We work with you develop the SX-EW bench tests, solvent extraction piloting and flowsheets that enable you to recover maximum pay metal while meeting environmental, health and safety regulations. SGS metallurgists have the expertise and experience to develop the process parameters that yield maximum recovery.
SX-EW (solvent extraction and electrowinning) are distinct metallurgical unit operations that recover high purity metal from leachate solutions. Solvent extraction is used to concentrate materials in an organic solution, while electrowinning is used to recover these pay elements. The two procedures are often conducted together. While electrowinning can be used with other processes, it is always used after solvent extraction.
Many elements can be extracted from aqueous metal-rich leachate solutions and concentrated into an organic solvent. The pay elements are then removed from the organic solution by electrowinning. The resulting high purity metal plate is then directly sold.
SGS has proven experience recovering a number of elements through SX-EW including:
- Gold and silver
- Copper (from sulfate and cyanide solutions)
- Nickel (including nickel laterite)
- Cobalt and zinc
- Zirconium and rare earth elements
- Manganese and vanadium
- Niobium and tantalum
SGS Solvent Extraction and Electrowinning services include:
Technical Operations
SGS metallurgical experts can recover a wide range of metals from leach liquors and other solutions. Our bench testing capabilities that support flowsheet development or plant troubleshooting include:
- Determination of phase disengagement and separation times
- Chemical and physical organic scrubbing studies
- Evaluation of physical properties (densities and viscosities)
- pH profiles that determine effect of pH on metal distribution
- Effect of reagent concentration, temperature and phase continuity
- Evaluation of maximum loading and effective organic reagent concentration
- Determination of kinetics (extraction and stripping)
Solvent Extraction and Electrowinning Pilot Plants
SGS custom designs pilot plants to prove flowsheets. We provide pilot design and testing services.
Our solvent extraction equipment includes mixer-settlers, columns, contactors, coalescers, reciprocating plates and contacting units. As well, we have electrowinning cells, power supplies and electrode materials for use as stand-alone electrowinning units or with SX or similar circuits. Our cells can be equipped with temperature control and electrolyte recirculation systems when necessary.
Other SGS SX-EW Services
SGS provides a number of other services for the ongoing support of SX-EW including:
- Design, specify and build custom cell configurations in materials selected for resistance to process chemistry conditions
- Assembly and transfer of modular pilot plants to remote sites
Key features of SGS’s SX-EW capabilities
- SGS maintains an extensive inventory of major solvents, extraction reagents, diluents and modifiers including oximes, amines and phosphoric acids and guar gums. We have the expertise to test the effectiveness of all reagents currently available and provide an independent recommendation of the optimal reagent for your operating conditions
- Dedicated analytical support on-site leads to faster turnaround times. This allows controlled and informed decisions during piloting
- ABB process control systems that acquire key operating data during piloting including pH, temperature and cell voltage. This operating system agreement ensures real-time systematic record keeping
Solvent extraction and electrowinning are industry-proven metal recovery unit operations that SGS can include in metallurgical flowsheets. They typically generate LME-grade metal products that can be sold directly to the market. SX-EW flowsheets designed and tested by SGS improve cash flow and ensure safe, compliant plant operations.