The selection of the number of grinding stages for lead-zinc ore is mainly determined based on the associated relationship between lead-zinc and other gangue minerals, as well as the embedded particle size of the ore. The purpose of grinding is to dissociate lead and zinc from the gangue mineral monomers. Different lead-zinc ores have different compositions and different embedded particle sizes. Naturally, the particle sizes that can complete the monomer dissociation are also different. This particle size determines the grinding process. Number of ore sections. The commonly used grinding stages of lead-zinc ore ball mills include one-stage grinding, multi-stage grinding and tailings regrinding.

1. One-stage grinding of lead-zinc ore
If the symbiotic relationship between the gangue minerals and metal minerals involved in the lead-zinc sulfide ore is not complicated, and the coarse-grained minerals are unevenly dispersed, the lead-zinc ore ball mill can choose a one-stage grinding process.

Advantages of first-stage grinding of lead-zinc ore

Compared with the two-stage grinding process, the main advantages of the one-stage grinding process of the lead-zinc ore ball mill are: fewer classifiers and lower investment; easy production operation and simple adjustment; there are sections between sections Regarding the transportation of intermediate products, multiple series of grinding machines can be placed at the same level, so the configuration of the equipment is relatively simple; the shutdown of one section of the lead-zinc ore ball mill or classifier will not affect the work of another grinding section. The loss is small; each series can be installed with larger equipment. The disadvantages of the first-stage grinding process are: the feed particle size range of the lead-zinc ore ball mill is very wide, it is difficult to load the balls reasonably, and the grinding efficiency is low; the classification overflow fineness in the first-stage grinding process is generally -200 mesh accounting for less than 60% , it is difficult to obtain a finer final product. In addition, the particle size composition of lead-zinc ore grinding products is not very good, which is not conducive to separation.

2. Multi-stage grinding of lead-zinc ore
The multi-stage grinding process of lead-zinc ore ball mill is mainly suitable for processing the complex symbiotic relationship between useful minerals and gangue minerals, or when the useful minerals are unevenly distributed, a multi-stage process can be used. Generally, a two-stage process is sufficient. . Lead-zinc ore adopts a multi-stage grinding process, which can fully realize the monomer dissociation between useful minerals and gangue minerals, so that useful minerals can be effectively recovered. Two stages of grinding can grind lead and zinc raw ore to more than 80% -200 mesh.

Advantages of two-stage grinding of lead-zinc ore

The advantage of two-stage grinding of lead-zinc ore ball mill is that the ore can be coarsely ground and finely ground in different grinding sections. The two grinding sections can adopt different grinding conditions: during coarse grinding, larger steel balls are installed and a higher speed is used, which is beneficial to improving the grinding efficiency; during fine grinding, smaller steel balls are installed And using a lower rotation speed can also improve the grinding efficiency.

The two-stage grinding advantage of lead-zinc ore ball mill is that it is suitable for stage separation. When dealing with unevenly distributed ores and ores containing minerals with large specific gravity, the sorting operation is used in the grinding cycle; the minerals that have been separated into monomers can be sorted out in a timely manner to prevent over-crushing, which is beneficial to improve It is a quality indicator for lead-zinc ore beneficiation; at the same time, it can reduce the aggregation of lead-zinc ore minerals in the graded return sand and improve the classification efficiency of the classifier.

3. Lead-zinc ore concentrate/tailings regrinding
Generally speaking, the tailings regrinding process or coarse concentrate regrinding process of lead-zinc ore is mainly suitable for lead-zinc sulfide ore concentrator, and multi-stage grinding is commonly used. For example, the Shuikoushan lead-zinc deposit is a medium-temperature hydrothermal metasomatic deposit type. Most of them are dense and massive ores, only a few of which are fine vein disseminated ores, and some brecciated ores are unevenly embedded. Useful minerals are distributed, and this type of lead-zinc ore mostly adopts the coarse concentrate regrinding process.

In the actual operation of the lead-zinc ore ball mill, in order to effectively promote the full monomer dissociation of useful minerals without over-grinding, the raw zinc blend ore is ground to the standard of -200 mesh 50% to 60%, and then completed The tailings are swept and selected to reach -200 mesh 80%, while the lead coarse concentrate contains zinc minerals, sulfur minerals, and galena minerals in aggregate state. Afterwards, they are ground again to achieve a -More than 90% of 325 mesh, fully dissociating galena, sphalerite, pyrite, etc. into monomers.