The thickness of the froth layer directly affects the recovery rate and concentrate grade. In flotation operations, the thickness of the froth layer is adjusted by the pulp gate of the flotation machine. Reagents and their mass fraction also affect the froth layer thickness.
In the flotation machine, the thicker the froth layer, the more metal is accumulated; the thinner the froth layer, the less metal is accumulated. A certain thickness of the froth layer is beneficial for enhancing secondary enrichment and improving concentrate grade. It is important to prevent the froth layer from becoming too thick, because if the froth layer is too thick, the upper bubbles become larger, reducing the total surface area, and some coarse particles or difficult-to-float mineral particles that have already floated will fall off the bubbles. It is also important to prevent the froth layer from becoming too thin, as this not only weakens the secondary enrichment process but also makes the pulp more easily scraped away, affecting concentrate quality.
In the fine beneficiation process, a thicker froth layer is required to ensure high-quality concentrate; in the roughing and scavenging processes, a thinner froth layer is required to ensure that minerals with poor floatability and some intergrowths are recovered as much as possible.