclone to form a closed-circuit mill.The sorting operation consists of a flotation machine and a shaker.

2. Parameter control method of copper mine grinding and floating system

(1) Feed flow

Detection: The virtual electronic belt scale is used for detection, which is composed of a scale frame, a force sensor, etc., which has the advantages of high accuracy and good reliability.

Control: Adjusted by the vibration regulator, there are automatic and manual control methods, which can automatically switch to the miner, and provide a variety of cumulative calculation and display functions, as well as upper and lower limit alarm functions.

(2) Mill load

Detection: The load is indirectly detected by detecting the current of the grinder motor.

Control: According to the automatic analysis and judgment of the current volume characteristics, adjust the ore feed volume, display the status of the mill and alarm. In actual control, the ore feed volume is controlled in the left part of the “optimal zone”, and the dynamic characteristics are tracked by fuzzy control.

(3) The amount of sand returned by the classifier: the amount of sand returned is determined by detecting the flow rate of the classifier, and then the operation of the grinding and grading operation is analyzed.

(4) Grinding concentration: the water supply is calculated through a mathematical model to control the grinding concentration, and the control circuit provides a panel for setting relevant parameters.

(5) The overflow concentration of a classifier: it is indirectly detected by the relevant calculation method, which has a corresponding relationship with the fineness, which is detected by the density meter and controlled by the intelligent cascade control loop.

(6) The inflow pressure, concentration, and level of the pump tank of the cyclone

Inflow concentration: The supplementary water volume of the pump tank is controlled by adjusting the pump tank, the nuclear density meter is used to detect, the electric valve controls the water volume, and the concentration is set according to the process requirements.

Inflow pressure: By adjusting the speed control of the conveying pump, the overflow particle size and sand concentration can be improved by appropriately increasing it, but it needs to be controlled within a suitable range.

The liquid level of the pump tank is detected by an ultrasonic level meter, and the liquid level is controlled by controlling the pump flow rate (speed), and a coordinated controller is used to control the inflow pressure and the liquid level of the pump tank at the same time.

(7) Sampling machine slurry metering: The technical transformation of the slurry sampling machine, the measurement signal is transmitted to the PLC for processing, the relevant ore volume data is calculated and displayed.

(8) Automatic control of flotation dosing: PLC is used as the main mechanism to form a dosing control subsystem, managed by the upper computer, which can achieve accurate dosing.

(9) Fuzzy control of grinding and grading operations: different control strategies are used, and fuzzy control is used for complex loops. The given value of the intelligent PID control loop is calculated by the fuzzy controller, and the control parameters are adjusted in time according to changes.

3. Advantages of copper mine grinding and floating automation system

The system has reliable performance, easy operation, low maintenance, and a high degree of automation. There is basically no need for workers to operate the production site.

It realizes the detection and control of the load of the mill and the fuzzy control of the grinding grading operation, and can automatically coordinate the control loops.

It provides functions such as historical data record retrieval, voice alarm, online debugging, and remote monitoring.

After being put into operation, the processing capacity increased by 5.2%, the ore supply equilibrium rate increased from 61% to 96%, and the economic benefits and technical indicators were significant.

Through this case of copper ore grinding and flotation automation system, we know that today's mineral processing plants have abandoned the traditional manual operation mode of mineral processing plants and adopted automated control systems instead. This not only improves the technical level of mineral processing technology in our country, saves labor costs, but also provides a safe and easy-to-operate plant selection environment.In the future, intelligent plant selection will fully replace traditional plant selection, and mining will also enter a new era of automation, intelligence, and mechanization.