Sand-line bricks

Car-bottom furnaces differ from standard types in that the charge is placed upon movable cars for running into the furnace enclosure. The top oi the car is refractory-lined and forms the furnace hearth. The top only is exposed to heat, the lower metal structure being pro-tec ted by the hearth brick, sand, and water seals at the sides and ends and by the circulation of cooling air around the car structure below the hearth. For use where floor space is hmited elevator furnaces serve similar purposes. 

The rotary-hearth furnace consists of a heating chamber lined with refractory brick within which is an annular-shaped refractory-lined rotating hearth. Around the periphery of the rotating hearth, sand or circulating hquid seals are employed to prevent air infiltration. It can be made semicontinuous in operation. The hearth speed can be... 

Fluidized-bed chlorination was started in 1950. The titanium raw material (with a particle size similar to that of sand) and petroleum coke (with a mean particle size ca. five times that of the Ti02) are reacted with chlorine and oxygen in a brick-lined fluidized-bed reactor (Fig. 16, c) at 800-1200 °C. The raw materials must be as dry as possible to avoid HC1 formation. Since the only losses are those due to dust entrainment the chlorine is 98-100% reacted, and the titanium in the raw material... 

Illmenite sand with steam and hydrochloric acid was handled in the spherical digesters. The temperature in the digesting process was ambient to more than 130°C. Therefore brick lining was applied on a butyl rubber lining 5 mm thick with hardness of 55°A. The rubber serves as a cushioning medium beneath the brick lining, as well as resisting the temperature at the brick rubber interface of about 100°C. 

Reverberatory furnaces3 are particularly suitable for fines and flue-dust from the blast-furnaces. Their walls and roof are lined with silica bricks, and the hearth with silica sand. A typical charge consists of2 ... 

Anhydrous alkali silicates with Si02/alkali oxide > 1.5 (solid glasses) are manufactured by reacting fine particulate quartz sand, which is as pure as possible, is clay-free and has a low iron content, with alkali carbonates or hydroxides at 1300 to 1500°C in tank furnaces lined with refractory bricks or in rotary tube... 

Refractory bricks (7%). It is useful in refractory linings for furnaces and the kilns of the cement industry and in moulding sands in foundries because of its high melting point and relatively low cost. 

String. A fault in glass with the appearance of a straight or curled line the usual cause is slow solution of a large sand grain or other coarse material. String Course. A distinctive, usually projecting, course in a brick wall its purpose is aesthetic. 

Today, sand bricks are used for lining furnaces such as L-D converters. These have properties similar to semi-silica bricks and are cheaper and quicker to install than normal bricks. They last as long as regular bricks and tiieir thermal conductivity are low. This reduces the heat loss from the furnace. Small induction melting furnaces with up to a three-ton capacity are lined with pure silica sand, which is rammed against a steel former. Afterward, induction heating fires it. 

The earliest refractories used in furnaces were natural stones quarried into bricklike shapes and natural clays and sands used as rammed lining components. Bricklike shapes were used because of the thousands of years of practice using stone and clay masonry in buildings. Thus, it was natural that brick furnace linings would become larger than simple enclosures. 

Rehneries generate signihcant quantities of waste materials that are most easily disposed of by incineration. Figure 14 shows a typical fluidized bed incinerator using sand as the bed material. The interior is lined with superduty hre brick and operates around 1000°C (1832°F). Thermal cycling and mild abrasion are the... 

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