Continuous circuit coprecipitation of arsenic(V) with ferric iron by lime neutralization: Process parameter effects on arsenic removal and precipitate quality

Modeling the Key Lake uranium mill's bulk neutralization process using a pilot-scale model

“…6c) reflect L1 and L2 samples scanned with the 514 nm laser and L2 and KL1 samples scanned with the 785 nm laser. The L1 and L2 Se-Mo spectra from the 514 nm laser shared four broad bands representative of FH, As and SO 4 2− -adsorbed FH, and possibly FA De Klerk et al, 2012;Jia et al, 2006). The AsO 4 3 − band in L2 is not observed in this spectrum, possibly because the As concentration was half than that observed in L1.…”

“…Due to the potential environmental impacts of EOCs, research efforts have focused on defining the mineralogical controls in the tailings body. The mineralogical controls on tailings deposited in the DTMF, and in other U tailings management facilities in Saskatchewan, are dominated by gypsum (CaSO 4 ·H 2 O), 2-line ferrihydrite (FH), Mg-Al hydrotalcite, Al oxides, and poorly crystalline scorodite, among other minor secondary mineral phases that adsorb and/or precipitate EOCs (De Klerk et al, 2012;Essilfie-Dughan et al, 2013;Gomez et al, 2013;Mahoney et al, 2007;Moldovan and Hendry, 2005;Moldovan et al, 2003;Shaw et al, 2011). While several of these mineralogical controls are well understood, minor changes to the ore and milling process could affect EOC sequestration in the tailings.…”

Effects of Additional Layer(s) on the Mobility of Arsenic from Hydrothermally Altered Rock in Laboratory Column Experiments

“…Longer water residence time allows more time for water to dissolve Fe from the dissolvable phase (e.g., Fe 2 (SO 4 ) 3 ) and precipitate as Fe oxy-hydroxide/oxide, producing H + as a by-product. This might be the result of a very low amount of As leaching in cases 2 and 3 due to the following reasons: the first is that these precipitates have high adsorption affinities toward As (Safiullah et al 2004;Tabelin et al 2012a), the second is that As can also be co-precipitated with Fe oxy-hydroxide/oxide (Klerk et al 2012;Ruiping et al 2007), and the third is that the higher amounts of these precipitates result in a lower pH, which also enhances the As adsorption.…”

Disposal of Concentrated Arsenic Rejects

“…In several studies, an attempt has been made to simultaneously separate arsenic from water and to stabilize in the precipitate [25][26][27][28][29][30][31]. In the majority of cases, ferrous and ferric compounds are produced in such chemical precipitation processes.…”