Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Recovery of precious and base metals from industrial liquors using electrochemical ion exchange

Electrochemical ion exchange (EIX) is an advanced ion exchange process for the treatment of liquid effluent. Research was carried out to establish whether or not EIX is an appropriate technology for the treatment of a range of non-nuclear process liquors. Work was carried out in the following areas:
analysis of industrial process liquors (10 typical waste liquors were analysed and in several cases, the results obtained deviated from the estimated compositions);
screening of existing sorbents from ion exchange (IX) behaviour (acids, oxides, phosphates, and hexacyanoferrates were screened, for their ability to remove the elements of interest and efficient sorbents were identified for several of the selected elements);
laboratory-scale preparation of novel sorbents (both weak organic bases and hydrous metal oxides were prepared);
screening of novel sorbents for IX behaviour (both of the weak organic bases performed well under IX conditions);
investigation of ion fixation mechanisms (fixation mechanisms vary according to the type of sorbent);
large scale preparation of suitable sorbents;
manufacture of prototype EIX flowcells;
manufacture of EIX electrodes;
testing of EIX electrodes with simulant solution including cationic copper, iron, nickel and zinc, anionic arsenic, selenium and chromium, and anionic platinum.
testing of EIX electrodes with genuine process liquors including dilute aqueous solutions containing low levels of platinum, iridium, palladium, arsenic, selenium, chromium, spent process liquors containing low levels of platinum, iridium, palladium, arsenic, selenium, chromium and high levels of salt, waste waters containing base metals, treatment of dilute solutions containing base metals and water softening;
mass transfer of measurements and process modelling the following 6 parameters were studied, in order to assess the performance of the flowcell: (flow rate, current density, feed concentration, feed pH, electrode gap (between the 2 half-cells) and membrane gap (between the EIX membrane and the counter electrode) were studied and a large amount of experimental data was generated);
cell design and operating strategies;
project management.


Pauline ALLEN