What is Magnesia?
All about the versatile raw material magnesium oxide

MAGNESIA is, on the one hand, the name of our company: MAGNESIA GmbH. On the other hand, magne­sia is the syn­ony­mous name of a mineral raw mate­ri­al com­pound that is one of our most important pro­ducts, namely magne­si­um oxide.

Magne­sia, or magne­si­um oxide (MgO), is a mineral com­pound that impres­ses with its unique physico-che­mi­cal pro­per­ties and wide range of appli­ca­ti­ons in medi­ci­ne, cos­me­tics, food tech­no­lo­gy and many tech­ni­cal indus­tries. Magne­si­um oxide con­sists of magne­si­um (Mg²⁺) and oxygen (O²-) and belongs to the group of metal oxides. It occurs as a white, crystal­li­ne powder and is che­mi­cal­ly extre­me­ly stable.

When people talk about peri­c­la­se, they usually mean the mineral stone that is the basis for the natural pro­duc­tion of magne­si­um oxide. Another important source is water with a high mineral content (e.g. the Dead Sea), from which magne­si­um chlo­ri­de is extra­c­ted and pro­ces­sed into magne­si­um oxide.

Extraction of magnesium oxide from mineral stone

Magne­si­um oxide is extra­c­ted in two main ways. Firstly, it is extra­c­ted from natural depo­sits such as the mine­rals magne­si­te, dolo­mi­te or, more rarely, peri­c­la­se. This mineral stone is extra­c­ted in mines and then puri­fied and pro­ces­sed. The aim of this pro­duc­tion stage is to prepare the rock as a raw mate­ri­al for the cal­ci­na­ti­on process.

Extraction of magnesium oxide on the basis of brine

Another way to produce magne­si­um oxide is to use salt water as a start­ing mate­ri­al. For example, magne­si­um chlo­ri­de is obtai­ned from sea­wa­ter, which is then pro­ces­sed into magne­si­um hydr­o­xi­de. The sub­se­quent cal­ci­na­ti­on step pro­du­ces magne­si­um oxide.

The process of calcination of magnesium oxide

In the cal­ci­na­ti­on process, certain raw mate­ri­als such as magne­si­te (magne­si­um car­bo­na­te), dolo­mi­te (calcium magne­si­um car­bo­na­te) or sea­wa­ter (magne­si­um hydr­o­xi­de) are heated at high tem­pe­ra­tures. This releases the bound carbon dioxide and forms magne­si­um oxide. This process begins at tem­pe­ra­tures between 600 °C and 800 °C, which are mode­ra­te by indus­tri­al stan­dards. In this tem­pe­ra­tu­re range, the bound carbon dioxide begins to sepa­ra­te from the mole­cu­lar struc­tu­re and is released. This form of magne­si­um oxide from this stage of cal­ci­na­ti­on is par­ti­cu­lar­ly reac­ti­ve and is often used in che­mi­cal appli­ca­ti­ons, for example as a cata­lyst or sorbent.

At higher tem­pe­ra­tures between 800 °C and 1200 °C, so-called caustic-fired magne­si­um is pro­du­ced, which still has a clear reac­ti­vi­ty and is often used for appli­ca­ti­ons in the food indus­try or phar­maceu­ti­cals. As the tem­pe­ra­tu­re rises, the density of the mate­ri­al increa­ses while the poro­si­ty decrea­ses. The mate­ri­al begins to sinter, making it mecha­ni­cal­ly more stable and less reactive.

At tem­pe­ra­tures between 1200 °C and 2000 °C, sin­te­red magne­sia, also known as dead-burnt magne­sia, is formed. This form has large primary crys­tals, low reac­ti­vi­ty and a high density. Sin­te­red magne­sia is extre­me­ly heat-resistant and inso­lu­b­le in water, which makes it ideal for refrac­to­ry appli­ca­ti­ons, for example in the steel or glass industry.

After heating, the mate­ri­al is cooled in a con­trol­led manner to ensure product quality and prevent rehy­dra­ti­on. The end product is further pro­ces­sed depen­ding on the appli­ca­ti­on: It can be ground, sieved or gra­nu­la­ted to meet the spe­ci­fic requi­re­ments of the respec­ti­ve industry.

