Lead-zinc ore is a mineral rich in metal elements lead and zinc. Lead and zinc are extremely close in nature, especially in primary deposits, and often coexist. However, there are 11 kinds of lead minerals and 6 kinds of zinc minerals that can be used in industry, mainly galena and sphalerite. There are smithsonite, white lead ore and so on. Lead and zinc are widely used in electrical industry, machinery industry, military industry, metallurgical industry, chemical industry, light industry and pharmaceutical industry. In addition, lead metal also has many uses in nuclear industry, petroleum industry and other sectors.
Lead-zinc ore processing and production process
The processing and production process of lead-zinc ore mainly includes three processes: crushing, grinding and beneficiation.
In the crushing process, the three-stage closed-circuit crushing is a more modern method suitable for the crushing of high-hardness lead-zinc ore, which can complete the work of ore crushing and partial dissociation, thereby improving the subsequent grinding efficiency.
In the grinding process, the two-stage one-closed grinding is an efficient grinding process, which can make the lead-zinc ore grind more fully.
In the beneficiation process, the integrated rapid flotation technology can be used to improve the original complex flotation system into two sets of integrated rapid flotation systems, which greatly shortens the process, and is conducive to ensuring concentrate quality and reducing system investment.
Stage 1: Crushing and screening
The large pieces of lead-zinc ore are evenly sent to the jaw crusher or mobile jaw crushing station (primary crushing) by the vibrating feeder through the silo for coarse crushing.
The coarsely crushed lead-zinc ore is screened by a vibrating screen, and then sent to a single-cylinder hydraulic cone crusher (middle crushing) by a belt conveyor for secondary crushing.
The crushed lead-zinc ore material is sent to the multi-cylinder hydraulic cone crusher for fine crushing.
Stage 2: Grinding
The 0-12 mm lead-zinc powder sieved by the vibrating screen is evenly sent to the ball mill for grinding, and sieved by the screw classifier, and those that do not meet the requirements are sent to the ball mill to continue grinding.
Stage 3: Magnetic Separation
The lead-zinc powder that meets the mineral processing requirements is sent to the magnetic separator for strong magnetic separation and magnetic separation to remove sundries.
Stage 4: Drying
The obtained lead-zinc powder is sent to a dryer for drying to obtain lead-zinc fine powder.
Lead-zinc ore use
Lead and zinc are widely used in electrical industry, machinery industry, military industry, metallurgical industry, chemical industry, light industry and pharmaceutical industry. In addition, lead metal also has many uses in nuclear industry, petroleum industry and other sectors. More than 80% of the world’s lead is used to produce lead-acid batteries.
Zinc is an important non-ferrous metal raw material, and zinc is second only to copper and aluminum in the consumption of non-ferrous metals. Zinc metal has good ductility, wear resistance and corrosion resistance, and can be made into alloys with better physical and chemical properties with various metals.
The main products produced by primary zinc enterprises are: metal zinc, zinc-based alloys, and zinc oxide. These products are widely used, mainly in the following aspects:
Galvanized. Used as anti-corrosion coating (such as galvanized sheet), it is widely used in automobile, construction, shipbuilding, light industry and other industries, accounting for about 46% of zinc consumption.
Manufacture of copper alloys (such as brass). Used in automobile manufacturing and machinery industry, accounting for about 15% of zinc consumption.
For casting zinc alloy. Mainly for die castings, used in automobile, light industry and other industries, accounting for about 15% of the amount of zinc.
Used in the manufacture of zinc oxide. It is widely used in rubber, paint, enamel, medicine, printing, fiber and other industries, accounting for about 11% of the amount of zinc.
It is used in the manufacture of dry batteries, in the form of zinc cakes and zinc plates, accounting for about 13% of the zinc consumption.
Lead-zinc mine tailings treatment method
Common lead-zinc mine tailings treatment methods mainly include tailings recycling, tailings dry discharge, goaf backfilling and production of building materials.
1. Re-selection and recovery of lead-zinc ore Lead-zinc sulfide tailings often contain galena, sphalerite, pyrite, chalcopyrite, and gangue minerals include calcite, quartz, dolomite, mica, etc. The regrinding-flotation process is mostly used to process lead and zinc mine recycling.
The composition of lead-zinc oxide tailings is more complex and the associated components are unstable. Therefore, priority flotation process is chosen as the main separation process, and desliming operation is performed before flotation to improve the flotation index and the dosage of chemicals.
Mixed lead-zinc ore tailings contain both lead-zinc oxide ore and lead-zinc sulfide ore, which are usually separated by mixed-partial flotation process or mixed-preferred flotation process. Separated from zinc concentrate.
● Re-selection and recovery of sulfur and iron If the lead-zinc tailings contain refractory pyrrhotite, the sulfur content of iron concentrate exceeds the standard due to its influence. Therefore, it is necessary to strengthen the recovery of sulfur to reduce the content of harmful impurities in the iron concentrate. Flotation-weak magnetic separation- The combined flotation process recovers sulfur and iron from lead and zinc tailings.
● Re-selection and recycling of barite The combined gravity-flotation process recovers barite from lead-zinc tailings. The lead-zinc ore tailings are sorted by the spiral chute-desulfurization flotation-regrinding-barite flotation process, which can effectively recover the low-grade barite in the lead-zinc tailings.
● Re-selection and recovery of feldspar and quartz The components affecting the quality of feldspar and quartz in lead-zinc tailings are mainly minerals such as siderite, mica and a small amount of fluorite. The combined magnetic-floating process can be used to recover feldspar and quartz in the tailings.
2. Dry discharge of lead-zinc mine tailings The dry tailings discharge process relieves the pressure on the storage capacity of the tailings pond, reduces the potential safety hazards of the tailings pond, and the use of backwater reduces the pressure on sewage treatment and saves the cost of mine production and operation.
3. Backfilling of lead-zinc mine tailings goaf Using tailings to fill mine goaf is one of the effective ways to directly use lead-zinc mine tailings, especially for mining enterprises that have nowhere to set up lead-zinc mine tailings ponds, the full tailings cementation filling technology can be used. Or high water consolidation full tailings backfill technology to backfill the goaf has greater environmental and economic significance.
4. Production of building materials from lead-zinc mine tailings
The composition of lead-zinc tailings is similar to that of cement raw meal, which can partially replace clay, iron powder and aluminum raw materials and mixed into cement ingredients, and the trace elements contained in tailings have good mineralization and fluxing effect on raw meal calcination. It can improve the scorchability of raw meal. Lead-zinc tailings are finer in particle size and can be used as admixtures to reduce power consumption and save energy in cement grinding.