Gypsum is versatile and widespread. It is used as set-regulator for cement, as fertilizer, blackboard chalk, for brewing, baking, tofu manufacture and
much more. A massive fine-grained white or lightly tinted grade of gypsum,
called alabaster, has been used for sculpture by many cultures, including Ancient Egypt for the construction of the pyramids, Mesopotamia, Ancient Rome and the Byzantine Empire. Nottingham carvers in Medieval England also worked with
alabaster. Over the past 3,500 years, it has become one of the most important mineral used in the production of construction materials.

 

Plasterboards rank first in manufacture by calcined gypsum

Today, the majority of gypsum binder, so-called calcined gypsum, is used for the
manufacture of gypsum boards. Also known as plasterboards or drywall, they are
lightweight building elements primarily used as an interior surfacing for
building walls and ceilings. Gypsum board walls and ceilings have a number of outstanding advantages: they are fire-resistant, sound-attenuating, durable, economical and versatile.

 

Yearly 12 billion m2 of wallboard are produced worldwide

Besides standard plasterboards, water-resistant (impregnated) and fireproof boards (fiber-reinforced) are available. Furthermore, special boards such as acoustic, thermal and radiation protection panels are also commercially obtainable. More than 12 billion m2 of wallboard are produced in over 400 plants globally every year. This is more than the surface of the European continent!

 

Gypsum boards production is a highly automated process

Gypsum boards consist of a thin core of gypsum between two cardboard sheets. Their manufacturing process was patented more than 120 years ago, in 1894 by Augustine Sackett. Today, it is a highly automated continuous process. The gypsum core is made of gypsum binder, water, various performance additives and prefabricated foam. Lightweight boards can consist 50 % or more of air.

 

The finished board is ready after less than one hour after mixing the raw materials

All ingredients are mixed for just a few seconds to form a slurry, which is then
poured onto a cardboard sheet, homogenously distributed and covered with a
second cardboard layer. On a long setting-line the gypsum binder chemically
reacts with water. The formed crystalline structure sets and hardens and gives
gypsum boards a certain strength and provides adhesion to the cardboard sheets. After the setting process, boards are cut from the continuous line to the appropriate length and transferred into the dryer. There, excess water is dried out of the boards, resulting in the finished product less than one hour after mixing the raw materials.

 

Efficient production requires suitable retarding and accelerating additives

Quick setting and hardening is of crucial importance to be able to run the gypsum board production at high speed for maximum capacity utilization. Efficient gypsum board production requires a combination of suitable retarding and accelerating additives to achieve the ideal setting curve. This so-called snap set follows the same principle as pushing gas and brake pedals during a car race.
With Sika® Retardan®-200 L, Sika sets a new standard in retarding efficiency,
providing the gypsum industry with the best-performing gypsum retarder
available on the market.

 

Sustainable benefits

Saving energy, reducing CO2 emissions and achieving a sustainable bottom
line in terms of production are ever-present topics that are also gaining
importance in the gypsum industry. In wallboard production today, approx. 70%
of the water added in the mixer is not consumed during gypsum binder reaction
but must be evaporated from the boards.

 

When drying process gets shorter, the carbon footprint is much lower

The board drying process requires a lot of energy, making it the main cost driver of wallboard production. Reducing the water demand with innovative additive
technologies such as Sika® ViscoCrete® helps to cut energy costs. It also reduces the carbon footprint over the entire service life of gypsum boards. The Sika® ViscoCrete® product family includes extremely efficient liquefiers tailored for gypsum applications.

 

Get more details at the GYPSUM website.