Studies on decarburization of MgO-c refractories during ladle preheating

• The effect of ladle pre-heating conditions on the wear of MgO-C refractories at different steel plants has been investigated. The focus has been on refractories used in the slag zone, some including which contain anti-oxidants. This investigation shows that the wear /corrosion of the slagline refractories initiates already at the ladle pre-heating during real industrial conditions. The degree of the decarburization process is dependent both on the refractory composition, time and the pre-heating fuel or environment. For refractories without anti-oxidants, the refractory decarburization is 3.8 times slower when coal gas is used in ladle pre-heating than when a mixture of oil and air is used. Ladle pre-heating of the refractories without anti-oxidants leads to direct wear of the slagline refractories due to total loss of matrix strength, resulting in a sand-like product independent of the pre-heating method. When the refractories containing antioxidants are compared to each other, the decarburization rate was lower when coal gas was used in ladle perheating than when the refractories are pre-heated by electrical means. The cracking tendency of the refractories is enhanced by the increasing size of anti-oxidants. The refractory containing coarser grains of anti-oxidants (<3000 μm) cracked much early than those containing finer grains (<100 μm). For example after 6 weeks in storage, the crack thickness was 1.5 mm for  large-grained refractory whereas 0.3 mm for the fine-grained refractory.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

refractories

reduction-oxidation (redox) corrosion

anti-oxidants

pre-heating

decarburization

decarburization rate

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