Why Coarse Particle Flotation Is Regaining Attention

Traditional sulfide copper flotation generally depends on fine grinding to maximize mineral liberation and bubble-particle collision probability. However, for many large Brazilian copper operations, excessive grinding introduces several operational challenges:

• Higher electricity consumption;
• Increased grinding media and liner wear;
• More difficult tailings thickening and dewatering;
• Higher generation of ultra-fine slimes;
• Reduced water recovery efficiency.

In northern Brazil especially, several large-scale open-pit copper operations are processing increasingly complex ores with higher throughput requirements. Under these conditions, concentrators are focusing more on energy consumption per ton of ore processed rather than pursuing ultra-fine grinding alone.

The objective of coarse particle flotation is not to eliminate fine grinding completely. Instead, it aims to recover adequately liberated sulfide minerals earlier in the process before overgrinding occurs. This approach is particularly relevant for chalcopyrite and other copper sulfide minerals where coarse liberated particles still maintain sufficient floatability.

Coarse Particle Recovery Requires More Selective Reagent Systems

Compared with fine particles, coarse sulfide particles are heavier and have lower surface area-to-mass ratios. As a result, flotation stability becomes more sensitive to bubble strength, froth structure, and reagent selectivity.

Conventional high-frothing collectors often create several operational problems in coarse flotation circuits:

• Excessively thick froth layers;
• Coarse particle detachment from bubbles;
• Increased entrainment of slimes;
• Flotation cell overflow instability.

Because of this, many copper concentrators are shifting toward low-frothing, highly selective dithiophosphate collectors combined with more controllable frothers.

Based on the environment analysis, several reagent systems in Zhejiang Xinyong are particularly suitable for coarse sulfide copper flotation environments.

1. Selective Dithiophosphate Collectors

Sodium diisobutyl dithiophosphate demonstrates relatively weak collecting ability toward pyrite under alkaline conditions while maintaining strong selectivity for copper sulfides. This characteristic becomes especially important in coarse particle flotation systems.

Lower frothing tendency helps:

• Prevent excessively stable froth;
• Reduce coarse particle drop-back;
• Improve froth drainage;
• Minimize slime entrainment.

In complex Brazilian polymetallic sulfide ores, selective adsorption onto chalcopyrite surfaces can improve concentrate quality while maintaining flotation stability.

Similarly, sodium diethyldithiophosphate maintains stable collection performance across relatively broad alkaline pH conditions and provides selective suppression against pyrite. This is highly relevant for high-sulfur copper ores commonly encountered in South American operations.

When excessive pyrite flotation occurs in coarse circuits, concentrate grade may decline significantly while downstream thickening and filtration loads increase. Therefore, selective collectors are increasingly preferred in high-throughput copper flotation plants.

2. Frother Selection Becomes More Critical

In coarse particle flotation, froth structure is equally important as collector chemistry.

According to the product descriptions, M7012 and M7022 frothers feature:

• Stable froth structure;
• Moderate froth brittleness;
• Easy defoaming behavior;
• Strong adaptability to pH and temperature fluctuations.

These characteristics are beneficial for coarse particle transport because coarse particles require stronger bubble carrying capacity without generating excessively persistent froth layers.

The ability to maintain foam stability while allowing rapid foam collapse after discharge can also improve downstream concentration and filtration efficiency.

Why Brazil Is Focusing on “Coarse Particle + Energy Saving” Strategies

Brazil’s mining sector has increasingly shifted from simple capacity expansion toward lower-energy and lower-water-consumption beneficiation strategies.

Public information released by Anglo American Copper highlights that coarse particle recovery technologies can reduce grinding energy requirements while improving overall resource utilization.

For large Brazilian sulfide copper operations, coarse flotation strategies may provide several operational benefits:

• Reduced grinding energy consumption;
• Lower generation of ultra-fine slimes;
• Improved tailings settling performance;
• Better water recycling efficiency;
• Reduced pressure on tailings storage systems.

As environmental regulations and operational costs continue to tighten, future flotation optimization in Brazil will likely involve a combination of:

• Coarse particle flotation design;
• Selective reagent systems;
• Advanced froth control strategies;
• Tailings water recovery optimization.

Rather than functioning as an isolated process upgrade, coarse particle flotation is increasingly becoming part of a broader energy-efficiency and sustainability strategy for modern copper concentrators.