Use of magnesium oxide in the pharmaceutical industry

Magne­si­um oxide is a key active ingre­di­ent in medi­ci­ne. As an antacid, it neu­tra­li­zes excess stomach acid and reli­e­ves heartb­urn and indi­ges­ti­on. At the same time, it acts as an osmotic laxa­ti­ve by binding water in the intesti­ne and thus pro­mo­ting bowel emp­ty­ing — a pro­per­ty that is used spe­ci­fi­cal­ly for con­s­ti­pa­ti­on. In inno­va­ti­ve dosage forms such as effer­ve­s­cent tablets or gra­nu­les, highly soluble magne­si­um oxide is used, which offers impro­ved bio­avai­la­bi­li­ty. Rese­arch also focuses on bio­me­di­cal appli­ca­ti­ons: For example, magne­si­um oxide nano­par­tic­les serve as car­ri­ers for tar­ge­ted drug release. Studies have also shown anti-inflamm­a­to­ry effects through the neu­tra­liza­ti­on of free radi­cals, which opens up pro­s­pects for the tre­at­ment of chronic inflamm­a­to­ry diseases.

Use of magnesia as a food additive

In food tech­no­lo­gy, magne­si­um oxide (E530) acts as a mul­ti­func­tion­al addi­ti­ve. It sta­bi­li­zes the pH value in dairy pro­ducts and baked goods, pre­vents powders such as flour or spices from clum­ping tog­e­ther, and serves as a source of magne­si­um for nut­ri­tio­nal enrich­ment. Thanks to its ability to bind mois­tu­re, it also extends the shelf life of dry pro­ducts. In food sup­ple­ments, it covers up to 30% of the daily magne­si­um requi­re­ment per portion and thus sup­ports muscle, nerve and bone health.

Magnesium oxide in nutritional supplements

Magne­si­um oxide (MgO) is a fre­quent­ly used source of magne­si­um in nut­ri­tio­nal and health sup­ple­ments. It is cha­rac­te­ri­zed by a high magne­si­um content of around 60 % and is the­r­e­fo­re often used in tablets, cap­su­les or powders to supply magne­si­um. Alt­hough its bio­avai­la­bi­li­ty is lower than that of other magne­si­um com­pounds, it is still used to support muscle func­tion, nerve acti­vi­ty and energy metabolism.

It is also used in mul­ti­vit­amin and mineral sup­ple­ments and is often com­bi­ned with vitamin B6 to opti­mi­ze absorp­ti­on. Due to its low water solu­bi­li­ty, the bio­avai­la­bi­li­ty of normal magne­si­um oxide is rather low. Nevert­hel­ess, we have a highly soluble magne­si­um oxide in our product port­fo­lio, which com­bi­nes the pro­per­ties of a high magne­si­um content with very good solu­bi­li­ty in liquids. Find out more here!

Magnesium oxide in technical-industrial applications

Magne­si­um oxide is a key raw mate­ri­al for indus­tri­al solu­ti­ons. In the con­s­truc­tion indus­try, refrac­to­ry magne­si­um oxide-panels are used in blast fur­naces or glass pro­duc­tion plants to increase energy effi­ci­en­cy and heat resis­tance. In envi­ron­men­tal tech­no­lo­gy, it neu­tra­li­zes acidic was­te­wa­ter and binds heavy metals such as lead or arsenic, making it an effec­ti­ve agent in was­te­wa­ter tre­at­ment. Current pro­jects are also rese­ar­ching cements con­tai­ning MgO as a low-CO₂ alter­na­ti­ve to con­ven­tio­nal buil­ding materials.

Conclusion on magnesia as a mineral raw material

Magne­sia, or better known as magne­si­um oxide, is an all-rounder with unique product cha­rac­te­ristics. While it stands out in indus­try appli­ca­ti­ons as a fire­pro­of buil­ding mate­ri­al and envi­ron­men­tal savior, nano-tech­no­lo­gi­cal appli­ca­ti­ons with magne­si­um oxide opti­mi­ze the phar­maceu­ti­cal indus­try. Despite its com­pa­ra­tively low bio­avai­la­bi­li­ty, it remains indis­pensable due to its high magne­si­um content and cost effi­ci­en­cy. Future indus­tries such as smart food sup­ple­ments will further increase the rele­van­ce of magnesia.