WaterSolutions Separation of Copper from Liquid Media

Mining and Mineral Processing: For nearly three decades, solvent extraction (SX) has been the predominant and most economic method of copper recovery in mining applications. It is an inexpensive and efficient way to extract and recover copper from high grade oxide ore deposits. While solvent extraction processes are excellent for high grade ores producing pregnant leach solution (PLS) grades greater than about 1.0 gr/L, a special chelating resin from Dow provides an avenue to low cost hydrometallurgical processing of lower grade PLS feed streams. This resin based process may be excellent for the processing of tailings dump material as well as in the decommissioning of spent copper heaps and dumps. Calgon Carbon completed pilot testing and has published its results (2.2MB PDF).

Using a special Dow resin, very high purity cathode copper can be produced even without electro-refining. We are aggressively developing resin-based copper recovery technology specifically suited for the copper mining industry. For a printed copy of a recent publication on our current efforts please contact Gordon Rossiter of Rossiter Enerprizes. A chelating resin based process could overcome the several drawbacks of liquid-liquid solvent extraction processing:

• Huge quantities of potentially flammable organics must be handled in the open air.
• Disposal of large quantities of hazardous liquid organics may pose a serious environmental and safety problems in the future.
• Leach solutions containing suspended solids are unsuitable for solvent extraction.
• Poor economics for low grade PLS

Acid Rock Drainage (ARD): DOWEX™ M4195 chelating resin may be an ideal choice for many ARD applications. This resin's extreme selectivity for copper, along with its high removal efficiency (effluent streams have extremely low concentrations of copper, even at very low pH), makes it an useful tool for ARD management.

Plating: Copper is often a problem metal in precious metal and trivalent chromium plating operations. The distinct ability of DOWEX M4195 chelating resin to selectively adsorb copper (II) from strongly acidic media makes it perfect for applications like removal of copper from trivalent chromium baths and from bright-dip rinse applications in aluminum finishing processes. At very high acid concentrations, copper can sometimes be captured as an anionic coupler (42KB PDF) using a strong base anion exchange resin such as DOWEX 21K XLT resin.

Printed Circuit Boards and e-Chips: Current technology for high speed data chips incorporate copper conductors. Several chip manufacturers have already discovered the phenomenal selectivity, capacity, and acid processing capability of DOWEX M4195 resin, making it well suited for this application area.

Water/Wastewater: Removal of copper from water and organic solvents is fairly common using strong acid cation resins. For waters with low levels of salt content a strong acid cation resin such as DOWEX G-26 (H) resin would be a good starting point. In addition, weakly acidic cation exchange resins like DOWEX MAC-3 resins are often quite selective for multi-valent ions such as Cu (II). If the wastewater is highly acidic, DOWEX M4195 chelating resin is a resin-of-choice.

References

1. Copper Recovery from Leach Liquors Using Continuous Ion Exchange, Gordon J. Rossiter and Kenneth C. Carey, Proceedings of Copper Hydromet Roundtable 98, Randol, Vancouver.

2. Ammoniacal elution of copper from ion exchange resins, Byleveld, Edward, Patent US4371506, Hemsley Engineering Ltd.