1. Crushing and screening
Lead-zinc ore mainly contains metal minerals such as galena, sphalerite, pyrite and chalcopyrite, and the crushing operation mostly adopts two stages and one closed circuit crushing and screening process.
The raw ore is sent to the jaw crusher through the trough feeder for coarse crushing. The coarsely crushed material is fed into the vibrating screen through the belt conveyor for screening. The qualified ore particles enter the grinding stage, and the unqualified ore particles enter the grinding stage. Then it is sent to the cone crusher by another belt conveyor for secondary crushing operation, forming a closed circuit, until all the minerals are qualified, and transported to the powder ore bin, ready to enter the next stage.
2. Grinding classification
The crushed and qualified minerals are fed from the powder ore silo through the belt feeder and belt conveyor for grinding operation. The ground pulp is discharged to the linear vibrating screen for screening, and the qualified pulp is fed into the hydrocyclone by the slurry pump. The unqualified pulp flowing out of the linear vibrating screen and the hydrocyclone will be returned to the ball mill for regrinding until all the pulp is qualified. The overflow part after being checked and classified by the hydrocyclone enters the next stage.
3. Mineral dressing stage
The composition of lead-zinc ore is complex and diverse, and the floatability varies greatly, so flotation technology is mostly used. Lead-zinc ore is divided into three types according to the degree of oxidation: sulfide lead-zinc ore, oxide lead-zinc ore, and mixed lead-zinc ore. In the actual beneficiation process, the appropriate flotation method should be selected according to the oxidation degree of lead-zinc ore. The following is an example of common lead-zinc sulfide flotation separation:
Priority flotation method: The qualified pulp classified by the hydrocyclone enters the stirring tank, and then a strong collector is put into the stirring tank to carry out the lead flotation process, and the lead concentrate is preferentially recovered; then the tailings are passed through the slurry pump. It is sent to the high-efficiency stirring tank, and the zinc is activated by the chemical agent, and then enters the flotation machine for flotation operation, and finally the zinc concentrate is recovered.
Mixed flotation method: The qualified pulp classified by the hydrocyclone enters the stirring tank, and the collector is used to flotate the lead sulfide ore and part of the zinc sulfide ore at the same time to obtain the lead-zinc mixed concentrate, which is then pumped to the slurry. Enter the hydrocyclone for classification, and the qualified pulp enters the high-efficiency stirring tank; the unqualified part is returned to the ball mill for regrinding. Put chemicals into the stirring tank to remove the lead-zinc mixed concentrate, and then send it into the flotation separation operation.
In the flotation process, in order to effectively improve the concentrate recovery rate and concentrate index, appropriate flotation reagents will be added.
4. Concentration and dehydration
The pulp foam after flotation is fed into the thickener through the slurry pump, and the solid particles suspended in the pulp in the thickening tank settle under the action of gravity to separate the solid and liquid. discharge. The discharged ore sludge is pumped to the filter press through the slurry slurry, and the solid and liquid are separated through the filter medium, and finally the concentrate is obtained.
The material composition of lead-zinc ore is particularly complex. Different material compositions have different ore characteristics and need to be adopted differently. Whether the beneficiation process of lead-zinc ore is correct will directly affect the beneficiation effect. It is recommended to formulate a scientific and reasonable mineral processing process according to the specific mineral processing test report to avoid unnecessary economic losses.
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