Clean TeQ Water’s continuous ion exchange technology provides highly efficient extraction and purification of a range of metals from slurries and solutions
The mining and mineral processing industries use a range of processes for metal recovery from leached solutions and slurries. Ion exchange is a common hydrometallurgical processes used, and is well suited for recovery of low to moderate concentration targets from complex liquors.
Traditional batch or fixed bed ion exchange often produces a low quality metal solution product that requires downstream purification and concentration, with low ion exchange efficiency and high reagent consumption. These systems can also experience issues during upstream process upsets, including increases in suspended solids concentrations. Clean TeQ Water’s CLEAN-IX® technology aims to overcome these issues while providing customers a range of additional benefits.
Clean TeQ Water’s CLEAN-IX® technology provides highly efficient extraction and purification of a range of metals from slurries and solutions. CLEAN-IX® is a combination of continuous ion exchange and counter-current ion exchange, where the resin and slurry/solution are continuously moved around the system, and are directly contacted in countercurrent to each other. This achieves an extraction rate of typically more than 98% of the contained metal in the solution, and provides an economical method for recovery and concentration of dilute streams.
Clean TeQ Water’s metal recovery technologies achieve very high eluate concentrations. We provide customised flowsheets for our clients, with each ion exchange process step occurring in a dedicated vessel which is optimally sized for its task. We provide turn-key metal recovery solutions for customers and can integrate seamlessly into existing processing circuits where required.
By carefully selecting the resin used as part of CLEAN-IX® continuous ion exchange, a range of different metals can be recovered, including those highlighted in the periodic table below.
Uranium Recovery Using U-shaped Moving Bed Desorption Column
Since its first deployment in the late 1980s, desorption of SBA-type resin in a U-shaped moving bed column has become the standard flowsheet in Kazakhstan for processing low-grade uranium leachates at in-situ recovery operations. Wider use of the U-shaped column for desorption of other metals was not implemented within the former USSR, primarily due to limited information exchange between critical elements (uranium, tungsten, etc.), gold and base metals industries.
The key benefit the U-shaped column provides over other styles of desorption columns is its ability to produce eluates with exceptionally high concentrations. This concentration effect is typically accompanied by partial purification and near-stochiometric reagent consumption. The concentration effect occurs due to the presence of various “zones” in the U-column, as presented in the figure below:
As the resin moves through the column, it first encounters the “loading/scrubbing zone from the purge leg”. Here, dilute desorbing reagent exchanges for low-affinity impurities and/or, due to contact with eluate, the targeted metal (e.g. uranium) crowds off lower affinity impurities (e.g. iron and thorium anionic species). The resin exiting the loading/scrubbing zone is enriched in the targeted metal and depleted in impurities.
The resin then encounters the “desorption zone in the desorption leg”. Here, contact with concentrated eluant occurs, and desorption takes place. The counter-current flow of resin and eluant results in a low residual resin phase metal concentration.
U – Column Pricing
It is recognised that the U-shaped column is a larger, more specialised vessel than a typical fixed bed ion exchange column. The cost of such a vessel needs to be considered against the benefits / additional processing opportunities. The price of the standard U-shaped column described in Table 1 is in the range of USD 380 – 480 ex. works (indicative price, which will vary depending on the material of construction selection).
|Resin throughput Capacity||5.0 - 7.5 m3/h (for desorption of chelating resin)|
|Eluant Capacity||Not a constraint, but typically 6 – 10 m3/h|
|Total Resin Volume||~60 m3|
|Working Height||Individual leg height ~11 m, overall length ~26 m|
|Overall Height||~17 m|
To learn more about the moving bed ion exchange desorption for base metals processing and U-column method use the link below.
Advantages of CLEAN-IX®
OPTIMAL METAL LOADING
CLEAN-IX® offers the following advantages during adsorption of metals onto the ion exchange resin:
- Optimal loading of the ion exchange resin and full utilisation of its capacity, since the resin and slurry/solution move in counter-current to each other.
- High tolerance to suspended solids in the feed and easily handling of upstream process upsets since the ion exchange resin is moved around the system
- Resistance to bed fouling as the resin in periodically advanced
CLEAN-IX® offers the following advantages during desorption of metals into a concentrated solution:
- Highly concentrated elates, providing superior water balance and smaller downstream circuits
- Lower operating cost as close to stochiometric consumption of reagents is achieved
- Allows for direct precipitation, crystallisation or EW
- Tolerates precipitation formed during desorption without blocking up
Our continuous counter-current approach can greatly reduce the pay-back period of scavenging circuits, providing end users extra revenue from dilute sources, such as acid mine drainage, tailings water, pit water and a range of mining or industrial wastewaters.
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