Ultra-Fine Mineral Separation – Unlocking Hidden Value
Currently, mineral processing operations have reached a high level of automation and standardization in the definition of process routes. Advanced computational tools, based on orebody mineralogy, are widely used to design efficient flowsheets using well-established operational parameters and equipment already proven at industrial scale.
However, structural challenges still remain. In particular, high-grade ores often generate tailings that are also rich, but composed of ultra-fine particles that fall below the recovery limits of conventional processing technologies currently available in the market. As a result, mineral fractions with significant metallic value remain unrecovered, negatively impacting the overall yield of mining operations.
These challenges are directly analogous to those faced by HpM in the regeneration of steelmaking residues. As in mineral tailings, industrial residues exhibit high metallic content, but in the form of fine particles, strongly aggregated among themselves or associated with undesirable phases. This condition demands separation techniques capable of promoting selective liberation without inducing further particle size reduction.
Throughout multiple stages of comminution and processing, ultra-fine particles tend to acquire residual electrostatic charges. Even when they appear to be mineralogically liberated, these electrostatic forces promote entrainment between valuable minerals and gangue, significantly reducing the efficiency of conventional separation methods as particle size decreases.
The HpM CVB-SR (Sludge Reactor with Micro- and Nano-Scale Vacuum Bubble Generation) was specifically developed to operate within this critical regime. The controlled action of micro- and nano-scale vacuum bubbles promotes the dissipation of residual electrostatic charges and completes the liberation of partially aggregated particles. As a result, well-established mineral processing techniques — such as flotation, centrifugation, and magnetic separation — recover their operational efficiency even within particle size ranges traditionally considered non-recoverable.
The application of this approach enables increases of up to 15% in the overall yield of mining operations, through the selective recovery of ultra-fine fractions that, in conventional flowsheets, are typically sent directly to tailings.
Ultra-Fine Minerals Recovery from Iron Ore Tailings
Rougher Phase
Cleaner Phase
(A) Tailings "in natura"
600x magnification
(B) Tailings "in natura"
1,200x magnification
(C) Dislimed Tailings
600x magnification
(D) Dislimed Tailings
1,200x magnification
(E) Tailings after Cleaner Phase
600x magnification
(F) Tailings after Cleaner Phase
1,200x magnification
(G) Tailings Concentration
600x magnification
(H) Tailings Concentration
1,200x magnification
The images above illustrate iron ore tailings traditionally directed to tailings dams. Despite their high iron content, these materials are not recovered through conventional beneficiation routes due to their ultra-fine particle size and strong mineral–gangue aggregation.
Images A and B show the tailings in natura at two different magnifications, highlighting the highly aggregated nature of the particles. Images C and D present the same material after treatment in the HpM CVB-SR (Continuous Vacuum Bubble Sludge Reactor) followed by desliming. A clear increase in mineral liberation can be observed, with reduced particle agglomeration and improved separation between valuable minerals and gangue phases.
Images E and F show tailings from the Rougher stage subjected to the Cleaner phase prior to concentration. Finally, images G and H display the same material after gravitational concentration, evidencing the effective upgrading of the ultra-fine fraction.
Iron ore tailings frequently contain significant amounts of valuable iron-bearing minerals that remain unrecovered due to their ultra-fine particle size. HpM’s CVB-SR technology enables the selective liberation and recovery of these ultra-fine fractions, restoring the effectiveness of conventional mineral processing routes and converting previously discarded tailings into valuable resources.