Bricks, manufacture from

In the class of basic refractories are included bricks manufactured from chrome ore [(MgFe)(AlCr)204], periclase (MgO), calcined dolomite (CaO, MgO), olivine [(MgFe)2SiOJ, and mixtures of these materials. 

Boric oxide is also a very undesirable impurity. Researchers in the 1960s and 1970s found that one of the major reasons for the excellent hot strength of dead-burned Grecian magnesite, which had such a dramatic effect on the increased life of pitch-impregnated, burned MgO brick manufactured from this material and used in the impact pads of basic oxygen furnaces in the... 

Silica bricks are manufactured from crushed ganister rock containing about 97 to 98 percent silica. A bond consisting of 2 percent lime is used, and the bricks are fired in periodic kilns at temperatures of 1,500 to 1,540°C (2,700 to 2,800°F) for several days until a stable volume is obtained. They are especially valuable when good strength is required at high temperatures. Superduty silica bricks are finding some use in the steel industry. They have a lowered alumina content and often a lowered porosity. 

Tiles may be classed under throe divisions, paving tiles, roofing tiles, and drain tiles, each of which comprehend numerous other varieties. The great distinction betwoen tiles and bricks arises from the greater thinness of the former, and the consequent necessity of increased purity and tenacity in the mass greater care is also bestowed upon tho processes of their manufacture, tiles being always dried undsr cover. 

Plenty of radiant heat is liberated, but only to the refractory brick walls. The bricks then reradiate the heat back into the gaseous products of reaction. This is called adiabatic combustion because no heat is lost from the combustion reaction to radiation. The adiabatic-combustion temperature for the preceding reaction [Eq. (21.1)1 is about 2300°F. The refractory used to contain this high temperature is manufactured from 90 percent alumina. Such refractory may be exposed to temperatures of up to 2900°F, without damage. 

Clay fuses at from 2800 tit 3200T. tl53fi to 1760 0 the uppet limit being for flint clay and the lower for the plastic form which, due to its cc-mcming qualities, is especially valuable in fire-brick manufacture, Red brick is not suitable for refractory service, nor is insulating brick. There are several fire-clay furnace cements on the market that arc adaptable to monolithic lining. The standard sire of fire-brick and insulating brick is 9 inches by 4i inches by 2i inches 122.9 by 11.4 by 6.4 centimeters). 

Bricks are manufactured from deaerated shale and are very dense with low absorption. ASTM C-279 Type H or L. 

Large quantities of refractory materials are required for the construction of melting furnaces. The suifaces of the tank furnaces in contact with the glass melt are lined with melt cast or isostatically pressed bricks (e.g. of zirconia) and the cover over the glass tanks is manufactured from mullite or silica materials. 

Large-quantities of quicklime are used in the manufacture of sand-lime bricks and aerated concrete blocks. These are construction materials which are manufactured from lime-containing and silicate-containing raw materials and whose strength is due to the hydrothermal reaction of the raw materials to calcium silicates. 

Pure chromium oxide bricks with 95% Cr203 are manufactured from synthetic Cr203 and are utilized in the refractory linings of tank furnaces for the production of E-glass fibers. 

Figure 4.1 shows coimection between a wooden jamb (12) assembly and plastic brick (14) manufactured from composite. Figure 4.2 shows the structure of plastic brick (14) which is composed of cellular PVC core (21), SAN stabilizing layer (22), and non-cellular PVC wear layer (23). This combination was found to be very resilient and scratch-resistant. 

Bwichgwyn Quartzite. A quartzite from Bwlchgwyn, N. Wales, used as a raw material for silica-brick manufacture. Chemical analyses are ... 

DTA and dilatometric curves for a clay containing about 20% dolomite and used in the manufacture of facing brick are shown in Fig. 12.Above 700°C, the clay begins to shrink following the completion of dehydroxylation and commencement of dolomite dissociation. The residue from the dolomite reacts with the alumina and silica from the clay resulting in a large expansion at about 850-1000°C. It is a requirement that bricks made from this clay must be heated slowly to prevent cracking. 

Thermal dilatometric curves obtained for six bricks extruded from different raw materials are shown in Fig. Curves for those manufactured from similar raw materials, but made by different forming methods, i.e., soft mud, dry press, and stiff extrusion, are shown in Fig. 23. From room temperature up to 500°C, the dimensional change is approximately linear and is due to thermal expansion. The abrupt increase in expansion (500-800°C) is due to phenomena such as quartz inversion, exfoliation of the illitic, and chloritic minerals due to dehydroxylation, and, possibly, the escape of CO2 under pressure. 

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