From raw material to stucco or high-fired plaster – with precisely matched technology


The capabilities of gypsum as a building material depends to a great extent on the chemical composition of the raw material. To ensure targeted, high-quality processing into gypsum plaster, plasterboard or gypsum blocks, you need technology solutions that process natural or synthetic gypsum into stucco or high-fired plaster. With its in-depth know-how, Grenzebach fine-tunes calcination specifically to the nature of the raw material, the properties of the end product, and individual operating parameters such as capacity and available energy sources.

Technology solutions of calcining processes
Wide range of calcining processes

The whole spectrum of calcining processes

Technology solutions:

Grenzebach provides a wide range of calcining processes for optimally coordinated further processing of gypsum. From directly to indirectly heated long-time or short-time calcining systems, Grenzebach covers all processes used in the gypsum industry. With systems such as mill calcining systems for combined grinding and calcining, the rotary kiln, the kettle, and the rotary tubular calciner, as well as continuous autoclaves for the production of alpha hemihydrate, Grenzebach supports its customers so they can optimally process gypsum to ensure that the finished product has the desired qualities.

Roller mill
Gypsum roller mill

Roller mill

The roller mill is a short-time calcining system. Both natural gypsum and mixtures of natural and synthetic raw materials can be ground, dried, calcined and classified in this kind of mill. Bundling several process steps results in highly efficient gypsum processing. Natural gypsum and up to 45% moist FGD gypsum can be fed into a roller mill. Even up to 10% recycled gypsum plasterboard can be used - provided the boards are suitably crushed and the paper is separated from the gypsum core.


Fact-Sheet Roller mill (EN)
Hammer mill
Gypsum hammer mill

Hammer mill

The hammer mill, being a short-time calcining system, grinds, dries, calcines and classifies the raw gypsum in a single step. The resulting stucco is suitable for the production of plasterboard, gypsum fiberboard and gypsum wall blocks. A hammer mill can process 100% moist  FGD gypsum, 100% pre-crushed natural gypsum, or a mixture of both. Recycled gypsum plasterboard that has been crushed and stripped of paper can also be fed into the process. The solution’s advantages include compact design, low capital expense and high energy efficiency.

Fact-Sheet Hammer mill (EN)
Rotary kiln
Gypsum rotary kiln

Rotary kiln

Calcination in a rotary kiln is a direct, long-time calcining process. During the process, the phases of the CaSO4 x H2O system can be optimally adjusted. Rotary kilns are used for the calcining natural gypsum. In this process, pre-crushed natural gypsum is calcined in parallel flow with the flue gas. Fine grinding mills then grind it to its final particle size.


Fact-Sheet Rotary kiln (EN)
Rotary tubular calciners with integrated cooler
Gypsum rotary tubular calciner

Rotary tubular calciners with integrated cooler

Calcination with a rotary kiln calciner is one of the so-called long-time processes for calcining natural or synthetic gypsum. Flue gas or steam is supplied to the gypsum in counterflow and parallel flow via tubes located inside the drum. Due to the large heat transfer surface, the rotary tubular calciner is optimally suited for the production of stucco and high-fired plaster with corresponding phase compositions. 

The calcined gypsum then passes through over an integrated tubular cooler, allowing it to be cooled to the desired finished product temperature.


Stucco drum cooler



The drum cooler has proven its worth in cooling the plaster downstream from the calcining system. Continuous s cooling of the stucco allows consistent production conditions during further processing. Cooling air is fed to the calcined material via tube bundles in a counterflow process, thus cooling the plaster.

Gypsum service raw material analysis and calcining tests

Raw material analysis and calcining tests: The reliable way to the optimum technology solution

Whether natural or synthetic, gypsum is a raw material that is in demand in every form. Regardless of which raw material you use and which gypsum-based building material you want to produce, Grenzebach always offers you the right calcining process. Our experts give you comprehensive advice on the selection of the optimal calcining process based on an exact raw material analysis.

Services for the gypsum production

Our Services for your gypsum production plant


Design, construction, and commissioning of a new gypsum production line are only the first steps in a good customer relationship. Professional service in day-to-day operation is just as important: we want your investment to be consistently profitable – that's why our engineers are there to help and advise you throughout the entire lifecycle of the plant.


Your contact persons

Gypsum processing – a multi-layered process which we tailor to meet your needs. Get in touch!

Karl Aicher

Dennis Schattauer Grenzebach
for all other regions
Dennis Schattauer