6.9.1 Gas Analysis

Gas analysis is done either by an Orsat type analyzer or infrared analyzer. In the Orsat type the complete analysis of a gaseous mixture is divided into the absorption phase and the explosion or burning phase. The amount of carbon dioxide, oxygen and carbon monoxide are determined by chemical absorption. These units are portable and permit relatively rapid analyses.

The infrared analyzer depends on the principles that different gases absorb infrared energy at characteristic wave lengths. Because of this property, changes in the concentration of a single component in a mixture, produce corresponding changes in the total energy remaining in an infrared beam passed through the mixture. Proper selection of apparatus permits accurate, rapid analyses for such constituents as carbon monoxide, carbon dioxide and methane. Such analyzers are not suitable for measuring oxygen, hydrogen and nitrogen which have no infrared absorption band. Such analysers are highly sensitive and are successfully applied for analyzing gases with high carbon potential, such as purified exothermic gas or dry endothermic gas, and those with high purity such as dry hydrogen or argon.

6.9.2 Specific Gravity Analysis

The specific gravity of gases can be measured and compared against that of air. Since carbon dioxide is much heavier than the other sintering atmosphere constituents, this analysis is especially sensitive to changes in carbon dioxide. In case carbon dioxide appears in the influent or effluent furnace atmosphere, the specific gravity analyser could be used for corrective measures. This...