As zinc and lead mine resources are continuously exploited and utilized, the discharge of tailings from lead-zinc mines is increasing every year. Heavy metals in lead-zinc tailings enter the environment through leaching, weathering, and oxidation, causing serious damage to the environment. Thus, the focus is now on treating and using lead-zinc mine tailings disposal.
Lead-zinc mine tailings usually exist in the following forms:
- Sand tailings, this type of tailings are usually coarse in size, most of which are granular.
- Mud tailings: This type of tailings has a higher mud content, usually in lead-zinc oxide mines, where there are more granular ores.
- Fine ore tailings: This type of tailings is a common type of tailings in mines in my country.
How are lead-zinc tailings treated?
Re-selection and recovery of tailings, dry tailings discharge, waste backfill, and production of building materials.
Re concentration and recovery of lead-zinc mine tailings
Due to the low level of early beneficiation technology and beneficiation equipment, many lead-zinc tailings still contain many valuable components, such as lead, zinc, sulfur, iron, barite, feldspar, quartz, mica, etc. Accordingly, at this point, we are able to recycle the valuable components in the lead-zinc mine tailings disposal based on their types, their contents, and their respective states of occurrence.
1. Reconcentration of lead-zinc ore for recovery
Lead Zinc Sulfide Tailings often contain galena, sphalerite, pyrite, and chalcopyrite. Minerals found in gangue include calcite, quartz, dolomite, and mica. The regrinding-flotation process is often used for lead-zinc ore recovery.
The tailings of lead-zinc oxide ore minerals are more complex, and the associated components are unstable. Therefore, the preferential flotation process is often selected as the main separation process, and desliming operations are performed before flotation to improve flotation indicators and reagent dosage.
Mixed lead-zinc ore tailings contain both lead-zinc oxide ore and lead-zinc sulfide ore. The mixed-partial flotation process is usually used for separation, followed by lead-zinc oxide ore and lead concentrate separated from zinc concentrate.
2. Re-election and iron and sulfur recovery
The iron concentrate contains excessive sulfur if the lead-zinc tailings contain pyrrhotite, which is difficult to separate. Therefore, it is necessary to strengthen the recovery of sulfur to reduce the sulfur content of harmful impurities in the iron concentrate, and use flotation-weak magnetic separation- The combined flotation process recovers sulfur and iron from lead-zinc tailings.
3. Recycled barite
The combined process of gravity separation and flotation recovers barite from lead-zinc tailings. The lead-zinc tailings are subjected to spiral chute-desulfurization flotation-regrinding-barite flotation process selection, which can effectively recover low-grade barite in the lead-zinc tailings.
4. Then choose to recycle feldspar and quartz
The main components of lead-zinc tailings that affect the quality of feldspar and quartz are siderite, mica, and a small amount of fluorite. The combined magnetic-float process can be used to recover feldspar and quartz in the tailings.
Dry discharge of lead-zinc mine tailings
The dry tailings drainage process eases the storage pressure of the tailings pond, reduces the hidden safety hazards of the tailings pond, and the utilization of backwater reduces the pressure of sewage treatment and saves the production and operation costs of the mine. It is the national green environmental protection mine construction requirement.
Take the common lead-zinc mine tailings disposal dry discharge process program-hydrocyclone + dewatering screen + filter press dehydration process as an example, the tailings are transported to the rubber pump box by self-flow or pump, and the concentrated type is driven by the pump. In the hydrocyclone, the underflow of the cyclone flows by itself to the dewatering screen, the dewatering screen is transported out of the workshop with a belt for storage, and the filtrate is pumped to the thickener. The overflow of the cyclone flows to the thickener by itself. After being concentrated, the filter press is used to drive the feed pump into the filter press to form a filter cake, which is transported out of the workshop for storage with a belt, and the filter press filtrate and the thickener overflow flow to Return to the pool and pump it back to the processing plant for use after clarification.
Backfilling of lead-zinc mine tailings goaf
Using tailings to fill the mined areas of mines is one of the effective ways to directly use lead-zinc mine tailings, especially for mining companies that have nowhere to set up lead-zinc mine tailings ponds, the full tailings cemented filling technology can be used Or high-water consolidation and full tailings filling technology to backfill the goaf has greater environmental and economic significance.
As a better filler, tailings can be used for local materials and waste utilization, eliminating the cost of collecting, crushing, and transporting the production of filler and crushed stone. For high-value lead-zinc ore bodies, tailings can improve the extraction conditions of the pillars and reduce the dilution loss. Often an appropriate amount of cement or other cementing materials are added to the filler to condense the loose tailings into a certain strength overall.
Lead-zinc mine tailings production building materials
The recovery of valuable elements from tailings can only achieve comprehensive recovery of a small number of valuable elements in the tailings, but it cannot significantly reduce the number of tailings. Consider using lead-zinc mine tailings as production building materials.
The composition of lead-zinc tailings is similar to cement raw meal, which can partially replace clay, iron powder, and aluminum raw materials into cement ingredients, and the trace elements contained in the tailings have good mineralization and fluxing for raw meal calcination Function, can make the raw material burn better. The lead-zinc tailings have finer particle size and can be used as a mixed material to reduce the power consumption of cement grinding and save energy.
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