Study On Sensing Method For Determination Of Manganese Activity In Iron Melts

Manganese is one of the important elements in steel, it can improve the intensity and hardenability of steel, change the morphology and distribution of sulfide, prevent hot shortness and improve the hot-working character. Different steels need different manganese content. In order to produce steel with high quality, the manganese content need be strictly controlled during the refining process. Now the content of manganese in steel are almost measured by sampling analysis, there are many problems with this method such as a long measuring time, delayed information, so it cannot satisfy the the demand of modern iron and steel production. So, this study adopted Sensing Method to determinate the manganese activity in industrial iron melts, to settle theoretical and experimental basis for industrial application of manganese sensor.In this work, solid electrolyte was prepared by solid-phase synthesis method. MnO was used as auxiliary electrode material and PVA as bonder to prepare auxiliary electrode on the surface of solid electrolyte tube. Two kinds of manganese sensors with different structures were made with the mixed power of Cr and Cr2O3as reference material and Mo wire and Mo-ZrO2metal ceramic as the electrode lead, the type of cell can be expressed as Mo|Cr, Cr2O3|ZrO2(MgO)|MnO|[Mn]Fe|Mo-ZrO2The sensors were used to determine the activity of manganese in liquid iron melts with different manganese content in1600℃. The research results are obtained as follows:(1)(Zr02)o.92(MgO)0.08solid electrolyte was prepared by hot injection molding technology and once sintering solid-phase synthesis method. And the solid electrolyte has dense structure, good gas-tight, and well-distributed composition. The solid electrolyte can be used to made manganese sensor.(2) MnO auxiliary electrode were prepared on the surface of (Zr02)o.92(MgO)0.08solid electrolyte tube by coat-sintering method. The auxiliary electrode were well-bonded with solid electrolyte and there was a about150μm MnO penetration in the surface of solid electrolyte tube. In conclusion, the auxiliary electrode satisfied the demand of manganese sensor, and coat-sintering method can be used to prepare MnO auxiliary electrode.(3) In this study, Two kinds of manganese sensors with different structures were prepared. The result of thermal shock performance experiment showed the manganese sensor had good thermal shock performance and can be used in the liquid iron at1600℃.(4) The prepared manganese sensors were used to determine the activity of manganese in liquid iron melts with different manganese content in1600℃. The results indicated that the response time of the manganese sensor Ⅰ was about3s, and the stable EMF could last about7s, the response time of the manganese sensor Ⅱ was about10s, and the stable EMF could last about10s, and the accuracy of measurements is±1mV.