Grant: CCI Applied Research and Development Grants

The Centre Technologique des Résidus Industriels (CTRI) affiliated with the College of Abitibi Témiscamingue collaborates with Aldex Chemicals Inc to integrate innovative anionic exchange resin with a potential to treat problematic anions contaminants (nitrate and sulphate) in mine effluents in cold temperature. Aldex Chemical has over 40 years of field usage by thousands of customers demonstrating the reliability of Aldex ion exchange resins, zeolites, and other water treatment media. This proposed project is seen as a continuity for the RDA II funded by NSERC (NSERC- 548770-19 RDA). The results of the previous project obviously showed that anion exchange resin was a viable treatment option for mine effluent for the removal of sulphate. In the context of the previous project (concerning sulphate removal from mining effluent) performed by CTRI with the collaboration of Aldex Chemical, it was found that sulphate can be adsorbed rapidly on the strong base resin. An exothermic reaction was discovered, indicating greater removal/adsorption stage performance in cold climates. On the other hand, doing a number of experiments for resin regeneration showed that the regeneration was not completely successful using the NaOH, HCl, and H2SO4 solutions, as the competing thiocyanate and cyanate anions adsorbed strongly on the resin. To overcome those issues and to develop a feasible process, this proposed project will be divided into three parts; Part 1: A pretreatment for the removal of cyanate and thiocyanate compounds from the effluent of gold mine operation is proposed as a biological approach. Since the conversion of mentioned nitrogen-based compound leads to producing higher nitrate (10 times), these anions (nitrate) need also to be removed. Consequently, a consecutive process is suggested, to first remove the nitrate by nitrate selective resin and then remove sulphate by strong base resin; Part 2: the regeneration of resin and management of the regeneration eluent is critical in the ion exchange resin process. Therefore, in this part, the regeneration for both nitrate-selective resin and sulphate-removal resin will be evaluated. Moreover, the mobility of inorganic species adsorbed on spent resin will be examined. Part 3: The results of the prior phases will be used for economic assessment and scale-up considerations.