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i~ <br />Pyrite + O:q~gea + water equals Yellowboy + Sufluric Acid ~~ <br />4FeS2 + 1502 + 14H2O = 4Fe(OH)3 + 8H2SO4 l~ <br />Hydrogen peroxide greatly reduced the time needed for pyrite to oxidize to ` <br />sulfuric acid sad yellowboy. ~~ <br />3,2.11.2 Cosments- <br />Alkaline materials interfere with the efficiency of hydrogen peroxide in ~'~ <br />oxidizing pyrite; therefore, overburden rock sad minesoil samples containing ~ <br />carbonates need to be leached with acid and water ae prescribed in steps <br />2 through 5 of the procedure. <br />When samples contaia readily oxidizable organic matter, step T in the <br />procedure may have to be repeated until the reaction stops. Ir <br />The hydrogen peroxide used in this method moat be 30Z hydrogen peroxide. L ,I <br />It mueL not contain ~tabillzera. i~.. <br />M important thug to remember is that this procedure xorka xith fresh <br />overburden and not with complex mixtures of minesoil material. <br />X2.11.3 Chemicala- <br />1. Silver nitrate (AgN03), lOx: Dissolve 10.0 g of AgN03 with distilled <br />water sad make to a volume of 100 ml. Store in brown bottle away from light. <br />2. Hydrochloric acid (HC1), 2 parts ncid to 3 parts water: Mix 400 ml <br />of concentrated HCl with 600 ml of distilled water. <br />3. Hydrogen peroxide (H2O2), 30x (Fisher certified No. H-325 or equivalent). <br />4, Sodium hydroxide (NaOH), 1.0 N: Dissolve 40.0 g of NaOH pellets in <br />carbon dioxide-free xater (see 3.2.3.3. No. 1) sad make to a volume of 1 <br />liter. Protect from CO2 in air with eacarite tube. <br />5. Sodium hydrozide (ftaOH), 0,1 N: Dilute 10 ml of 1.0 N NaOH to a <br />volume of 1 liter with carbon dioxide-free water (see 3.2.3.3. No. 1). <br />Standardize solution (see 3.2.3.3. Ho. 4). Protect from C02 in air with <br />saca.rite tube. <br />x.2.11.4 Materials- <br />1. Sample, ground to peas s 60 mesh sieve. <br />2. Funnels. <br />3. Hotplate. NOTE: Huneen burner may be substituted. <br />4. Thermometer, °C. <br />70 <br />