Efficient and selective flotation recovery of chrysocolla via EDA/2-MP synergistic activation: Performance and adsorption mechanism

EDA/2-MP turns inert Cu–O–Si domains into KBX-responsive Cu-organic sites. • EDA unlocks Cu(II) sites for 2-MP anchoring via Cu–N/Cu–S bonding. • A continuous ~30 nm N/S/Cu-rich activation film is visualized on chrysocolla. • Interface reconstruction enables 95% chrysocolla recovery and selective separation. Chrysocolla is one of the most difficult oxide copper minerals to recover by flotation because of its strong hydrophilicity, low reactivity, and poor adaptability to conventional activation methods. In this study, an EDA/2-MP synergistic activation system was developed using KBX as the collector. At pH 10, single-mineral flotation tests were conducted with 38–74 μm chrysocolla at a pulp solid concentration of 10 g/L and a flotation time of 8 min, with three independent tests performed for each condition; an artificial chrysocolla–dolomite mixture at a mass ratio of 1:1 was also used to evaluate separation performance. At EDA, 2-MP, and KBX concentrations of 40, 280, and 60 mg/L, respectively, chrysocolla recovery reached 95.34%. In the mixed-mineral system, concentrate Cu recovery remained above 95%, with a Cu grade of approximately 34%. FIB-TEM revealed a continuous low-crystallinity film approximately 31.2–33.9 nm thick after EDA/2-MP treatment. Raman, XPS, and ToF-SIMS showed that EDA/2-MP altered the chemical environments of surface Cu, N, and S species and promoted the enrichment of KBX-related components at the activated interface. Accordingly, EDA/2-MP pretreatment followed by KBX addition increased the chrysocolla contact angle from 24.52° to 82.65°, confirming surface hydrophobization. This study provides a new selective interfacial activation strategy for efficient flotation recovery of refractory silicate-type oxide copper minerals. Download: Download high-res image (203KB) Download: Download full-size image