Uses of Gypsum in Industry

by

Roxanne L. Puckett

http://www.emporia.edu/
earthsci/amber/go336/puckett

Image taken from gypsumsolutions.com,
www.gypsumsolutions.com/newscenter/
news/industrial/industrial_plasters.asp

This webpage project was created for a mineralogy course in November 2006 at Emporia State University. The assignment was to learn webpage creation, as well as present a summary of my knowledge regarding the uses of the mineral gypsum in industry.


Image taken from
rockhound.com

Table of Contents

Introduction

The mineral gypsum is surprisingly used widely in industry today.  It is absolutely amazing how such a common mineral could have so many uses in our everyday lives.  Gypsum is used in building construction, agriculture, dental, medical, road construction, art, and as additives in food, pharmaceuticals, and chemicals. Many manufacturers derive their entire business from gypsum and its many uses. How is gypsum manufactured to provide consumers with everyday necessities? This web page will provide an understanding of how important gypsum really is in our world today.

The History of Plaster made from Gypsum

The oldest traces of plaster were found in Anatolia and Syria and date back to 9,000 years age (citation?). About 5,000 years ago, the Egyptians burnt gypsum in open-air fires, then crushed it into powder (citation). Then, this powder was mixed with water to make jointing material for the blocks used in the magnificent Cheops pyramid or monument. The ancient Egyptians used models of plaster taken directly from the human body (citation).

The Greeks used selenite gypsum as windows for their temples because of its transparent quality. The writer Theophraste (372-287 BC) described quite precisely the fabrication of plaster as it was done at that time in Syria and Phenicia (citation).

The Romans also used gypsum to cast thousands of copies of Greek statues (artmolds.com, 2000).

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How Plaster is Made

When gypsum is mixed with water at normal temperatures, it quickly reverts chemically to the preferred dihydrate form, while physically "setting" to form a rigid and relatively strong gypsum crystal lattice:
CaSO4·½H2O + 1½H2O + heat = CaSO4·2H2O
This reaction above is exothermic and is responsible for the ease with which gypsum can be cast into various shapes including sheets, sticks, and molds. There are two ways which this can happen:

Calcination under atmospheric pressure to produce Beta plaster

or

Calcination under elevated pressure to produce Alpha plaster (artmolds.com, 2000).

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Use and Applications

In the construction industry gypsum is used to make sheetrock or also called, wall board because it is the interior wall cover. Sheetrock is very important in our homes, because of its lightweight and tough structure. Gypsum sheetrock acts like insulation and protects homes from heat and cold without the difficulty. A new product, called Hi-Impact brand XP wallboard, is designed for use in wall assemblies in areas where surface durability, impact penetration, moisture, mold and mildew resistance are major concerns (www.gypsumsolutions,
Floor “underlayments” made from gypsum are also used in the building industry. Although this is a new concept in construction, people will be glad to know they have the option of a sound proof apartment. The underlayment is basically a liquid form of plaster that is poured into a mold on the floors of buildings. When it hardens, the sound from footsteps, music, etc. cannot be heard by the people in the floor below.

Architectural ornamentation is also a way gypsum can be used in the building industry. The decoration on a building can basically be cast or sculpted in a very short amount of time, and a small quantity of tools are required when using gypsum plaster. Architectural ornamentation fits into the art industry as well. Artists can cast a readymade object or piece of art to get an, almost perfect, plaster cast duplicate. The artist could also sculpt the art personally from block form (www.gypsumsolutions).

Underlayment image
taken from
www.gypsumsolution

Gypsum is one of those rare minerals that can be used in all categories of soil treatment in the agriculture industry. These treatments include soil amendment, conditioner, and fertilizer. When added to the soil gypsum will stablize soil alkalinity, improve soil structure, build deeper top-soil, break up compacted soil, and allow the soil to dry more quickly after rain or irrigations so that it may be worked sooner. Gyppsum as a fertilizer will make plants and trees more resistant to insects and disease by strengthening their cell walls. Gypsum also promotes water infiltration, retention and conservation. Tests show that farmland treated with gypsum requires up to 33% less water than soils without recent gypsum application (www.nationalgypsum.com/products).

DURACAL® Cement is a gypsum product that dries faster and becomes stronger faster than regular cement. It is used in road construction for mostly above grade repairs such as bridge decks, ramps, and parking lot decks (www.gypsumsolutions, 2006). It is also used in Portland cement and special cement products for set and expansion control.

Other industries that use a smaller amout of gypsum product as a source manufacturing are dentistry and food. The dental industry uses gypsum in plaster form as a model material for tooth restorations. Gypsum is added to some bread and dough mixes as a calcium source and baking aid. The mineral is used as an aid in juice extraction of some fruits and vegetables and is used in many other foods as an economical source of supplemental calcium. It can be used as a tablet cover in pharmaceuticals. In fact, the average person eats about 28 pounds of gypsum in a lifetime! (www.nationalgypsum.com/products).

Conclusion

Many companies derive their entire business from the uses and applications of gypsum. There are even magazines and newspapers that are solely devoted to informing people on what is going on in the industrial gypsum world today. Thanks to this “wonder mineral” people have walls protecting them from the elements and repaired bones after a break, to say the least. One could only wonder what people did before the discovery of gypsum and its many uses.

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Resources

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Related Links
Emporia State University Earth Science at ESU
Return to past GO 336 Student Projects Gypsum: Origins, Properties, and Applications

Created 11/2006. Questions? Email Roxanne Puckett.

Copyright 2006 Roxanne Puckett.