106.3.2.92.1 Scope

This method determines sulfide sulfur by oxidation of sulfide sulfur to sulfate during the Loss on Ignition (LOI) test. The LOI ignited material is tested for SO3, subtracted from the initial SO3 and divided by a factor to calculate sulfide sulfur.

106.3.2.92.2 Summary of Method

The initial SO3 is determined by the acid filtrate during the insoluble residue test. The acid filtrate is diluted to the 250-ml mark in a 400-ml beaker, heated close to boiling and 10-ml of 10% barium chloride (BaCl2) is added to the 400-ml beaker. Ba...

106.3.2.92.3 Equipment and Reagents

106.3.2.92.4 Procedure

Weigh 1 gram +/- 0.0005 of sample into a 250-ml beaker. Add an initial 25 ml of DI water, use stir rod to disperse sample, add 5 ml of concentrated HCl and a final 20 ml of DI water for a final volume of 50 ml. When adding acid to the sample, make su...

106.3.2.92.5 Calculation

As received SO3, %: weight of BaSO4 x 34.3 = initial SO3 SO3 after ignition, %: weight of BaSO4 x 34.3 = final SO3 34.3 = molecular weight of SO3/molecular weight of BaSO4 x 100 Sulfide = final SO3 - initial SO3/2.35 2.35 = molecular weight of SO3/molecular weight of H2S