24451. Carborundum used for making crucibles for melting non-ferrous metals is chemically
24452. Which of the following impurities reduces the refractoriness of magnesite bricks ?
24453. Crushing strength of a refractory
24454. Ramming masses are used for
24455. Bottom of basic open hearth furnace are constructed of
24456. Which form of silica has the highest specific gravity ?
24457. Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of
24458. __________ is the measure of the strength of refractory under the combined effect of temperature & load.
24459. National Statistical Day is observed on
24460. The Vernacular Press Act of 1878 was introduced by
24461. Lower wall courses of soaking pits are made of __________ bricks to avoid the action of molten slag & scale.
24462. Addition of grog in fireclay brick during its manufacture is advantageous, because it results in
24463. Slide gates in teeming laddie used for steel pouring in ingot moulds is lined with __________ bricks.
24464. Fireclay refractories
24465. Addition of zircon to silica refractory brick improves its
24466. Which is a neutral refractory ?
24467. Permeability of bricks is a measure of the
24468. With increase in the density of silica refractories, its
24469. Magnesite chrome refractories
24470. Fireclay bricks is not used for lining the
24471. Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as __________ percent.
24472. Refractoriness under loads (RUL) is quite close to the fusion temperature (PCE) for __________ bricks.
24473. Refractories subjected to alternate cycles of heating & cooling are liable to loose their resistance to
24474. Thermal spalling mainly occurs during __________ of furnaces.
24475. An ideal refractory should have high
24476. Ganister is a source of the
24477. Which brick undergoes maximum shrinkage on drying ?
24478. Which is the stable form of silica upto 1470°C ?
24479. Hot face insulating linings of high purity alumina fused mullite are used, where
24480. Semi-silica bricks compared to silica bricks have
24481. Mixing of ground refractory material and water is done in a __________ mill.
24482. Maximum apparent porosity of magnesite bricks is about __________ percent.
24483. Dilatometer is used for the determination of __________ of refractories.
24484. With decrease in porosity, the __________ of the refractories decreases.
24485. Porosity of silica bricks varies from __________ percent.
24486. Colour of fireclay bricks is
24487. Rate of slag attack on refractories increases with rise in temperature due to the
24488. Which of the following is not a high alumina refractory material ?
24489. Magnesite chrome bricks are used in the
24490. Mullite is chemically represented by
24491. __________ bricks are used in the burning zone of a cement rotary kiln.
24492. Furnace atmosphere for softening temperature determination of refractories (in which segar cones are placed) should be
24493. Roof of a basic open hearth furnace is lined with __________ bricks.
24494. High alumina refractories are used in the
24495. Maximum shrinkage in volume occurring during burning/firing of dried refractories may be as high as __________ percent.
24496. Porosity of fireclay refractories is __________ percent.
24497. SiO2 percentage in firebrick is about
24498. Porosity is induced in insulating refractories by adding
24499. Magnesite bricks have poor resistance to attack by __________ slag.