3. RESULTS 3.1 Pyrolysis Approach on EC1 Results Successful removal of the arsenic was demonstrated using pyrolysis treatment the EC1, achieving 99.6% As removal. Table 2 summarizes the main contents of the concentrate before and after pyrolysis. This approach produced a residue which is depleted in arsenic and has a higher valuable metals grade. Table 2 – Pyrolysis approach characterization and results Sample Sample Type As Cu Stotal Au As removal Mass loss %wt. %wt %wt g/t % % EC1 Enargite Concentrate 15.1 45.5 36.4 6.10 99.6 34,2 EC1-PYR Pyrolysed EC1 0.11 63.0 25.3 15.2 After 400g of concentrate was pyrolyzed, a mass of 60.7g of As₂S₃ was collected in the dust-collectors. The by-product contained 38.6 %wt. As and little to no other base metals contamination (less than 1 %wt. total). This As₂S₃ by-product was then oxidized entirely to form 41.05g of As₂O₃, for which composition is shown in Table 3. This As₂O₃ by-product was then directly amenable to vitrification as described in sections 2.4 and 3.3. Table 3 – Arsenic trioxide (pyrolysis by-product) characterization. Sample Sample Type As content Cu Stotal %wt. (%wt) (%wt) EC1-PYR-AS2O3 Arsenic trioxide from pyrolysis 72.85 ≤40 0.1 3.2 Precipitation Approach on SB1 Results Iron-based precipitation at pH 6 was highly effective for arsenic removal. As shown in Table 4, it allowed to deplete arsenic from the acidic solution. Table 4 – Initial sample and cleaned solution characterization. Sample Sample Type As As removal FeCl addition MgO addition mg/L % g/L g/L SB1 Arsenic-bearing acid 8,620 99.9 18.07 17.0 SB1-Clean Neutralized SB1 7.14
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