Gypsum, "stucco

GUMA or GUMI — Olitet Sulphur and Coagulum. It is a Ferment, and may be dissolved by milk. GUMA CUPRI — Verdigris, or Vitriol. Also called Gypsum, Stucco, Plaster of Paris. 

KEY WORDS gypsum, stucco, disintegration, water demand, consistency... 

Modem gypsum board production is a complex process that involves the preparation of an aqueous slurry by mixing calcined gypsum (stucco) with water... 

Any of these mortars can be used for unit masonry or for stucco (exterior plaster). The finish coat in conventional interior plastering is composed of either neat time putty or a sanded putty, gauged with Keene s cement or gypsum-gauging plaster. The former is called a whitecoat finish the latter a sandfloat finish. 

P-Hemihydrate. The dehydration of gypsum, commonly referred to as calcination in the gypsum industry, is used to prepare hemihydrate, or anhydrite. Hemihydrate is generally called stucco in North America and plaster in many other continents. In North America, plaster is differentiated from hemihydrate or stucco by the inclusion of additives to control intended use properties, eg, rehydration time, density, coverage, strength, and viscosity. 

Calcined Anhydrite. Soluble anhydrite, or second-settle stucco, has physical properties similar to those of gypsum plaster. It hydrates to the dihydrate rapidly in water. Its outstanding property is its extreme affinity for any moisture, which makes it a very efficient drying agent (see Desiccants). In ambient moisture-laden air, it readily hydrates to hemihydrate. Soluble anhydrite, under the trade name Drierite, is widely used as a desiccant in the laboratory and in iadustry. A small amount is also used as an insecticide carrier. Small amounts of soluble anhydrite are unintentionally produced in most commercial calciners during hemihydrate production. 

Gypsum, raw 25 total 5 Imp-mill type grind and calcine to stucco... 

Gypsvun, lie says, should not he used in stucco, because it sets too rapidly and thus interferes with even drying. Vitruvius, like Theophrastus, uses the word gypsum not in the sense of the native mineral, but rather to indicate what we call the plaster of paris which is produced by its burning. ... 

Staff Portland Cement Plaster Stucco Manual, Portland Cement Association. Skokie, 1L. I99(i. hitpif/www.portccmcnl.org/index.usp Staff Anuiutl Book of ASTM Standards. 1997 Cement Lime Gypsum. American Society for Testing and Materials. West Conshnhocken. PA. 1997. http //www.ust nt.org/... 

Construction Materials In tape joint compounds in gypsum spray plaster in ceramic tile adhesives, grouts, and mortars in cement mortars, stuccos, and plasters in concrete as wallpaper adhesive as a ceramic processing aid as a thickener for latex paint... 

When mounted in Cargille liquid, 1.528 RI gypsum has a blue outline with central screening on the dispersion screening device. This is a good method for finding small amounts of raw gypsum in stucco. 

ABSTRACT In gypsum board xoduction. the amount of water required for a stucco slurry with a suitable fluidity is considerably greater than the amount necessary for hydration of the stucco. Since excess water must be removed by drying, it is advantageous, from an energy point of view, to reduce the consistency or water demand of stucco. Constant board density is maintained thereby through increased addition of foam. 

A relatively pure form of natural gypsum (Terra Alba) consisting of 98.6% CaSO ZHjO was used for this study. The gypsum was ground to pass a 150-p.m (No. 100) sieve and calcined in a laboratory kettle designed for both continuous and batch operation. In this manner, three 15-kg lots of stucco were prepared by continuous calcination, and three 5-kg lots of stucco were calcined by the batch process. To two lots of the latter, either calcium chloride or surfactants were added. 

After calcination, the stuccos were cooled to room temperature with constant stirring to remove all entrained water vapor. The residual gypsum content and soluble anhydrite content as determined by phase analysis 9] were always less than 4.0 and 2.0%, respectively. 

This type of measurement is widely used in Europe [West German Industrial Standard (DIN) Test Methods for Gypsum Plaster (DIN 1168)] to determine the so-called water stucco factor, that is, the amount of stucco in grams that can be wetted by 100 mL water. The method consists of sprinkling stucco into the water at a specific rate without mechanical mixing. Therefore, it differs from other consistency measurements in that only spontaneous disintegration occurs. Pouring Consistency... 

In considering other factors that may influence water demand, many intrinsic stucco properties must be taken into account such as purity, particle size and morphology of the gypsum, calcination methods, and stucco surface properties. In addition, the water demand of stucco is dependent on its history such as aging time and conditions, aridization, and presence of surface active agents. 

Marasperse. [Borregaard LignoTech] Lignosulfonates or oxylignins dispersant emulsion stabilizer for ceramic slurries, stucco, agrk. formulations, dyestuffs, gypsum board, industrial cleaners, cement slurries, paper m., in mfg. of brick, tile, refractmies. 

OTHER COMIVIENTS used for creating casts and moldings used in tiles, stucco, wall plaster, and wallboard present in dental casting materials can be formed by heating gypsum. 

The plaster found wide application in ancient Egypt [2], It was applied as mortar and to stucco decoration, for example in Tutankhamen s tomb, for firnshing the tombstones of calcite (called alabaster). As mortar it was used in pyramids, in Giza. The beginning of its application is not establish it is regarded that it falls in the period from 5,000 to 3,400 year before Christ [2], The plaster application, instead of lime Jaworski explains by the lack of fuel, because the limestone are more easily accessible than gypsum raw materials [2]. 

Uses Wall plasters, gypsum wallboard, tiles, stucco, blocks, and moldings for building industry statues jewelry castings paper industry pharmaceuticals (plaster of Paris bandages, orthopedic and dental casts) Regulatory FDA approved for orals JP compliance... 

Mortar m6r-tor [ME morter, fr. OF mortier, fr. L mortarium] (14c) n. (1) Material used in a plastic state which can be troweled, and becomes hard in place, to bond units of masonry structures Note — The word mortar is used without regard to the composition of the material, and is defined only with reference to its use as a bonding material as contrasted with the words stucco and plaster ). (2) A mixture of gypsum plaster with aggregate or hydrated lime, or both, and water is to produce a trowelable fluidity. 

Stucco st9-(i)ko [It, of Gr origin akin to OHGr stucki piece, crust, OE stocc stock] (1598) n. (1) An exterior finish, usually textured composed of Portland cement, lime, and sand, which are mixed with water. (2) A fine plaster used for decorative work or moldings. (3) Simulated stucco containing other materials, such as epoxy as a binder. (4) A partially or fully Calcined gypsum that has not yet been processed into a finished product. 

The use of gypsum, or plaster of Paris as it is caUed, for different objects - figurines, bowls, stucco work and so on - has been described in the historical section. In our time the most important - and very large - application is for producing gypsum wall-board (drywall), which has almost replaced other waU coverings in buildings. 

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