Control of Slimes in Problematic Ores: Selective Cu/Au/Ag Mineral Separation S. Murthy Khandrika Columbia University Cytec Industries, Inc. Center for Particulate & Surfactant Systems (CPaSS) IAB Meeting New York, NY August 2009

2 CHALLENGE/GOAL Challenge: Processing problematic ores containing altered silicates and slimes (fines) Goal: To develop a scientific understanding of the above processing problem To develop robust chemical methodology for better metallurgical performance (Cu, Au, Ag)  Hypotheses: Poor separation of desired minerals attributed to: Presence of altered silicate (Mg silicates) slimes (fines). For example, Chlorite: (Mg,Fe,Al) 6 (Al,Si) 4 O 10 (OH) 8 Talc: Mg 3 Si 4 O 10 (OH) 2 Aqueous species generated from these silicates Certain Polymeric Modifiers can mitigate these adverse effects  Objective: Study the effect of functionalized polymeric modifiers in improving selective recovery of value minerals HYPOTHESES/OBJECTIVES

Cu Ca Mg Si COMPLEX COPPER ORE CONTAINING ALTERED SILICATES 3 EDX data:  Value mineral (Cu) content very low  Large quantity of altered silicates present Challenge is to selectively separate value mineral (Cu)

COMPLEX COPPER ORE CONTAINING ALTERED SILICATES 4 keV Talc ? Mica ? EDX data shows possible presence of talc or mica. Fibrous mineral also noticed. keV EDX spectrum

Carboxy methyl cellulose 5 MODIFIERS Cyquest 40E COO - SO -3 COO - Some of the functions of a modifier:  Dispersion of slimes  Prevention of heterocoagulation  Viscosity reduction

ONE POSSIBLE MECHANISM OF MODIFIER OPERATION 6 Cu Value mineral Slimes Modifier No Modifier Simplified operation of a modifier

EFFECT OF MODIFIER 40E ON Cu RECOVERY AND GRADE Copper recovery improved by 15% upon using modifier 40E Copper Ore 1 Cu in ore: 0.04% Au in ore: 1.3 g/t 7

EFFECT OF MODIFIERS ON Cu AND Au RECOVERIES Copper and gold recoveries improved upon using modifiers Copper Ore 2 8 Polymer : 150 g/t pH: 9-10 Polymers contain carboxyl and sulfonate groups Cu in ore: 0.3% Au in ore: 0.81g/t

SUMMARY & CONCLUSIONS Polymeric modifiers Improved value mineral recovery and grade in different ores Effective in concentrating low grade ore Performed better than CMC 9 Mineral particle-reagent interactions R&D Impact Knowledge-base: Particles Dispersion Solution chemistry Reagents Applications: Pharmaceuticals Cosmetics Drilling Mineral Processing Food Pulp & Paper Further develop: New reagents Greener, sustainable technologies

FUTURE PLANS Fundamental and applied studies Identify pathways for adverse effects. Elucidate the mechanisms involved. Spiking experiments on “good” ores. Solution chemistry studies to identify species responsible for lower recoveries. Structure–activity relationships of new modifiers 10 ACKNOWLEDGEMENT Cytec Industries, Inc. Newmont Mining Corporation Vale Inco THANK YOU