Frother
- Also known as
- flotation frother, MIBC, frothing agent
A frother is a surface-active flotation reagent that helps create small, stable air bubbles and a froth that can hold mineral particles long enough to be collected. Common frothers include MIBC and polyglycol ethers.
What is a frother?
A frother is one of the core reagents in froth flotation. While a collector works on mineral surfaces, a frother works mainly at the surface between air and water. Frothers are surfactants: they collect at bubble surfaces and change how bubbles form, how they behave in the slurry, and how the froth holds together at the top of the cell.
What frothers do
- Make bubbles smaller. Frothers reduce bubble coalescence, so the air forms many small bubbles rather than a few large ones. Small bubbles provide more surface area for particles to attach to.
- Stabilize the froth. Frothers help the froth layer hold its structure long enough for loaded bubbles to be removed as concentrate.
- Control froth mobility and drainage. The right froth is stable enough to carry particles but drains enough water, and the fine gangue suspended in it, back into the slurry.
Common frothers
- Alcohols, notably MIBC (methyl isobutyl carbinol), which tend to form a more brittle, fast-draining froth.
- Polyglycols and polyglycol ethers, which tend to form a more persistent froth and are often used where coarser particles must be carried.
- Pine oil and cresylic acid, historically important and still used in some operations.
Plants frequently blend frothers to tune bubble size and froth behavior.
Frothers, water recovery and entrainment
Froth behavior has a direct effect on concentrate quality. A froth that is too stable carries more water into the concentrate, and with that water comes fine gangue that has not attached to bubbles at all. This is entrainment, and it lowers concentrate grade. A froth that is too weak collapses and drops particles, reducing metallurgical recovery. Frother type and dosage are therefore tuned together with air rate and froth depth to balance recovery against grade.
Frothers can also carry through to downstream steps. Excess froth can cause handling problems in thickeners and pumps and affect water quality when process water is recycled.
Frothers and Locus biosurfactants
Locus Mining describes its biosurfactant-based reagents as influencing froth stability, froth drainage and entrained water, with the aim of improving recovery while controlling entrainment. Performance is established through structured laboratory and plant testing.
Frequently asked questions
A collector adsorbs on the target mineral and makes it water-repellent so it can attach to bubbles. A frother acts at the air-water surface to make bubbles smaller and the froth stable. Most flotation circuits need both.
MIBC, methyl isobutyl carbinol, is one of the most widely used flotation frothers. It is an alcohol that produces a relatively brittle, fast-draining froth.
Yes. Excess frother can make the froth overly stable, increasing water recovery and entrainment of fine gangue, which lowers concentrate grade, and it can cause froth problems downstream.
Sources
- Wills' Mineral Processing Technology, 8th edition, B. A. Wills and J. A. Finch, Butterworth-Heinemann, 2016
- SME Mineral Processing and Extractive Metallurgy Handbook, Society for Mining, Metallurgy and Exploration, 2019