froth flotation of copper

How does copper sulfide flotation beneficiation work?

Generally, copper sulfide ore mainly includes single copper sulfide ore and polymetallic copper sulfide ore. The flotation process of the former is generally simple, and the flotation process of the latter is more complicated.


1. Single copper sulfide flotation

The mineral composition of a single copper sulfide ore is simple. The copper minerals mainly include chalcopyrite, chalcocite, bornite, copper blue and a small amount of copper oxide minerals. Gangue minerals vary with the type of deposit, mainly quartz, calcite, feldspar, dolomite, sericite, chlorite, etc. Since the floatability of copper minerals and gangue minerals are quite different, flotation methods are often used for separation.

It is worth noting that due to different occurrences of single copper sulfide ore, its structure and structure change greatly, which makes it difficult to separate the monomers of copper minerals and gangues, and the fineness of grinding has become an influence on single sulfide. The key to the flotation index of copper ore. Generally, there are three main flotation processes for single copper sulfide ore:

One stage grinding-flotation process

The process is suitable for processing copper minerals with coarse and uniform grain size, loose copper minerals and gangues, and smooth and flat contact edges.

Usually, when the raw ore is ground to -200 mesh, which accounts for 50-60%, the copper mineral can basically be dissociated into monomers. After rough selection, sweep selection, and one to three selections, a better flotation index can be obtained. This flotation process is simple, and the beneficiation cost is low, and it is mostly used in small and medium-sized copper concentrators.

One-stage grinding-flotation-re-grinding process flow of coarse concentrate

This process is mostly suitable for processing single sulfide ore or copper-molybdenum ore of porphyry copper ore.

According to the characteristics of copper mineral inlay, the raw ore is ground to -200 mesh by one-stage grinding to account for 40-70%, and a large amount of tailings are discarded by roughing and sweeping. After the coarse concentrate is re-grinded, the copper concentrate can be obtained by performing two to three selections. The one-time beneficiation tailings in the flotation cycle can be discarded after scavenging, or it can be returned to the roughing cycle after being concentrated. A small number of copper ore dressing plants will separately regrind the middle ore for treatment. This process can enable the copper ore dressing plant to obtain better economic benefits when the grade of the original ore is low and the processing volume is large. In addition, due to the regrind of the coarse concentrate, the particle size is finer, the monomer dissociation degree of copper minerals, gangue minerals and pyrite is better, and the quality of the flotation concentrate is also higher.

Two-stage grinding-two-stage (or one-stage) flotation process

For copper ore with uneven thickness, in order to dissociate most of the copper mineral monomer, it is necessary to grind the ore to -200 mesh, accounting for 80%, or even finer. At this time, the two-stage grinding is better than the one-stage grinding in terms of grinding efficiency and preventing copper minerals from over-smashing.

When using two-stage grinding-two-stage flotation, after the ore is coarsely ground in the first stage, a part of the coarse copper minerals can be flotated to avoid excessive crushing. This part of the concentrate is generally of high grade and can be used directly as a concentrate, or enter the final beneficiation, or be combined with the concentrate obtained by the flotation after the two stages of grinding. If there are few coarse-grained copper minerals in the ore, a two-stage grinding-one flotation process can be used. The flotation cycle adopts sweeping and two to three times of beneficiation, and the middle mine generally returns to the second stage of grinding cycle. Relatively speaking, this process has high grinding costs, complicated equipment configuration and production operations, and is mostly used in large and medium-sized copper concentrators.

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2. Flotation of polymetallic copper sulfide ore

Generally, polymetallic copper sulfide ore not only contains a variety of copper minerals, but also often coexists with various minerals such as pyrite, galena, sphalerite, etc. The structure and composition of the minerals are complex, and the symbiotic relationship between the minerals is dense. Based on the characteristics of the above ore, the flotation process of polymetallic copper sulfide minerals mainly includes the following categories:

Multi-stage flotation process

This process is mainly aimed at copper sulfide minerals containing iron sulfide, and its composition is relatively simple. Therefore, the multi-stage flotation process is a conventional flotation process of copper sulfide ore, and its focus is on the separation of copper and sulfur. Generally, a multi-stage roughing-multi-stage selection-sweeping closed-circuit flotation process is adopted, which can obtain a good recovery effect, but for copper sulfide ore with a more complex composition, the ideal separation effect cannot be achieved.

Step-by-step priority flotation process

Distribution priority flotation is suitable for complex copper sulfide ores. The types of copper ores are complex, mainly azurite and chalcopyrite. Although the focus is still on copper sulfur separation, due to the complex structure, the conventional flotation process can not obtain qualified copper concentrate.
Due to the different floating speeds of various copper mines, the copper minerals that are easy to float can be roughly selected first, and then the copper minerals that are difficult to float can be reground and the middling ore can be re selected, and the copper concentrate can be recovered together to ensure the grade and recovery rate.

Flotation-mixed concentrate separation process

This process is mainly applied to copper sulfide ore with low grade and complex symbiosis relationship with chalcopyrite, sphalerite and galena. A large amount of gangue minerals are discarded after rough grinding and rough selection of the raw ore to obtain a copper-lead-zinc mixed concentrate, and then the copper-lead-zinc concentrate is separated and processed to obtain a single copper mineral. This process can separately recover the three minerals of copper, lead and zinc, but it is easy to cause incomplete separation of the mixed concentrate.