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How Magnesium Hydroxide is Made

Magnesium compounds, such as hydroxide, oxide, and carbonate, have unique properties important in various fields. They enhance the efficiency and effectiveness of manufacturing processes, particularly useful where there are acidic waste streams or a need for additional alkalinity and pH buffering.

Magnesium hydroxide, specifically, has been used for centuries as a neutralizer and medicinal ingredient. Magnesium hydroxide is highly stable and safe, making it a popular choice in applications... but where does it come from, and how is it produced?

In this article, we will:

First, The Evolution of Mg(OH)2:

Let us first begin with magnesia, a chemical compound discovered by ancient alchemists, which has an intriguing past. It has been extensively utilized worldwide for centuries as a medicinal ingredient, a crucial manufacturing element, and a valuable raw mineral for neutralizing other elements. Magnesia's various forms, including the element magnesium, were highly coveted in mining operations, royal circles, and apothecaries. Magnesium's compounds, including magnesium hydroxide, oxide, and carbonate, have remarkable properties and versatility that have made them vital in various fields throughout history.

Magnesium is one of the most abundant elements in our solar system and plays a crucial role in the formation of our planet. It is a vital ingredient in the Earth's crust and can also be found in sea and ocean water. In the United States, the state of Nevada is the primary source of magnesium mining. However, magnesite, the mineral form of magnesium, is also extensively mined globally. China, Europe, and Australia are among the leading magnesite producers, with significant deposits spread throughout these regions. The versatility and abundance of magnesium have been shown to impact various industries and applications considerably.

Magnesium Hydroxide, the Industrial Compound:

Magnesium compounds, like magnesium hydroxide, play a crucial role in water and wastewater treatment, fertilizers, and are an essential ingredient in producing ceramics, glass, and various metals. Magnesium hydroxide is also commonly used as a fire retardant for plastics and other materials. Its importance in these industries lies in its ability to enhance the efficiency and effectiveness of complex technical and manufacturing processes where acidic waste streams are present or there is a need for additional alkalinity and pH buffering based on the compound's stability, safety, and effectiveness.

Magnesium Hydroxide, the Pharmaceutical Compound:

Pharmaceutical grade magnesium hydroxide

It is odorless, white, and tasteless, making it an ideal ingredient in many products. The chemical formula of magnesium hydroxide is Mg(OH)2, which gives it a high alkalinity and makes it an effective antacid and dietary supplement. It is also popular in natural deodorants as it balances the body's natural pH and kills odor-causing bacteria without reducing skin moisture or causing skin damage.

Magnesium Hydroxide Production & Sourcing

Magnesium hydroxide, a compound with the chemical formula Mg(OH)2, can be obtained through three distinct methods.

It is important to note that each of the three methods of producing magnesium hydroxide has its unique advantages and disadvantages, and the choice of method depends on various factors such as cost, availability of resources, and environmental impact.

Let's explore these in greater detail:

Examining Brucite as a Natural Source of Magnesium Hydroxide

Mining brucite as a method of sourcing natural magnesium hydroxide

Brucite ore, a natural magnesium hydroxide mineral, was first discovered in 1824 in New Jersey. Being a naturally occurring compound, it has to be located and mined, which can be a tedious and costly process compared to the more easily accessible synthetic alternatives.

Despite the challenges, brucite ore has several significant benefits over synthetic alternatives.

  • It has a higher percentage of magnesium than other raw materials, making it a valuable source for manufacturing magnesium products.

  • The manufacturing process involving brucite ore can be faster (depending on location) and requires less energy, thus reducing production costs as compared to the other methods discussed.

  • Another significant advantage of brucite ore is that it has extremely low carbon dioxide content, which is a contributing factor to climate change when released during mineral processing.

Unfortunately, compared to other magnesium sources, such as dolomite and magnesite, brucite ore is the rarest type of magnesium ore and exists in limited deposits worldwide. Based on current mineral maps, the largest known deposits of brucite ore are located in China and eastern Russia. However, due to the limited availability and high cost of mining brucite ore, it is less widely used than synthetic alternatives. Nonetheless, it remains a valuable resource for manufacturing high-quality magnesium products.

Synthetic Manufacturing of Magnesium Hydroxide through Brine or Seawater Precipitation

Seawater and brine used in the synthetic production of magnesium hydroxide

The most common production method is through precipitation from a combination of seawater or brine and lime (or calcium oxide), which accounts for about 60% of the global supply. The French initially tested this method during the 19th century, and major synthetic producers, including the EU, Japan, and the United States, have further refined it.

This method has significant benefits as it is easily modifiable to meet various application specifications.

Brine and seawater are collected to begin production, often in a specially constructed sump cavern. Seawater can vary in consistency, containing various organic compounds that can complicate the precipitation stage. Similarly, brine obtained from a well or a lake can differ depending on the surrounding geological formations. These initial materials need to be purified to get the ideal composition before the mixing phase. The purification process can involve different methods, such as sedimentation, coagulation, flocculation, and filtration.

Once the materials are purified, they are proportionally mixed to achieve the desired concentration. The mixing is typically done in a series of agitated reactors, which can have different designs depending on the manufacturer. The reactors use a combination of heat, pressure, and agitation to precipitate the magnesium hydroxide out of the solution. The precipitation is helped by adding a flocculant, which aggregates the particles and speeds up the settling.

After the precipitation, the mixture is washed and filtered to remove impurities and obtain a purer product with either water or another solvent, depending on the manufacturer's preference. Different types of filters, such as vacuum, pressure, or centrifugal filters, depend on the volume and characteristics of the mixture.

Finally, the resulting magnesium hydroxide is dried and tested to meet the required quality and purity standards.

Overall, this method, though popular, involves a complex series of steps and demands significant energy.

Hydration of Magnesium Oxide to Create Magnesium Hydroxide

Magnesium hydroxide liquid slurry suspension

This unique process of producing magnesium hydroxide seems straightforward (add water, right?) but is far from and involves several steps. Magnesium carbonate (magnesite) is calcined at high temperatures, losing over 50% of its weight to CO2, producing magnesium oxide (MgO).

Creating magnesium hydroxide involves adding water to the magnesium oxide, often in an agitation tank to accelerate the reaction, which is exothermic (heat producing). Once cooled, the viscosity, solids content, and particle size are carefully and diligently monitored to ensure that it meets all the required specifications.

Hydrating MgO offers a high degree of control over the reaction, allowing for adjustments to be made in real-time to ensure that the final product is of the required quality. This level of control is a significant advantage of the hydration method.

The Garrison Minerals Difference

Garrison Mineral's AlkapHix® Magnesium Hydroxide in a 50lb bag

Garrison Minerals has a wealth of experience in magnesium hydroxide production and boasts an extensive industry network. We are proud to be a leading manufacturer of hydrated magnesium hydroxide, and our meticulous and refined process has earned us a reputation for delivering high-quality products at competitive prices.

Garrison Minerals has the ability to provide magnesium hydroxide from all the production methods listed above. This not only ensures that we can find the method that best suits your organization's budget, production timeline, and quality and sourcing standards but also guarantees that you will receive a solution tailored to your specific requirements.

Additionally, our team of experts is committed to providing exceptional customer service, and we possess the material knowledge, logistics, and project management skills necessary to deliver your ideal solution successfully.


To learn more about these methods and the supply process, contact Garrison Minerals and speak directly with a magnesium hydroxide expert.

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