How to Realize the Lead-Zinc Tailings Reprocessing and Dry Stacking Together?
Shandong Xinhai Mining Technology & Equipment Inc.
Xinhai provides ore processing plant and full set equipment: Ball mill, Hydrocyclone, Flotation, Washing plant, CIP, CIL
With the continuous exploitation and utilization of lead-zinc resources, the emission of lead-zinc tailings goes in increasing year by year, which inevitably brings a series of environmental issues, and further stimulates the development of lead-zinc tailings treatment and comprehensive utilization.
Aiming at this situation, here are methods about reprocessing and dry stacking of lead-zinc tailings, mainly including:
lead & zinc, sulfur & iron tailings, barite, feldspar & quartz recycling from lead-zinc tailings, as well as tailings dry stacking, lead-zinc tailings backfilling into gob and its production of building materials.
Boiled down to the low level of early beneficiation technology and equipment, many lead-zinc tailings still contain many valuable components, such as lead, zinc, sulfur, iron, barite, feldspar, quartz, mica and so on. In this regard, we can carry out secondary recovery and utilization of valuable components in lead-zinc tailings according to their types, contents and occurrence states at this stage.
Lead-zinc sulfide tailings often contain galena, sphalerite, pyrite, chalcopyrite, gangue minerals including calcite, quartz, dolomite, mica, etc., using regrinding-flotation process for lead-zinc reprocessing stage.
The mineral components of lead-zinc oxide tailings are more complex and the associated components are unstable. Therefore, priority flotation process is selected as the main separation process, and desliming operation is carried out before flotation separation, so as to upgrade flotation indexes and reduce reagent dosage.
The mixed lead-zinc tailings contain both oxide and sulfide lead-zinc ore. Usually, the mixed-partial flotation process or the mixed-preferential flotation process can be considered to separate the oxide lead-zinc ore, lead concentrate and zinc concentrate in turn.
If the refractory pyrrhotite exists in lead-zinc tailings, the sulfur content of iron concentrate will exceed the standard due to its influence. Therefore, it is necessary to strengthen the reprocessing of sulfur to reduce the content of harmful impurity sulfur in iron concentrate. The combined process of flotation-weak magnetic separation-flotation method is used to wash sulfur and iron in lead-zinc tailings.
The recovery of barite from lead-zinc tailings can be realized by gravity separation-flotation combined process. Especially regarding to low grade barite in lead-zinc tailings, the process of ‘spiral chute -desulfurization flotation-regrinding-barite flotation ’ can be more effectively.
The main components affecting the quality of feldspar and quartz in lead-zinc tailings are siderite, mica and a small amount of fluorite and other minerals. The combined solution of ‘magnetic -flotation separation process’ can be applied to dress feldspar and quartz in lead-zinc tailings.
Lead-Zinc tailings dry stacking technology alleviates the storage pressure of tailings pond, reduces the safety hidden danger of tailings pond, reduces the pressure of sewage treatment, saves the cost of mine production and operation, which meets the requirement of national green environmental protection mine construction.
The lead-zinc mine tailings treatment method greatly saves the construction cost and routine maintenance cost of the traditional tailings pond, realizes the full utilization of the backwater, avoids the risk of dam break, overtopping and dam break of the tailings pond, and is easier to stop and use. It is in line with the current national policies for tailings discharge, and has obvious social and economic benefits. It also lays the foundation for the development of tailless mines and green mines.
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Taking the common dewatering process of dry stacking of lead-zinc mine tailings —‘hydrocyclone + dewatering screen + filter press ’ as an example, the tailings are transported to the rubber pump tank by self-flow or slurry pump and are pumped into the concentrated hydrocyclone group. The bottom flow of the hydrocyclone is self-flowed to the dewatering screen. The material on dewatering screen is transported out of the workshop by belt, and the material under screen is transported to the thickener by pump . The cyclone overflow flows to the thickener. After concentration, the filter cake is pressed by the filter press through using the filter press feeding pump. Then the filter cake is transported out of the workshop with a belt for storage. The filtrate of the filter press and of the dewatering screen flows to the filtrate buffer tank, and then transported to the thickener by the pump. The thickener overflow flows to the backwater tank, sending back to the concentrator by the pump after clarified.
The lead-zinc tailings dry stacking treatment greatly saves the construction cost and routine maintenance cost of the traditional tailings pond, realizes the full utilization of the backwater, avoids the risk of dam break and overtopping, which is easier to stop and use. It is in line with the current national policies for tailings discharge, and has obvious social and economic benefits. It also lays the foundation for the development of tailless mines and green mines.
Filling mined-out area with tailings is one of the effective ways to directly use lead-zinc tailings. Especially for mining enterprises without lead-zinc tailings reservoirs, it has greater environmental and economic significance to backfill mined-out area with tailings.
As a good filling material, tailings can be used for local materials and wastes, and the cost of collecting, crushing, transportation and other production of filling gravel is exempted. For lead-zinc ore bodies with high value, tailings can improve pillar recovery conditions and reduce dilution loss. Appropriate amount of cement or other cementing materials are often added to the filling material, so that loose lead-zinc tailings are condensed into a whole with certain strength.
The recovery of valuable elements from tailings can only realize the comprehensive recovery of a small amount of valuable elements in tailings, but it cannot greatly reduce the amount of tailings. Lead-zinc tailings can be used as production building materials.
The composition of lead-zinc tailings is similar to cement raw material, which can partially replace clay, iron powder and aluminum raw materials into cement ingredients. The trace elements contained in the tailings have good mineralization and melting effect on raw material calcination, and can make raw material burnability better. Lead-zinc tailings with fine particle size can be used as admixture to reduce cement grinding power consumption and save energy.
Realizing the lead-zinc tailings reprocessing and dry stacking together, not only reuse of resources also balance the harmonious development between efficiency and environment. In the practical application, it is suggested that the suitable lead-zinc tailings treatment and comprehensive utilization should be determined by comprehensively considering the properties, scale and investment return of lead-zinc tailings, in order to customize the reasonable lead-zinc tailings treatment solutions.
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