Oxygen Sensor

Actose® Active Oxygen Sensor

Measurement of active oxygen during the steel making process is of critical importance to ensure a problem free process, ensure that grade specifications are met and to optimize materials and energy consumption. Actose® sensors allow the measurement of active oxygen in the molten steel which in turn enables the parametric evaluation of carbon/aluminium in the melt. The estimate of the carbon% in the BOF process allows steel makers to determine the end of blow and the knowledge of active oxygen allows steel makers to estimate the quantity of de-oxidant to be added. The accurate determination of oxygen content with Actose® sensor in killed steel, enables quick heat turnaround during secondary steelmaking.

The Actose® oxygen sensor is based on a magnesia stabilized zirconia solid electrolyte which transports oxygen ions at the molten steel temperature. The oxygen ions travel between a reference electrode of known oxygen activity and the melt. By measuring the millivolts generated due to this movement of the oxygen ions, the oxygen activity in the steel melt is calculated by the Nernst equation given below:


Emf is the measured electromotive force between the 2 terminals

R  is universal gas constant

T  is the measured melt temperature

n is number of electrons transported

F is Farraday’s constant

aO2 steel   is the oxygen activity of steel

aO2 ref  is the oxygen activity of the reference material

Actose® sensors are designed to robustly, reliably and accurately measure the temperature and active oxygen content in the molten steel. Since the oxygen level in the molten steel is closely linked to carbon/aluminium levels as the case may be, the active oxygen measurements are used in empirical relations to reliably predict the dissolved carbon and aluminium levels in the molten melt.