Brick refractory

INSULATING BRICKS REFRACTORY BRICKS REFRACTORY BRICKS 

ADDITIONAL quantity OF CATALYST CAN BE LOADED IN THE CONVERTORWITHOUT INCREASING HEIGHT 

Case study Addition of some more catalyst to the converter of a sulphuric acid plant was done (without increasing the pressure drop) by removing one layer of brick-hning which was provided in the beginning itself. Please see Fig. 3.1. 

A cooling water pump is mnning at about 30 % of its rated capacity at present when the plant is producing 80 tonnes per day. In future, when the plant capacity is to be increased to 120 tonnes per day, the pump will have to be run at about 45-50 % of its rated capacity. This is well within its capacity, and it can be easily run without any change. 

However, if the cooling water pumps is already running at 65-70 % of its capacity (when the plant is producing 80 tonnes per day), it will have to be run at more than 95 % of the rated capacity and this may not be possible. Replacement by a bigger capacity pump will be required in such a case. 

In The Netherlands refractory bricks are manufactured by a firm called Gouda Vuurvast Ltd. and some of its customers are  

This list is far from complete. The glass industry, ceramic industry, manufacturers of fire places, etc., could also be added to it. 

Each branch of industry is characterized by specific (production) processes with their corresponding requirements for refractory products. 

In the case of refuse incinerators a distinction must be made between the combustion of household and the incineration of chemical waste. Burning household waste involves steam generators used to generate electricity. The combustion chamber is provided with steam pipes which have to be protected against corrosive gases by means of SiC-containing materials. 

In addition the walls of the combustion chamber must also be shielded from corrosive slag. Chemical waste is mostly incinerated in a rotating tubular oven coated with chromium-containing corundum stone or phosphate-bound corundum stone. 

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Alundum is used for highly refractory bricks (m.p. 2000-2100 C), crucibles, ref ractory cement and muffles also for small laboratory apparatus used at high temperatures (combustion tubes, pyrometer tubes, etc.). 

The roof, in the form of a dome, is either comprised of refractory brick held in place by a water-cooled steel roof ring, or it may be composed of water-cooled panels. Sometimes water-cooled rings or glands are placed on the roof around the electrodes to maintain the refractory. On high power furnaces refractory is used around the electrodes to minimize the possibiUty of electrical short circuits. 

Dead-burned dolomite is a specially sintered or double-burned form of dolomitic quicklime which is further stabilized by the addition of iron oxides. Historically, it was used as a refractory for lining steel furnaces, particularly open hearths, but as of this writing is used primarily in making dolomite refractory brick (see Refractories). 

Table 5. Physical Properties of Alumina, Silica, and Zirconia Refractory Brick ...

Table 8. Mean Specific Heats of Refractory Brick and Minerals, Between 0°C and the Indicated Temperature, J/(kg-K) ...

Another measure of refractoriaess is the hot-compressive strength or hot-load test for refractory bricks or formed specialties. The specimen carries a static load from 69 kPa (10 psi) to 172 kPa (25 psi). It is heated at a specific rate to a specific temperature which is then held for 1.5 h, or it is heated at a specific rate until it fads. The percent deformation or the temperature of fadure is measured. The procedure is described ia ASTM C16. 

Anhydrous Borax. Anhydrous borax is produced from its hydrated forms, borax decahydrate or pentahydrate, by fusion (Pig. 6). Low temperature calcining is usually an intermediate step to remove water of hydration. This material is fed to a refractory brick-lined furnace and fused to a mobile Hquid at about 1000°C. 

A calcining kiln is a horizontal steel cylinder, slightly sloped to help the coke move forward and lined with refractory brick. The raw coke is fed at the upper end, natural gas or oil is burned at the lower end, and the combustion gas flows through the kiln above and against the coke stream. 

During much of the nineteenth century, the United States was the principal world producer of chromite ore (37). However in the latter twentieth century the United States has become completely dependent on imports from South Africa and Turkey (chromite) South Africa, Zimbabwe, Turkey, and Yugoslavia (ferrochromium) and the Philippines (chromite for refractory brick). 

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... 

Direct rotary kiln. This is a metal cyhnder lined on the interior with insulating block and/or refractory brick. It is suitable for high-temperature operations. 

A crystalline form of free silica, extremely hard and inert chemically very resistant to heat. Quartz in refractory bricks and amorphous silica in diatomaceous earth are altered to cristobalite when exposed to high temperatures (calcined). Cristobalite is extensively used in precision casting by the hot wax process, dental laboratory work, and certain speciality ceramics. 

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