Sustainable optimization of flocculation processes for enhanced solid–liquid separation in mining: influence of operational and physicochemical parameters

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Résumé

This research focuses on optimizing solid-liquid separation at the Yaramoko-Bagassi gold
mine (Burkina Faso), operated by Soleil Resources for US$135 million. The plant processes 1,400
t/d of ore (reserves > 1 Mt at 6.6 g/t) for an annual production of 100,000 to 120,000 ounces of gold.
The study aims to stabilize sludge settling in the thickener, which is disrupted by the alternating mixing
of oxidized ore and fresh rock. Four anionic flocculants supplied by Nowata BF were tested using JarTest on two 15% solids blends: Blend 1 (66.67% oxides / 33.33% fresh rock) and Blend 2 (50% oxides
/ 50% fresh rock). Sedimentation performance measured after 45 seconds reveals the following: On
Blend 1 (highly oxidized): The new flocculant DP 9629 - 2024 consistently outperforms the others. Its
sedimentation rate reaches 71.42% at 15 g/t, 80.00% at 20 g/t, and peaks at 91.42% at 25 g/t. In
comparison, the original product (Plant - DP 9629 - 2020) shows sedimentation rates of 57.14%,
74.28%, and 88.57%, respectively. Flomin AN 913 achieves the lowest results (from 40.00% to
74.28%). Regarding Blend 2 (mixed): At a dose of 15 g/t, the kinetics reverse in favor of Flomin TFA
934 SH (X1), which becomes the most efficient, surpassing DP 9629-2024. In conclusion, the
mineralogy dictates the separation efficiency. The document validates the existence of an optimal
dosage (the supernatant clarity level improving significantly at 25 g/t for Blend 1) and confirms the
overall structural superiority of DP 9629-2024 over highly oxidized ores

Mots-clés

Flocculation; Polymers; Solid-liquid separation; Jar testing; Mining industry