Refractories for Basic Oxygen Furnace Aug28

Refractories for Basic Oxygen Furnace...

Refractories for Basic Oxygen Furnace  The main objective in the development of refractories for basic oxygen furnace (BOF) is to get a useful lining life of the wear lining so as to obtain maximum availability of the BOF. Longer lining life not only results in lower refractories cost but it also enables higher productivity through increased furnace availability. The following are the basic requirements from the refractories of BOF. Thermal spalling resistance Corrosion resistance Abrasion resistance Oxidation resistance Hot modulus of rupture BOF is lined normally with a permanent lining and above it there is a wear lining. Permanent lining thickness may vary from 100 mm to 120 mm and is made of chrome-magnesite permanent lining which is given on the full height of the BOF. The refractories available for use in wear linings of BOF range from tar or pitch bonded dolomite or magnesia (MgO), chrome magnesite, or magnesium chrome refractories to the advanced refractories that are made with resin bonds, metallics, graphites, and sintered and/or fused magnesia that can be with a purity of 99 %. Bricks are designed with a combination of critical physical properties to withstand the high temperatures and rapidly changing conditions/environment throughout the BOF heat cycle. A balance of different properties such as hot strength, oxidation resistance, and slag resistance is necessary from the BOF refractories for good performance. When BOF process of steelmaking was introduced in 1950s, converters were lined with tar dolomite bricks and stabilized burnt dolomite bricks. These refractories were then replaced by semi stabilized burnt dolomite bricks and tar bonded and fired bricks made of synthetic magnesia dolomite clinker. Chrome magnesite, or magnesium chrome refractories were used for lining of some BOFs.  High purity burnt magnesia bricks were also used in some of BOF...