Plaster of pans

Slip casting is common in the ceramics industry. The material to be cast is milled to a mean particle size of a few microns. A slip is made by mixing the finely divided material with a liquid suspending medium. The slip is then poured into a suitable mold (e.g., of plaster of pans). The liquid in the slip is drawn into the mold by capillary forces and the solids are deposited in a coherent form. For TiBj, ZrBj and CrBj a suspending medium of 5-7 wt% cyclopentadiene in xylene is recommended. A 3 wt% aqueous solution of carboxymethylcellulose is the best dispersing medium... 

The main physical and technological research work was done with an industrial plaster of pans. Synthetic hemihydrate prepared from dihydrate (MERCK 2161) and autoclaved a-hemihydrate were used for the examination of die retardation mechanism. 

Calcium sulfate is also used in a variety of commercial applications. The dihydrate, mined as gypsum, is used in Portland cement and for gypsum wallboard. When the dihydrate is heated, it yields the fine hemihydrate powder, CaS04 5H2O, known is plaster of paris. When plaster of pans is mixed with water, it makes a paste, or slurry, that hardens to form accurate molds. These reactions are summarized in Equation (13.28) ... 

Callletet and Mathlae law phys chem The law that describes the relationship between the mean density of a liquid and its saturated vapor at that temperature as being a linear function of the temperature. lu-a ta an mo thT-os, 16 ) cajeputol See eucalyptol. ka -3-p3,t6l calabarine See physostigmine. k3 lab-3,ren calcined gypsum See plaster of pans. kal,sTnd jip som calcined soda See soda ash. kal,sTnd so-da ... 

In the commercial production of plaster of Paris by the Kettle Process, the gypsum is first ground and then transferred to shallow pans, known as kettles, each holding some 12 tonnes of gypsum. During calcination, the loss of water may go beyond the first stage shown in the equation above, resulting in the loss of a further 1 Yi molecules -... 

Drying Rooms For drydng materials that cannot be agitated, the drying room, and tray drier (which there are many varieties) can be used. In the former, the material may be spread on pans and these stacked in a rack, which leaves a space between the trays for air circulation. The room has loosely fitted side walls of plaster board, or similar material, or even canvas, and contains a steam radiator. The natural circulation of the warm air removes the moisture the drying period is generally long, for example, one or two days. 

The inorganic classification includes the metal pan type, consisting of a perforated metal pan with a sound-absorptive mineral wool pad the perforated cement-asbestos type, consiting of a perforated cement-asbestos sheet with a sound-absorptive mineral wool pad acoustical plasters and tile prepared from mixtures of inorganic or mineralized fibers with or without asbestos and other fillers. In general, acoustical products in this classification possess good fire and flame resistance, but are relatively expensive and difficult to manufacture and apply. 

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