Clean-iX® (Metals Recovery)
Multotec offers continuous counter-current ion exchange technologies for mines and mineral processing plants. Our ion exchange technologies are used to isolate a range of metals and treat process water efficiently and reliably, for optimum plant water performance and lower overall costs.
Our continuous counter-current technology is the optimum approach to ion exchange because it allows a continuous flow of water through a moving bed, as opposed to a batch treatment process. This saves you time and reduces resin usage through a more efficient concentration gradient, achieved through the integrated absorption, desorption and washing column design.
In addition to this leading range of chemical precipitation technologies, Multotec also support clients with complete aftersales and technical support, including laboratory and test work services.
Multotec ion exchange technologies are used by mines and mineral processing plants to efficiently treat process water for reuse as well as recover valuable trace minerals. They can also be used to treat acid mine drainage, as well as help plants work towards Zero Liquid Discharge (ZLD).
Continuous Ionic Filtration® (CIF®) is used to improve performance and lower overall costs of a plant’s process water treatment requirements. CIF® is ideally suited for:
The moving packed bed on CIF® works as an ion exchange filter, negating the need for pre-treatment prior to using Clean-iX, and the treatment solution allows for suspended solid and dissolved ions to be removed simultaneously. An optimised resin inventory means a smaller footprint, and high water recovery with low brine volumes is achieved. Additional benefits include:
Clean-iX® achieves higher product purity and high product recovery and is the ideal solution for selective metals recovery. Clean-iX® is available in several configurations as required by your application:
In the ion exchange process, ions between a solution and an ion exchange resin (either anionic or cationic) are exchanged (cation and anion exchange). The process is reversible, which means the resin can be regenerated for reuse, and is used in industrial applications to achieve water softening.
Ion exchange resins consist of polymer beads that are chemically engineered to suit specific ion exchange reactions. These are moved in the opposite direction to the water flow, encouraging them to exchange pre-loaded ions with the targeted ions.
For example, in the adsorption column cation exchange resin beads with H+ ions surrounding their surfaces enter the exchange column from the top. These begin replacing the dissolved metallic ions in the contaminated water. As the water rises up the column and through the resin, its contamination is greatly reduced and the resin’s contaminating ion load increases as it sinks.
The loaded resin exits the adsorption column at the bottom and is moved to a desorption column. A reagent (typically sulphuric acid for cation exchange) is added to the column and agitated using air. The acid in this example removes the metal ions from the resin (e.g. Ca2+ ions) and replaces them with H+ ions from the acid. Once in solution, these ions immediately react with SO42- ions to form e.g. CaSO4 (gypsum), which precipitates as a solid.
The solution is passed over a screen to remove the solid particulates, while the resin, which is now regenerated with H+ ions, drops into the wash column where it is washed via fluidisation before being transferred back to the loading column, completing a continuous transfer cycle.
One of the main advantages of continuous ion exchange system using resin for water treatment is an improved resin inventory. By increasing the concentration gradient in your absorption column and rotating the pockets, the volume of resin required is significantly reduced. This helps to curb the cost of resin in your ion exchange technology, automatically reducing the capital investment with regards to resin expenditure.
Multotec’s laboratory test work for mine effluent purification includes a 1 m³/hr two-stage test rig, which is used for piloting the Clean-iX® and CIF® technologies. Bench scale and laboratory scale test work are also provided, and Multotec is conducting test work on ion exchange and precipitation.