Lead-zinc tailings refer to the waste residue discharged after valuable elements are extracted from lead-zinc ore through beneficiation. Common lead-zinc tailings include sulfide lead-zinc tailings, oxidized lead-zinc tailings and mixed lead-zinc tailings. So how to recycle lead-zinc tailings?
Sulfide lead-zinc ore tailings often contain galena, sphalerite, pyrite, chalcopyrite, and gangue minerals include calcite, quartz, dolomite, mica, etc. For this type of tailings, the regrinding-flotation process is often used to recover the lead-zinc ore.
The advantage of this process is that it can accurately and efficiently extract lead and zinc minerals from the tailings and improve the recovery rate of resources. The specific process is: first regrind the tailings to achieve a particle size suitable for flotation, and then carry out flotation operations according to the appropriate reagent type, dosage and flotation conditions (such as slurry concentration, aeration volume, stirring intensity, etc.), and finally achieve the recovery of lead-zinc ore.
The tailings minerals of lead-zinc oxide ores have complex components and unstable associated components, making their mineral processing more difficult than those of lead-zinc sulfide ores. Therefore, the priority flotation process is usually chosen as the main separation process, and desliming operations must be performed before flotation.
This is because sludge will affect the flotation index, increase the consumption of chemicals, and is not conducive to the effective separation of minerals. Desliming before flotation can significantly improve the flotation index, reduce the dosage of chemicals, and make the subsequent flotation process easier. It can proceed more smoothly, improve the efficiency of flotation and the quality of concentrate, and thus better realize the recovery of valuable minerals in lead-zinc ore tailings.
Mixed lead-zinc tailings contain both oxidized lead-zinc ore and sulfide lead-zinc ore. In this case, mixed-partial flotation process or mixed-preferential flotation process is generally used for separation.
For example, when using the mixed-preferential flotation process, the mixed lead-zinc tailings are first mixed and floated to obtain mixed concentrates, and then the oxidized lead-zinc ore, lead concentrate and zinc concentrate are separated in turn according to the characteristics of the minerals. Through such a reasonable process flow, different concentrates can be effectively extracted from the complex mixed lead-zinc tailings to improve the comprehensive utilization value of the tailings.
Recovery of sulfur and iron: If the lead-zinc tailings contain refractory pyrrhotite, the sulfur content of the 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 impurity sulfur in the iron concentrate. At this time, the flotation-weak magnetic separation-flotation combined process is often used to recover sulfur and iron in the lead-zinc tailings. First, sulfur and other minerals are floated out by flotation, and then iron minerals are enriched by weak magnetic separation. After that, sulfur and iron are further purified by flotation. After this series of combined process operations, sulfur and iron are effectively recovered.
Recovering barite: The combined process of gravity separation and flotation is used to recover barite in lead-zinc tailings. For example, lead-zinc tailings are separated by spiral chute-desulfurization flotation-regrinding-barite flotation process. A part of barite is initially separated by gravity separation in the spiral chute, and then impurities such as sulfur are removed by desulfurization flotation. Then, regrinding is performed to further dissociate barite. Finally, low-grade barite in lead-zinc tailings is effectively recovered by barite flotation.
Recovering feldspar and quartz: The components that affect the quality of feldspar and quartz in lead-zinc tailings are mainly siderite, mica and a small amount of fluorite. The combined process of magnetic-flotation can be used to recover feldspar and quartz in tailings. First, magnetic minerals are removed by magnetic separation, and then through flotation, according to the differences in the surface properties of feldspar, quartz and other gangue minerals, corresponding flotation agents are added to separate feldspar, quartz and other minerals, and then their recovery is completed.
