5 things you need to know about copper fines processing

Multotec’s insightful webinar on “5 things you need to know about Copper Fines Processing”, presented by Menzi Xulu, explores the benefits of using spiral concentrators in the extraction of copper. Xulu breaks down how spirals lead to upfront bulk mass rejection lowers CAPEX and OPEX, guarantees performance through full-scale testing, and delivers guaranteed ROI.

What is copper processing and why is it important?

It is the process of extracting copper minerals from the ore with the aim of upgrading low-grade ores into pure copper metal that can be sold. This is done through crushing and grinding the copper-containing rocks, then separating the copper minerals from the waste. This is done through methods such as flotation, or gravity separation using tools such as spirals – the method Xulu dives into in this webinar.

Processing copper is vital to the modern world, as copper is one of the most important industrial metals, used in almost everything, from electronics, construction and infrastructure, to transportation, industrial machinery and equipment.

What's the difference between copper ore and copper concentrate?

Copper ore is the raw material mined out of the earth – the raw rocks that contain copper minerals along with gangue (the waste material that remains after the minerals have been extracted).

Copper concentrate, on the other hand, is the copper product that emerges from the intensive and extensive processing operation. The bulk waste has been removed, leaving a finer, copper-enriched fraction. The degree of upgrade will depend on the mineral liberation size, which ultimately governs the beneficiation efficiency of the process.

In the webinar you’ll get a practical example of how Multotec’s DRC plant upgraded the copper output from 2.4% copper in the feed, to a concentrate of 20% copper after processing. From 100 tonnes of ore, 88 tonnes of waste was rejected just by using spiral concentrators.

What is the process of copper tailings?

Copper tailings are waste materials left after processing copper ore, which can be reprocessed to extract residual minerals. The process involves six steps:

1. Generation: Copper minerals are separated from waste at the processing plant, creating concentrate and tailings slurry.
2. Thickening: Slurry flows into thickener tanks where particles settle and clear water overflows.
3. Transportation: Thickened tailings are pumped to storage areas, often kilometres away.
4. Disposal/Storage: Methods include tailings dams, dry stacking, paste tailings, or underground backfill.
5. Water Management: Water is recovered, recycled, and monitored; seepage is collected and treated.
6. Rehabilitation/Closure: Tailings facilities are made permanently safe when operations cease.

What are the disadvantages of copper extraction?

When we think of extracting copper from the earth, the first disadvantage that would come to mind would generally be the impact on the environment – destruction of land, pollution, emissions, and biodiversity loss.

But there are also social, economic, and technical disadvantages like health impacts, declining ore grades, and water/energy intensity respectively. On a higher level, we can even see regulatory disadvantages like permitting delays, safety issues like working environment hazards, and legacy considerations like perpetual care needs.

What are the challenges in copper extraction?

While there is some overlap between the disadvantages and challenges in copper extraction, some of the more specific challenges include copper deposits being largely depleted; and mineralogical challenges like the microscopic nature of copper minerals being intimately mixed with gangue. Another challenge is that mining operations are having to dig deeper underground to reach copper deposits, presenting them with geotechnical risks, and logistics and infrastructure challenges.

What are the main methods of copper processing?

The method used for copper processing will depend on the type of ore and the size of the particles. When working with spiral concentration in processing, gravity concentration will be the primary method. This is where slurry flows down a helical trough, with heavier copper minerals migrating to the inner edge with the lighter gangue flowing to the outer edge. Multotec’s SC20, SC21, and HX5 spirals are ideal for the separation and cleaning of fine particles. The selection of the most appropriate spiral model is determined by the particle size distribution of the feed, the incoming feed grade, and the level of upgrade required to achieve the targeted product specification.

Other gravity methods include using jigs, shaking tables, centrifugal concentrators, or dense media separation (DMS).

What are the different types of copper ores and how do they affect processing?

There are two main categories of copper ores: copper sulphide ores and copper oxide ores. Sulphide ores are most common and use either flotation with chemicals that make copper stick to bubbles, or spiral concentration where spirals remove about 80% waste, with the remaining 20% taken into flotation. A smaller flotation plant is needed, saving money.

Copper oxide ores use either acid leaching to dissolve copper from crushed ore, or spirals to create concentrate that can be sold immediately – great for smaller operations to generate immediate revenue.

Closing thought

In an industry facing declining ore grades, rising costs, and environmental pressures, spiral concentrators prove that simple solutions deliver powerful results. No chemicals. No complex machinery. Just gravity separating heavy minerals from light waste.

This is shown in Multotec's African plants, where Zambian malachite upgraded from 3% to 20% copper, DRC ore transformed from 2.4% to 20% copper, and tailings turned from liability to revenue stream.

Sometimes the most impressive innovation isn't the newest technology - it's knowing when and where to apply the proven one. Spirals won't solve every copper processing challenge, but for fines, oxides, and pre-concentration, they're an elegant answer.

Simple. Effective. Profitable.

For information on the subject, contact Multotec. You can watch the complete webinar here.