Notch sees opportunities and challenges ahead for rice husk silica

Amherst, Massachusetts – World demand for precipitated silica was 3.1 million tons in 2023, of which tires and non-tire rubber goods represented 37% and 28% of demand respectively, according to Notch Consulting.

Between 2022 and 2027, demand for silica – highly dispersible silica used at high loadings in 'green tire' tread compounds - is expected to show an annual growth rate (AGR) of around 7%, a recent Notch study shows

This compares to growth-rate projections of around 4.9% for 'tires' and 3.8% for mechanical rubber goods (MRGs), noted the US-based market watcher.

Pegged by Notch at around 150 million tonnes, annual production of precipitated silica from rice husk ash “is emerging as a sustainable alternative to conventional silica, especially for tire markets.”

Current leading producers of RHA-based silica for tire markets include China's largest producer of precipitated silica Quechen Silicon Chemical and Yihai Kerry (Wilmar International), a leading Chinese agricultural commodities company.

Notch also noted several smaller RHA-based silica producers in China, India, south east Asia and the US as well as planned new-capacity projects by Evonik, Solvay, OCS and Madhu Silica – major producers of conventional precipitated silica – in 2024.

According to Notch, Evonik, is due to start up a new unit for RHA-based silica at its existing plant in Map ta Phut, Thailand, by yearend 2024.

The German group, which operates a JV with Poerner Group of Austria and Phichit Bio Power (Thailand), "may also roll out RHA technology at its other production sites, Notch also noted.

Solvay is slated to start up a new RHA unit at its existing site in Livorno, Italy also by yearend 2024, with Continental lined up to incorporate the bio-filler in its tires. 

Other planned capacity expansions for RHA-based silica include projects by OSC, which operates four precipitated silica plants in China, Taiwan and Thailand.

OSC is scheduled to bring on a new unit for RHA-silica at its existing plant in Sanyi, Taiwan by the fourth quarter of 2024 and is also considering a new RHA-silica unit in Thailand.

In India, meanwhile, Madhu Silica operates one precipitated silica plant in Gujarat and is set to add another unit at the same site by the yearend.

Madhu Silica also plans to add a second, larger RHA-silica unit at a new location in India in 2025, according to the Notch study.

However, the US firm’s report went on to note certain limitations of RHA-silica in meeting tire industry requirements for sustainable filler materials.

In particular, it said that RHA-silica facilities need to be located close to rice production as it is not cost-effective to ship rice husk ash over long distances.

Cost volatility is another potential factor, Notch citing increasing demand from a range of industries, which could make RHA a more valuable commodity with correspondingly higher prices.

Silicate production, explained Notch, is just one application: RHA also being used, for instance, as a cement additive, in steel production, filtration media, insulation and chemical feedstock.