New Bharat Refractories Ltd. Kolkata, West Bengal

Advantages ::   Tundish Refractories Tundish linings generally include a back-up safety lining and wear (service lining. The wear lining has commonly been burnt alumina bricks but in recent year there has been increasing use of low cement high alumina castable. Flow Control Flow control Refractories include two systems viz a sliding nozzle or sliding gate system and a stopper system. These systems are used to regulate the flow of molten steel from ladle to tundish and from tundish to mould respectively. Pouring refractories There are two types of pouring refractories viz. the long shround nozzle (ladle shroud) for pouring molten steel from ladle to tundish, and the submerged entry nozzle (immersion nozzle) from the tundish to mould. Both of these applications require corrosion and thermal shock resistance. In the early years of continuous casting, fused silica material was used but at present alumina graphite is the typical material for submerged nozzle. In the submerged entry nozzle there is an internal fitted nozzle with slits for argon gas bubbling as a way of preventing alumina inclusion in molten steel from causing build-up and nozzle clogging. On the exterior of the submerged entry nozzle at the slag line an insert of zirconia-graphite is included in the alumina-graphite body, to provide added corrosion resistance. Application ::   In various regions of furnace based on Continuous Casting

Aluminum has gained a lot of importance in the field of metals in the recent past. India blessed with a huge reserve of bauxite, the basic raw materials for the production of aluminum, has rightly focused her attention on the development of aluminum industry in the country.

• Bulk density,g/cm3 2.89 2.89 3.02
• Cold crushing strength, MPa52 30 47
• Modulus of rupture at room tem. MP12 10

• Thermal shock resistance(900) time20 25
• Abrasive index(ASWTC-704)9 8

Solubility resistance to hot metal Penetration prevention of molten substances such as hot metal, etc. Superior thermal stress resistance High thermal conductivity Good spalling resistance. Keeping the above in view, new carbon blocks have been developed for improved characteristics such as: Prevention of matrix solution by adding alumina and by adding silicon Improvement of pore size distribution by improved forming method Improvement of deformability and thermal conductivity by using a lot of natural graphite.

Consequently, both chemical and thermo-mechanical conditions are very severe here. The primary criteria for Refractories to be used in these zones are that they should have higher tendency to form a stable coating of clinker which enhance the life of the refractory by protecting it against the mechanical abrasion and chemical action of the clinker. The usage of high alumina Refractories in this zone is diminishing with the advent of large diameter rotary kilns with pre-heaters and pre-calcinators due to increased thermal as well as mechanical load.