Influence of Zn Addition on Properties of Metal Composite Low Carbon MgO‐C Refractories

Abstract

Influence of Zn addition (0, 0.5, 1, 1.5, 2, wt%) on hot modulus of rupture(HMOR), thermal shock resistance, oxidation resistance and slag corrosion resistance of low carbon MgO-C refractories have been investigated. The results show that with the addition of Zn (I) the HMOR of the specimens noticeably increase, with addition of Zn is 1.5% and 2% ,it is twice as much of contrast specimen without Zn addition (from 13.24 MPa to 26.27 MPa); (II) strength after thermal shock is higher than contrast specimen, with addition of Zn rise more than 1%, residual strength ratio increase to above 92% and implied good thermal shock resistance; ( ) III oxidation thickness of specimens decrease obviously both at 1000 and 1500 °C °C, and with addition of Zn is more than 1%, oxidation resistance of specimens was significantly improved;(IV) slag corrosion resistance of crucible specimens after slag corrosion (1600 × °C 3h) has improved with addition of Zn is more than 1%, and the results implied that there is relationship between slag corrosion resistance and Zn addition as well as oxidation resistance. INTRODUCTION With clean steel production increased year by year, low carbon MgO-C refractories become the new hot spot, especially in developing metal incorporated low carbon MgO-C refractories for applications in metallurgical industry. For example, Al/Si bearing low carbon MgO-C bricks have been successfully used in steel ladles with satisfactory service performance. But influence of Zinc to in-situ reaction and performance of non-burned MgO-C refractories have not been reported. Accordingly, Influence of addition of Zn on properties (hot modulus of rupture, thermal shock resistance, oxidation resistance and slag corrosion resistance) of metal composite low carbon MgO-C refractories were reported in this paper. Six specimens have been prepared by using fused magnesia (MgO > 97 %) and flake graphite as starting materials, and phenolic resin as binder, pressing under 180 MPa and heating at 200°C. They are: (I)Specimen C12 (straight low carbon MgO-C, 12% flake graphite, 2% Al as antioxidant);(II)Specimen A4.5 (low carbon MgO-C , 2% flake graphite, with addition of 4.5% Al); (III)Specimen A4.5Z0.5, A4.5Z1, A4.5Z1.5, A4.5Z2 (low carbon MgO-C, 2% flake graphite, 4.5% Al, with addition of Zn 0.5%, 1%, 1.5% and 2% respectively). These specimens have been tested for ( ) I hot modulus of rupture (HMOR) at elevated temperatures up to 1400°C, ( ) II thermal shock resistance(TSR) at temperature differences ( T) from 25°C to 1100°C by standard testing methods under embedded carbon condition, ( ) III oxidation resistance at temperature 1000°C and 1500°C for 3h, (IV) slag corrosion resistance by static crucible method (1600 × °C 3h) in reducing atmosphere