Typical process liquors were analysed. Several novel sorbents were synthesised. Existing and novel sorbents were screened for their ability to remove the elements of interest (Cu, Ni Zn, As, Se, Cr, Pt, Ir, Pd). Promising materials were incorporated into EIX electrodes and/or membranes. These were tested in prototype EIX (flow) cells. In parallel, mass transfer measurements and process modelling led to improvements in the flowcell design. Tests were conducted using simulant solutions and genuine process liquors. Good results were obtained for all these types: base metal cations, base metal anions, and precious metal anionic complexes. In the last year of the project, the Work Programme was modified to include continuous EIX (developed in a separate programme). In the limited time available, most encouraging results were obtained for the base metal cations and the precious metal anionic complexes.
EIX is an energy efficient process which requires few added chemicals. It enables valuable metals to be recycled and toxic metals to be removed. The project has generated significant data on a wide variety of aqueous solutions. This will put us in a good position to design customised EIX plant for the treatment of specific process streams containing precious and/or base metals.
Electrochemical ion exchange (EIX) is an advanced ion exchange process for the treatment of liquid effluent. Absorption of ions is controlled by an externally applied potential. Elution is achieved by polarity reversal - no eluant chemicals are required. To date, applications of EIX have been limited to the nuclear industry. Other potential applications include recovery of precious metals and removal of base metals from waste water. This project will establish whether EIX is an appropriate technology for these non-nuclear problems.
Proposal research includes analysis of various proxess liquors, synthesis of suitable sorbents, and testing of EIX electrodes with simulants. In paralell, measurement of mass transfer and modelling studies would allow design of an improved flowcell. Existing prototype cells and any improved version would be tested by the end user, using real industrial effluents and low level precious metal liquors.
The first industrial partner runs a precious metal refinery and manufactures electrochemical process equipment, whilst the second industrial partner manufactures mineral ion exchangers for treatment of industrial effluent. They are supported by two Research Centres and two Universities. The partners possess the required skills and facilities to carry out this work in a complementary action.
Funding SchemeCSC - Cost-sharing contracts