Flame retardants continue to fire demand for MDH

By Laura Syrett
Published: Tuesday, 28 April 2015

Modest end market growth and the gradual appearance of new competitor products for magnesium hydroxide-based fire safety solutions are unlikely to scupper the expansion of this market before 2019, IM discovers.

Growth in sales of consumer products and materials used in building is increasing demand for flame retardants, with mineral-based compounds being among the most popular chemicals for reasons of performance and safety, relative to alternatives such as halogenated chemicals.

Flame retardant additives are widely used in flame resistant plastics, which are needed for applications such as electronics, building insulation, polyurethane foam, and jackets and insulation for wire and cable.

Magnesium hydroxide (MDH) is one of the principal compounds used in this industry. The majority of MDH is made by adding water to caustic calcined magnesia (CCM), but can also be manufactured as a by-product of synthetic magnesia production; from brucite or huntite/hydromagnesite.

In its raw form, MDH is a fine white powder or slurry, which is non-toxic and insoluble, with a low level of transition element impurities. Although it is more expensive on a price per unit basis than its main mineral-based rival, alumina trihydrate (ATH), it is able to withstand higher temperatures (up to around 332°C, whereas ATH decomposes at around 203°C).

As requirements for performance continue to tighten, MDH demand continues to grow. According to Kerry Satterthwaite, senior analyst at Roskill Information Services, this expansion is being driven by the polymers market. 

"We are expecting 6.6% per annum growth for MDH flame retardants worldwide to 2019, driven largely by increased demand for polypropylene and polyamide – the main polymers that have to use MDH rather than ATH, because MDH has better thermal stability," Satterthwaite told IM.

Asia is the largest market for polymers, representing around half of overall consumption, followed by Europe, North America and South America. The growth in Asian consumption, particularly in China, is beginning to slow, however, in step with lower GDP.

Mature markets like Europe and North America are also exhibiting flat to slow growth, with slight changes in this trend usually triggered by regulatory revisions rather than economic factors.

Industry observers believe that new market opportunities exist in South America, but at present this region has shown few signs of implementing the measures required to boost consumption of MDH, or of flame retardants generally.

Global MDH capacity

Roskill has quantified MDH production capacity worldwide as approximately 2.5m tpa. This includes brucite and huntite and is based on output from plants for which production data is available. 

"Most of this – around 1.3m tpa – is brucite, followed by MDH, at 1.1m tpa," Roskill’s Satterthwaite told IM.  "Very small amounts of huntite and hydromagnesite are produced in Greece and Turkey."

As well as flame retardants, the wastewater treatment and flue gas desulphurisation industries also take up a large share of overall MDH output.

According to Roskill, markets for synthetic MDH can be divided into three main categories. Material derived from seawater or brine is used mainly for wastewater treatment and other environmental applications; material derived from serpentine or magnesite is principally consumed in the manufacture of flame retardants and high purity grades of magnesium hydroxide; and thirdly, MDH derived from a variety of sources including magnesite, brines and seawater is used in relatively small amounts in pharmaceuticals and foodstuffs.


MDH often competes with much lower cost alternatives, such as ATH in its flame retardant applications, and lime and caustic soda in some of its other applications.

In the flame retardants industry, most products are required to have a 60 wt.% loading of either MDH or ATH. This therefore represents a significant cost constituent of the final product and these loadings can also compromise other polymer properties.

This situation has created an opportunity for the development of substitute materials. US-based Applied Materials Inc. has launched a range of Dragonite-branded halloysite clay products as cheaper alternatives to MDH, ATH and antimony trioxide, which it claims rivals these materials on performance.

Sweden-headquartered LKAB Minerals, meanwhile, has developed its own competitor material, UltraCarb, which it says is both less expensive and more efficient as a flame retardant than MDH formulations.

However, MDH producers have one eye on the competition and have sought to improve their product offerings to stave off the encroachment of market challengers.

US-based Huber Engineered Materials has introduced a number of high performance products into the market in recent years, including some surface modification products, which it claims address the problem of physical property impairment caused by MDH loadings.

Manufacturers of new types of MDH flame retardants are having to be price sensitive, as fire safety has proven to be an industry where even better-performing products struggle to penetrate markets if they represent a slight increase in costs.

According to Roskill’s analysis, the MDH industry is set to benefit from steady growth for at least the next three years and given that the supply side is also fairly stable, with the ability to adjust capacity where needed, the outlook for MDH is that it will continue to be a niche but significant market for magnesia in the medium term.