What are the different types of gypsum products?
Abstract
- Background. Three types of gypsum products were commonly used in dentistry to fabricate dental casts and dies which includes dental plaster, dental stone, and improved stone.
- Methods. The control group was prepared by mixing dental plaster with water. ...
- Results. ...
- Conclusion. ...
How many types of gypsum are there?
Which gypsum product is the oldest and weakest?
- A calcium sulphate hemihydrate (CaSO 4, 0.5H 2 O)
- Oldest form of gypsum.
- Weakest of all gypsum products.
- When mixed with water, it rehardens to a dehydrate.
What things are made out of gypsum?
- 900 pounds of lead
- 700 pounds of zinc
- 1,300 pounds of copper
- 3,600 pounds of bauxite (aluminum)
- 30,000 pounds of ore
What are products made of gypsum?
- Drywall partitions using metal frames.
- Suspended ceilings using metal frames Furring and wall linings.
- Prefabricated building units.
- Drylining blockwork/concrete walls using dot and dab of a gypsum-based bonding compound.
What are the four types of gypsum?
GypsumMajor varietiesSatin sparPearly, fibrous massesSeleniteTransparent and bladed crystalsAlabasterFine-grained, slightly colored30 more rows
What are 5 gypsum types?
The major types of Gypsum products that are available are, Type I — Impression Plaster. Type II — Dental Plaster. Type III — Dental Stone Type IV — Improved Dental Stone or Die stone or High Strength Stone. Type V — Dental Stone, High Strength, High Expansion.Aug 20, 2017
How many types of gypsum boards are there?
The different types of gypsum board generally available in the market are clued wallboard, backing board, core board, fire-resistant gypsum board, water-resistant gypsum board, and gypsum form board.
What are the three forms of gypsum?
three forms of gypsum products are typically used pouring up study models::::: Model plater, Dental stone and High strength stone. All three of these forms consist of HEMIHYDRATE crystals. The only differences between the three are seen in sizes shape and porosity of hemihydrate crystals .
What is a type of gypsum?
Gypsum rock is mined or quarried, crushed, or ground into a fine powder. The calcined gypsum becomes the base for gypsum plaster, gypsum boards, and other gypsum products. Another type of gypsum is synthetic gypsum. One example of synthetic gypsum is FGD gypsum.Apr 30, 2021
What is gypsum Class 10?
Gypsum is a common mineral. Its chemical name is calcium sulfate dihydrate (CaSO4. 2H2O). It is found millions of years ago in saltwater underwater layers. When the water evaporated it released the minerals.May 1, 2021
What is this gypsum?
Gypsum is composed of calcium sulphate (CaSO4) and water (H2O). Its chemical name is calcium sulphate dihydrate (CaSO4. 2H2O). Gypsum can be milled mixed with water and then resume its original rock-like state.
What are the sizes of gypsum board?
The standard size gypsum boards are 48 in. wide and 8, 10, 12, or 14 ft. long.
What are the different types of Sheetrock?
6 Common types of drywallRegular drywall. Regular drywall, often called white board, is the most common type used in ceilings and walls in homes and commercial projects. ... Mold-resistant drywall. ... Plasterboard. ... Soundproof drywall. ... Fire-resistant drywall. ... VOC-absorbing drywall.Oct 15, 2021
What is Type 3 gypsum used for?
Gypsum (calcium sulphate dihydrate) is a naturally occurring mineral used in dentistry to fabricate models (Figure 12.1a), casts and dies (Figure 12.1b)....DEFINITION.Type IEdentulous impressions and mounting casts on articulatorsType IIPlaster (model)Type IIIDental stone, die, model2 more rows•Jan 1, 2015
What is another name for gypsum?
n. Calcium Sulphate, calcium sulfate, mineral.
What is the strongest gypsum product?
High-strength stone is the strongest and most expensive of the three gypsum products, and it is used mainly for making casts or dies for crown, bridge, and inlay fabrication.Feb 11, 2020
What are the colors of gypsum?
In mass and homogeneous samples, gypsum is found in carmine, red, brown, yellow and gray colors, depending on presence or absence of iron oxide, clay, lime, silica and carbon impurities. Under the microscope, gypsum contains granular, fibrous or porphyroblastic tissues.
What is gypsum made of?
What is gypsum? Gypsum, or calcium sulfate dihydrate, is a very soft mineral with the chemical formula CaSO 4 ·2H 2 O, also known as “aqueous calcium sulfate”. In fact, gypsum is the same as natural hydrated calcium sulfate found in several crystalline forms.
How much water is in gypsum?
Pure gypsum contains 9.20% water, 6.46% So3 and 5.32% Cao. According to ASTM International, the minimum purity required for gypsum in industrial cases is 70% gypsum. However, most commercial types of gypsum contain 75 to 95% purity.
How hot is gypsum?
Having been extracted from mines such as lime, gypsum, is heated inside special furnaces up to about 180 °C until water molecules lose 2/3 of their crystallization and can be used as moldable gypsum in construction of buildings.
Can gypsum be scratched?
Gypsum typically has a layered structure, with a hardness of 5.2. It can be scratched by the fingernail, while the anhydride hardness ranges between 3 and 5.3 and cannot be scratched by the fingernail. Anhydride is converted into gypsum due to its high solubility and dewatering, and is therefore rarely found.
Is gypsum the same as chalk?
In fact, it results in chalk or calcined gypsum. Note that the gypsum available on the market is the same as chalk, different forms of which can be obtained by heating gypsum at different temperatures. The purely complete gypsum is colorless or white.
