When choosing between a Falcon gravity concentrator or a Knelson™ gravity concentrator, many mining operations choose to use a Falcon concentrator if they aim to recover fine gold. Why is that?
Many case studies have shown that the Falcon outperforms the Knelson™ in recovering fine or flaky gold, as encountered in flotation feeds, concentrates, or tails. This is because the falcon is operated at higher rotation speeds than the Knelson™, without fluidizing water. Because of large rotation velocities, the Falcon concentrator lowers both the size of the optimum and minimum recovery below 25μm.
In particular, the batch Falcon is effective in the fine range (less than 37μm for gold). This makes the Falcon concentrator ideal as a preconcentration unit. Let’s look at some of the situations where a Falcon concentrator is used alongside a Knelson™ concentrator in the same plant, to observe the difference in fine gold recovery.

Scavenging Gold from a Flotation Tail – LaPlante Study

In a 1989 LaPlante study, researchers observed an application where very fine gold-bearing pyrite and gold particles were to be recovered from the fine fraction of a flotation tail. Coarse fraction was already cyanided prior to this segment of the experiment.
Testing between both the Knelson™ and Falcon for this case resulted in:

  • Falcon recovery above 30%
  •  Knelson™ recovery well below 10%

Since this study, we have developed new lines of the Falcon concentrator and also improved on existing machines by producing the Falcon Ultrafine (UF) concentrator in addition to the Falcon Semi-Batch (SB) and the Falcon Continuous (C) Concentrator.
Due to the Falcon’s ability to process fine metals in an optimal fashion, this makes our machines uniquely positioned to optimize complex operations. This can be applied to operations outside of gold. For example, one of the world’s largest Tungsten mines located in Northern Vietnam relies on Falcon Concentrators to process their product.
In another example, the C2000 Falcon Centrifugal Concentrators are used in the Renison Tin Operation in Tasmania, where concentrate particles are recovered at a rate of 60t per hour. This is one of the biggest operating tin mines in Australia, with a capacity of 680,000tpa of tin.

Choosing The Right Falcon for Your Operation – Renison Tin

The Bluestone Mines Renison Tin Project, located near the west coast of Tasmania, utilizes both flotation and gravity concentration in its operation. The Renison Tails process flowsheet consists of fine grinding, sulphide flotation, ultrafine (UF) gravity separation, and tin flotation.
The primary gravity concentration circuit consists of spirals, tables and Falcon C2000 Continuous units with the C-Machines processing the reground spiral and table tailings. The ultra-fines from the primary gravity circuit tails are upgraded via flotation followed by final upgrading with Falcon Ulftrafine (UF) concentrators.
It is in Ultra Fine gravity separation where the Falcon Concentrator shines. In addition to the Sepro Batch Falcon (SB) and the Continuous (C) concentrator, the Falcon Ultrafine (UF) concentrator is uniquely suited for ultra-fine industrial and strategic minerals such as tin, tantalum, and tungsten.
In this operation, the Falcon Ultrafine is used in final upgrading. However, Sepro Falcon concentrators have a variety of use cases throughout mineral processing. As the ideal machine for fine gold recovery, you should consider a Falcon concentrator if your operation has the need to recover very fine particles. If you would be interested in speaking with an engineer, you can contact Sepro today to learn more.