Hydroxamic acid polyacrylamide (HAPAM) is an advanced, functionally modified polymer increasingly applied in copper ore beneficiation, particularly in flotation systems involving complex, low-grade, or oxidized copper ores. By incorporating hydroxamic acid groups (–CONHOH) into the polyacrylamide backbone, HAPAM combines chelating ability, polymer bridging, and surface modification, making it highly effective in improving copper recovery, selectivity, and process stability.

Below is a detailed and structured explanation of the application of hydroxamic acid polyacrylamide in copper ore beneficiation (≈980 words).

1. Background: Challenges in Copper Ore Beneficiation

Copper ores are broadly divided into:

• Sulfide ores (chalcopyrite, chalcocite, bornite)
• Oxide ores (malachite, azurite, chrysocolla)

Modern copper beneficiation faces several challenges:

• Declining ore grades
• Increased proportion of fine and ultra-fine particles
• Complex mineral associations
• Presence of clay and slime coatings
• Difficulty in floating oxide copper minerals

Traditional collectors such as xanthates work well for sulfide ores but are less effective for oxide ores. This is where hydroxamic acid polyacrylamide provides significant advantages.

2. Chemical Mechanism of HAPAM in Copper Systems

The performance of hydroxamic acid polyacrylamide is based on three key mechanisms:

2.1 Chelation with Copper Ions

Hydroxamic acid groups exhibit strong coordination ability with metal ions such as:

• Cu²⁺
• Fe³⁺
• Al³⁺

In copper systems:

• HAPAM forms stable complexes with Cu²⁺ on mineral surfaces
• This enhances selective adsorption on copper minerals