Control of Slimes in Problematic Ores: Selective Cu/Au/Ag Mineral Separation

S. Murthy KhandrikaColumbia UniversityCytec Industries, Inc.

Center for Particulate & Surfactant Systems (CPaSS)IAB Meeting New York, NYAugust 2009

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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)4O10(OH)8

• Talc: Mg3Si4O10(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

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EDX data:Value mineral (Cu) content very lowLarge quantity of altered silicates presentChallenge is to selectively separate value mineral (Cu)

COMPLEX COPPER ORE CONTAINING ALTERED SILICATES

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keV

Talc ?

Mica ?

EDX data shows possible presence of talc or mica.Fibrous mineral also noticed.

keV

EDX spectrum

EDX spectrum

Carboxy methyl cellulose

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MODIFIERS

Cyquest 40E

COO -SO-3COO -

Some of the functions of a modifier:Dispersion of slimes

Prevention of heterocoagulationViscosity reduction

ONE POSSIBLE MECHANISM OF MODIFIER OPERATION

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Cu

Cu Cu

Cu 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

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EFFECT OF MODIFIERS ON Cu AND Au RECOVERIES

Copper and gold recoveries improved upon using modifiers

Copper Ore 2

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Polymer : 150 g/tpH: 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

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Mineral particle-reagent interactions R&DImpact

Knowledge-base: ParticlesDispersionSolution chemistry Reagents

Applications:PharmaceuticalsCosmeticsDrillingMineral ProcessingFoodPulp & Paper

Further develop: New reagentsGreener, 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

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ACKNOWLEDGEMENT

Cytec Industries, Inc.

Newmont Mining Corporation

Vale Inco

THANK YOU