CL. Analytics

Infrared analyzers are gradually replacing devices, whose principle of operation is based on coulometric measurement of sulfur and carbon concentrations.

The laboratory is equipped with an SC-144DR (LECO Corporation), which allows simultaneous analyzing of a sample for total sulfur and total carbon. In parallel, the content of “carbonaceous” carbon is determined by coulometry from another sample, and then “organic” carbon is determined from the difference between the total and “carbonaceous” carbon. The sample decomposition method is based on sample roasting in a resistance furnace in the presence of a catalyst (flux agent) in an oxygen atmosphere (purity not lower than 99.7%) and is intended for various types of ore, rock and soil. As a result of combustion, sulphur and carbon contained in the sample are converted to CO₂ and SO₂, respectively. The evolved gases are pumped out of the furnace, dried by the anhydrone and enter the cells where their absorption is measured in the infrared range of the spectrum (on the lines corresponding to the vibrational energy of the C-O and S-O bonds).

SC-144DR Infrared Sulfur and Carbon Analyzer by LECO Corporation

The absorbance measured in the cells is directly proportional to the sulphur and carbon contents, respectively. The analysis is based on the “Determination of the mass fraction of total sulphur and total carbon in samples of ore, rock, soil, bottom and loose sediments, anthracite, brown and hard coal by infrared spectrometry. VSEGEI MP No. 15/2010, third category of accuracy.

Element concentration ranges determined using this technique