Is gypsum a mineral?
Gypsum. Gypsum is a common, commercial calcium sulfate mineral. And since calcium sulfate gypsum comprises two water molecules, it has a functionality to molecular water. Gypsum loses about three-quarters of its molecular water at temperatures of about 180 °C and converts into 2H2O / CaSo4, which is called chalk or calcined.
Where is gypsum found?
Commercial quantities of gypsum are found in the cities of Araripina and Grajaú in Brazil; in Pakistan, Jamaica, Iran (world's second largest producer), Thailand, Spain (the main producer in Europe), Germany, Italy, England, Ireland and Canada and the United States.
What is the chemical formula for gypsum?
Alabaster. Fine-grained, slightly colored. Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO. 4·2H2O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard / sidewalk chalk, and drywall.
What is gypsum crystal?
It also forms some of the largest crystals found in nature, up to 12 m (39 ft) long, in the form of selenite.
Where is gypsum deposited?
Gypsum is deposited from lake and sea water, as well as in hot springs, from volcanic vapors, and sulfate solutions in veins. Hydrothermal anhydrite in veins is commonly hydrated to gypsum by groundwater in near-surface exposures. It is often associated with the minerals halite and sulfur.
What is the legal limit for gypsum?
The Occupational Safety and Health Administration (OSHA) has set the legal limit ( permissible exposure limit) for gypsum exposure in the workplace as TWA 15 mg/m 3 for total exposure and TWA 5 mg/m 3 for respiratory exposure over an 8-hour workday.
What is the name of the white gypsum?
A massive fine-grained white or lightly tinted variety of gypsum, called alabaster, has been used for sculpture by many cultures including Ancient Egypt, Mesopotamia, Ancient Rome, the Byzantine Empire, and the Nottingham alabasters of Medieval England. Gypsum also crystallizes as translucent crystals of selenite.
Where are the largest gypsum deposits?
Large open pit quarries are located in many places including Fort Dodge, Iowa, which sits on one of the largest deposits of gypsum in the world, and Plaster City, California, United States, and East Kutai, Kalimantan, Indonesia.
Overview
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. A massive fine-grained white or lightly tinted variety of gypsum, called alabaster, has been used for sculpture by many cultures including Ancie…
Etymology and history
The word gypsum is derived from the Greek word γύψος (gypsos), "plaster". Because the quarries of the Montmartre district of Paris have long furnished burnt gypsum (calcined gypsum) used for various purposes, this dehydrated gypsum became known as plaster of Paris. Upon adding water, after a few dozen minutes, plaster of Paris becomes regular gypsum (dihydrate) again, causing the material to harden or "set" in ways that are useful for casting and construction.
Physical properties
Gypsum is moderately water-soluble (~2.0–2.5 g/l at 25 °C) and, in contrast to most other salts, it exhibits retrograde solubility, becoming less soluble at higher temperatures. When gypsum is heated in air it loses water and converts first to calcium sulfate hemihydrate, (bassanite, often simply called "plaster") and, if heated further, to anhydrous calcium sulfate (anhydrite). As with anhydrite, …
Crystal varieties
Gypsum occurs in nature as flattened and often twinned crystals, and transparent, cleavable masses called selenite. Selenite contains no significant selenium; rather, both substances were named for the ancient Greek word for the Moon.
Selenite may also occur in a silky, fibrous form, in which case it is commonly called "satin spar". Finally, it may also be granular or quite compact. In hand-sized samples, it can be anywhere fro…
Occurrence
Gypsum is a common mineral, with thick and extensive evaporite beds in association with sedimentary rocks. Deposits are known to occur in strata from as far back as the Archaean eon. Gypsum is deposited from lake and sea water, as well as in hot springs, from volcanic vapors, and sulfate solutions in veins. Hydrothermal anhydrite in veins is commonly hydrated to gypsum by groundwa…
Mining
Commercial quantities of gypsum are found in the cities of Araripina and Grajaú in Brazil; in Pakistan, Jamaica, Iran (world's second largest producer), Thailand, Spain (the main producer in Europe), Germany, Italy, England, Ireland, Canada and the United States. Large open pit quarries are located in many places including Fort Dodge, Iowa, which sits on one of the largest deposits of gypsu…
Synthesis
Synthetic gypsum is produced as a waste product or by-product in a range of industrial processes.
Flue gas desulfurization gypsum (FGDG) is recovered at some coal-fired power plants. The main contaminants are Mg, K, Cl, F, B, Al, Fe, Si, and Se. They come both from the limestone used in desulfurization and from the coal burned. This product is pure enough to replace natural gypsum in a wide variety of fields including drywalls, water treatment, and cement set retarder. I…
Synthetic gypsum is produced as a waste product or by-product in a range of industrial processes.
Flue gas desulfurization gypsum (FGDG) is recovered at some coal-fired power plants. The main contaminants are Mg, K, Cl, F, B, Al, Fe, Si, and Se. They come both from the limestone used in desulfurization and from the coal burned. This product is pure enough to replace natural gypsum in a wide variety of fields including drywalls, water treatment, and cement set retarder. Improve…
Occupational safety
People can be exposed to gypsum in the workplace by breathing it in, skin contact, and eye contact. Calcium sulfate per se is nontoxic and is even approved as a food additive, but as powdered gypsum, it can irritate skin and mucous membranes.
The Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for gypsum exposure in the workplace as TWA 15 mg/m for total exposure and T…