Determination of total sulfur content of sedimentary rocks by a combustion method

Total sulfur has been determined in common sedimentary rocks by a combustion method. Sulfur contents range from 0.001 to 5.0%. Experiments show that the combustion method can be used in analyzing sedimentary rocks in which sulfur is present as sulfide, sulfate, or both. Pulverized samples from 0.100 to 0.500 gram in weight are used in this method. Each sample is placed in a No. 6 Leco combustion boat and covered with two fluxes: 0.50 gram of standard ingot iron and approximately 1.0 gram of 30-mesh granular tin. The boat with sample then is placed in the combustion tube of a Burrell Unit Package Model T29A tube furnace which is controlled at a temperature of 1310° to 1320° C. After the sample has been heated for 1 minute, oxygen is admitted at a rate of about 1 liter per minute. The sulfur dioxide formed is absorbed in a starch solution and is titrated with standard potassium iodate in a Leco sulfur determinator. Thirteen values obtained for National Bureau of Standards standard sample 1a, argillaceous limestone, range from 0.273 to 0.276% sulfur (certificate value 0.27% by calculation).