OPTIMAL METAL LOADING
Mankind has been using copper for approximately 10,000 years, and its use continues to underpin global economic development. Today however, the combination of high mining costs, increasingly stringent environmental obligations, and exhaustion of historically important metal sources has led to increased interest in recovering marketable copper products from acid mine drainage (AMD), raffinates, and other forms of solid and liquid wastes originating from mining and other industrial activities.
The chemistry underpinning ion exchange enables the selective recovery of copper from such dilute effluent streams, slurries and pulps to bring the residual concentrations down to the regulatory discharge limits. Clean TeQ’s engineering philosophy of continuous counter-current processing then permits these recovered copper units to be readily converted into saleable copper products, thereby off-setting treatment costs, and often providing economically viable copper production in its own right.
Clean TeQ’s approach to ion exchange can enable viable copper recovery from clarified solution concentrations as low as 70 mg/L Cu, depending on the impurity load in the stream (e.g. free acid, soluble iron) and the availability of existing site infrastructure. At such concentrations, dilute streams such as solvent extraction raffinate, acidic mine drainage and pit water can easily become targets for copper recovery.
Clean TeQ can also provide copper recovery from slurries and pulps (e.g. CCD underflow), but the copper concentration at which this typically becomes economically attractive will vary depending on what other value metals of interest may be present.
The ability to recover value from such streams is possible due to the following characteristics of Clean TeQ’s ion exchange technology:
- The moving bed adsorption system provides a natural resilience to entrained suspended solids, which are commonly formed in upstream impurity control steps. This resilience also allows the system to run at the high solution-to-resin ratios required to max-load the resin with copper, all without fear of bed fouling.
- The counter-current elution system provides cost-competitive, near-stoichiometric reagent consumption which can materially reduce the pay-back period of a scavenging circuit.
- Furthermore, efficient elution avoids eluate dilution, making it possible to produce concentrated product liquors of 30 – 70 g/L Cu (as CuSO4), depending on the equipment configuration selected by Clean TeQ. As such, a copper upgrade factor of 500+ is achievable from a dilute feed to the final eluate.
The product liquor from Clean TeQ’s ion exchange circuit is able to feed various existing or new-build downstream circuits to produce a saleable product, including:
- The strong electrolyte stream in existing EW tank-houses;
- Direct EW circuits capable of processing a strong electrolyte, nominally 70 g/L Cu, <10 g/L H2SO4;
- Copper sulfate crystallisers;
- Other copper precipitation circuits, as the application may require.
Where required, Clean TeQ can configure the ion exchange circuit to receive recycle streams which may originate in the downstream circuit (for example, streams such as spent electrolyte or mother liquor).
To help you with your soluble copper recovery challenges, Clean TeQ provides:
- Delivery of lump sum turnkey (LSTK) metal recovery plants, along with commissioning and operations support;
- Metallurgical testwork and flowsheet development, including lab-based and site-based testwork programs, and pilot plant design, fabrication and operation.