Nidesy,a laboratory prototype System for determining nitrogen concentration in metal bath continuously

A laboratory prototype of nitrogen determination system (Nidesy) for measurements in molten iron is developed. The method is based on the exchange of nitrogen from the molten iron to a gas phase, the transformation of this gaseous nitrogen in nitrogen oxides and the measurement of produced NO₂ by a suitable sensor. The measurement apparatus consists of three mains parts: first, an apparatus that puts the liquid and gaseous phase in contact and conveys the gas bubbled from the bath to a reactor: blower probe; second, a reactor that transforms N₂ of the blown gas into NO₂: reactor; third, an electrochemical sensor for NO₂ determination: NO₂ sensor. The laboratory experimental activity consists of a step of optimisation of the engineering and operative aspects of whole apparatus; as a result, an instrumental configuration with high sensitivity allowing high accuracy and precision has been obtained, as well as creation and use of the calibration curve (ΔEMF vs dissolved N) for measuring in liquid iron at 1650°C. On the basis of the obtained results a Nidesy for both laboratory and industrial use can be envisaged, for example in a kinetic study of nitrogen absorption/desorption, or in a steel plant, such as a tundish or a continuous casting mould