Production of Gypsum Products

Gypsum is a precious mineral. It is widely used as a building material, with the majority of it manufactured as plaster to paint walls or create decorative materials in structures. A few gypsum ore resources contain up to 80% gypsum, ideal for plaster production. Raw gypsum may be turned into soil conditioner, cement additives, industrial and construction plasters, and wallboard, among other things. Gypsum products’ various properties enable them to be widely used for multiple purposes in daily life. Gypsum, sometimes known as alabaster, has been widely used in sculptures in ancient Rome, Egypt, Byzantine Empire, Mesopotamia, and the Nottingham alabasters in Medieval England.

What is gypsum?

Calcium sulphate dihydrate (CaSO4.2H2O) is the chemical formula for gypsum. It is a white powdered mineral that is abundant in nature. It is mainly used to make dental casts. It includes calcium and sulphur, both of which are linked to oxygen and water.

Gypsums are plentiful minerals that come in various forms, including alabaster, a material used in decoration and architecture. The world’s most extensive gypsum dune field is found at New Mexico’s White Sands National Monument.

Gypsum crystallises as transparent selenite crystals. It occurs as evaporite minerals and as an anhydrite hydration product. This mineral is non-toxic and can benefit humans, animals, plant life and the environment. The bulk of gypsum in North America is used to make gypsum boards or construction plasters.

Gypsum products production

The volume and degree of technology of gypsum processing equipment vary greatly. Some facilities manufacture 1-2 tonnes daily through low-cost processes, while others generate thousands of tonnes daily using highly automated operations.

Gypsum processing consists of five fundamental stages:

1. Excavation is often done by digging up a section of earth in and around the gypsum location using open-cast methods. Shaft or drift mining may be required to reach deeper reserves. Digging and drilling equipment is used to extract gypsum ores in phases.
2. Crushing: The next step is crushing gypsum rocks. It is recommended before further processing, primarily if future heating will be accomplished in pans and not in any shaft kilns. The gypsum gets reduced to granules no larger than a millimetre in diameter. The jaw crusher is the most common crushing plant used to reduce the size of large bulk material.
3. Screening: After that, a sieve removes big grains that were not fully crushed and may contain contaminants.
4. Grinding using a hammer mill, a ball or rod, is required if the processed gypsum is for high-grade plasterwork, medical, moulding or industrial purposes. In contrast to other cement, such as lime and portland cement, grinding gypsum does not require specific mills.
5. Heating: The last step involves heating, which may be accomplished in a variety of methods, each with a different technology and cost. The ingredients will be dewatered using a rotary drier, and the finished gypsum powder will be collected using a cyclone collector for final use.

There are various gypsum products such as plasters, ceilings, building blocks, solid bricks, cylindrical samples etc. 

Desirable characteristics of gypsum products

Gypsum and gypsum materials are utilised in the building industry. Gypsum is also used to make ceramics, moulds and other items. Many of gypsum’s properties make it the ideal material for specific construction and architectural applications. 

Primarily, it has a smooth consistency. Apart from that it is valued for its accuracy, dimensional stability, reproducibility, strength, abrasion resistance, compatibility with imprint materials, colour, biological safety, cost and ease of use.

Varieties of gypsum products

 The chemical component calcium in gypsum is sulphate-containing water. Selenite, satin spar, and rock gypsum are the three types of gypsum.

Selenite has flat, diamond-shaped crystals that may be separated into thin sheets and is found across the Red Hills. Satin spar is white or pink, fibrous and has a silky gloss. Satin spar can be found in thin layers in rock gypsum and some types of shale beds. Kansas has a lot of rock gypsum. It is mined in the Red Hills of south-central Kansas and northeastern Kansas as thick beds or layers of sedimentary rock.

Conclusion

Natural gypsum will continue to fulfil most of the gypsum industry’s raw material requirements, followed by FGD gypsum. The usage of purified phosphogypsum is the most important potential of other synthetic gypsums other than FGD gypsum. Following that, there is some promise in the usage of refined titanogypsum.

In the past, both the phosphoric acid and titanium dioxide sectors in Europe have displayed a systematic closure of manufacturing sites. Investments in either purifying the generated gypsums or finding uses for the produced gypsums may be necessary for the future viability of these locations.