PRESENTATION ON ELECTRICITY

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GYPSUM

GYPSUM

Gypsum is a soft sulfate mineral composed of calcium

sulfate dihydrat, with the chemical formula CaSO4·2H

2O

COLOR- Colorless to white; may be yellow, tan, blue, pink,

brown, reddish brown or gray due to impurities.

MANUFACTURING PROCESS OFCALCINED GYPSUM

The raw material gypsum is sorted and washed with water

for removal of sand and other impurities.

The lumps thus obtained are then dried and powdered in

pulverizer.

The dried gypsum powder is calcined in a rotary drum calciner

at a temperature of 160ºC to 180ºC.

The process of calcination is done over a period of about

2 hours. the temperature so that one and half molecules of

water is removed to convert the gypsum (CaSo4 2 H2O) into

plaster of Paris (CaSo4 ½ H2O).

After cooling the product (plaster of Paris) is further

pulverized to a fineness of 150 mesh and packed in air tight

polythene lined gunny bags to avoid the plaster of Paris from

absorption of moisture.

Raw material

Water

POP

160ºC to 180ºC

washed

crushing

Calcination

about 2 hrs.

packing

Advantage of p o p

It expands very slightly on setting.

It is easy to spread and level.It mixes up easily with water.

It has no appreciable chemical action on paint and does

not cause alkali attack.

Tiles and blocks of plaster of Paris have the specific

advantage of lightness and high fire resistance.

Plaster of Paris gives a decorative interior finish.

Disadvantage of p o p

Gypsum plaster is not suitable for exterior finish as it can

not be used in damp finish.

Cement can not be mixed with plaster of Paris.

It is more expensive than cement or cement lime plaster.

The labor cost for applying plaster of Paris is high.

Gypsum is a rock like mineral commonly found in the

earth’s crust, extracted, processed and used by Man in

construction or decoration in the form of plaster and

alabaster since 9000 B.C.. Plaster was discovered in

Catal-Huyuk in Asia in an underground fresco, and in

Israel Gypsum floor screeds were found from 7000 B.C.

During the time of the Pharaohs, Gypsum was used as

mortar in the construction of the Cheops Pyramid (3000

B.C.). In the Middle Ages and the Renaissance, decorations

and artistic creations were made of plaster. Since then,

the range of construction-related uses have continued to

multiply.

HISTORY OF GYPSUM

Raw material

1.High-quality

gypsum rock is

extracted at

quarries or mine

crusher

2.Large rocks are

crushed into small

pieces

Grinding mill

3.The mill reduces small

rocks to a very fine,

chalk-like powder called

land plaster.

Calcine system

4.The land plaster is

heated in large kettles to

remove most of the water

from the plaster.

Stucco holding tank

5.Calcined land plaster,

called stucco, is fed

from a holding bin to the

mixer by a screw

conveyor.

mixer

6.In the mixer, water is added

back to the stucco

to form a slurry, and foam is

added to the slurry to make

the wallboard more

lightweight.

Forming station

7.T he board forming line starts with two large rolls

of recycled paper or fiberglass mats. The slurry is

poured onto the bottom sheet and is immediately

covered by the facing sheet from the other roll.

Board line

8. the board travels down a

long conveyor line in a single continuous

piece. During this trip, water rehydrates

the stucco, causing it to harden.

Cut –off knife

9. the end of the line, a blade cuts the

hardened board into various lengths.

Transfer table

10.Here the cut lengths are turned

face-side up to protect the face paper

or mat, then fed into the kiln.

11.Kiln

The board kiln completes the

drying process, leaving the gypsum

board virtually moisture-free.

MANUFACTURE OF GYPSUM board

Major varieties of gypsum

Satin spar Pearly, fibrous masses

Selenite Transparent and bladed

crystals

Alabaster Fine-grained, slightly colored

SATIN SPAR ALABASTER ALABASTER Selenite

Type of gypsum:-

Natural gypsum or,

Synthetic gypsum is k/n as fgd.

Uses of gypsum

Gypsum can be used :-

architecture.

Medical.

Agriculture.

Fine art.

Chemical industry.

juice extraction of some fruits and vegetables.

Cosmetic etc.

Use of gypsum in building

Gypsum building materials are used in all construction

types (residential, non-residential, new or refurbished)

Plasterboard

Plasterboard is used for partitions and the lining of

walls, ceilings, roofs. The properties of

plasterboard can be modified to meet specific requirements

, such as fire resistance, humidity resistance, shock

resistance, etc.

Decorative Plaster

Plaster powder, mixed with water, manually or through the

use of silo-supplied spray systems, are used to create

an effective and aesthetically-pleasing lining for brick and

block walls, and for ceilings.

Building plaster

Gypsum plaster is used for walls and ceilings.

Plaster blocks

Gypsum blocks are used for partitions and Gypsum

tiles for ceilings.

Gypsum Fibreboards

Gypsum fibreboard is used for partitions and the lining of

walls, ceilings, roofs and floors. Standard Gypsum

fibreboard offers good performance when it comes to

shock resistance, sound insulation and humidity resistance.

Use of gypsum in medical

Gypsum is also used in the medical industry.

Gypsum is also used to clean teeth and is present

in many forms of toothpaste.

It is used to set the broken bones & sprain.

It is used in filling of teeth cavities.

Use of gypsum in agriculture

Be a source of Calcium and Sulphate Sulphur

for plant growth. Gypsum is added to soil to make the soil better able

to absorb moisture. Gypsum is used in water to settle dirt.

Gypsum board

Gypsum board is the generic name for a family of panel

products that consist of a non-combustible core.

All gypsum panel products contain gypsum cores; however

, they can be faced with a variety of different materials,

including paper and fiberglass mats.

Gypsum board is often called drywall, wallboard, or

plasterboard.

Standard size of gypsum board

Standard size gypsum boards are 48 inches wide and 8, 10, 12 or 14 feet long. The 48 inch width is compatible with standard framing methods in

which studs or joists are spaced 16 inches and 24 inches.

other lengths and widths of gypsum board are available from

the manufacturer on special order.

Gypsum is also an indefinitely recyclable raw material

You can always reuse Gypsum because the chemical composition

of the raw material in the products remains unchanged

the waste of is used to make the same product again.

Properties of gypsum

Gypsum is fire protective

Gypsum is non-combustible and able to delay a fire’s

spread up to 4 hours.

Gypsum regulates sound.

Gypsum walls, ceilings and floors together with

insulation materials create quiet zones in the house

or business environment.

Gypsum is impact resistant.

The Gypsum Industry provides plasterboards, gypsum

fibreboards and plaster blocks with a degree of hardness

equivalent to a thick wall heavy masonry construction.

Gypsum is easy to install and to dismantle

Gypsum is multifaceted, multipurpose, supple and aesthetic

Advantage of gypsum board

Gypsum board walls and ceilings have a number of

outstanding advantages:

Ease of installation

Fire resistance

Sound isolation

Durability

Economy

Versatility

Edges of gypsum board

1.

2.

3.

4.

5.