based on a ratio of iron to arsenic of 1, was added to AS1 until complete dissolution. MgO was then added to the beaker until reaching pH 6, before stirring the mixture for 6 hours. Afterwards, the mixture was filtered using a Büchner funnel assembly under vacuum and Whatman #3 filter paper. 2.4 Glass Formulation Testing Methodology Both glass products were formulated using ACS grade reagents, following the dry-basis recipes described in Table 1. Table 1 – Dry mix composition Raw Material Units Glass 1 Glass 2 From EC1 Pyrolysis Byproduct From AS1 Precipitation Byproduct As2O3 (Flue dust) %wt. dry 26.6 -- As2O3 (Precipitate) %wt. dry -- 45.6 Hematite %wt. dry 14.5 4.10 Sodium Carbonate %wt. dry 16.0 21.1 Silica Sand %wt. dry 38.9 29.2 Alumine %wt. dry 4.7 -- The glass was melted in a Katanax fluxer at 1,200°C for 3 hours using an alumina crucible with 20g of dry mix per glass. 2.5 Arsenic Glass Environmental Characterization – EPA 1311 The US EPA TCLP (Method 1311) is used to simulate contaminant leaching resulting from solid waste in landfills. The appropriate TCLP extraction fluid for the glass product is diluted glacial acetic acid buffered at pH = 4.93 ± 0.05 with sodium hydroxide. Using crushed and sieved pieces glass of sizes between 1.0mm and 9.3mm. For this project, TCLP leaching tests were performed in a specific L/S ratio of 20:1 for a period of 18 hours in 500mL HDPE bottles. The bottle vessels are rotated at 30 ± 2 RPM on a Rotary Agitation Apparatus as shown in Figure 1. After the leaching step, the mixture is filtrated and analyzed for contaminants. (USEPA, 1992). 2.6 Analytical Methods Base metals determination on solids was achieved by di-acid digestion / Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) finish (Perkin Elmer Optima 7300DV). Al, Ca, Fe, Mg and Si contents in solids, as well as Arsenic content in glass were determined by sodium alkaline fusion followed by ICP-OES finish. Gold determination was achieved using crucible fusion / Pb cupellation fire assaying / ICP-OES finish. Total sulfur (LECO S230SH) and total carbon (LECO CS230SH) were determined using elemental combustion analyzers. Particle size distribution (PSD) was determined by laser diffraction particle size analyzer (Microtrac).
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