From tyres to footwear: How Brisil is finding new uses for rice husk ash

Rice husk constitutes around 20% of the weight of paddy, which results in millions of tonnes of agricultural waste every year, as per industry estimates. When burned or improperly disposed of, it can contribute to land and air pollution, a big worry during winters in northern India. Conventional production of silica from quartz and sand has also environmental implications, including land degradation, water pollution, and carbon emissions. Brisil Technologies, a Vadodara-based green-tech and advanced materials start-up, has developed a patented process to address these challenges by converting rice husk ash into high-quality precipitated silica that can be used by several industries. Silica is a fine white powder used to harden rubber, improve the grip of tyres, make footwear soles more durable, and act as a thickening or anti-caking agent in products such as paint and toothpaste.

Founded by Tanmay Pandya in 2016, Brisil is working to turn agricultural waste into a commercially viable industrial raw material. Its technology turns rice husk ash into green silica for applications ranging from energy-efficient tyres and footwear to paints, rubber products, and other industrial uses. The company has been operating its commercial plant since 2019 and expanded its annual production capacity to 5,000 tonnes in 2023.

Register for ET MSME Awards 2026 here


For Pandya, the challenge was not simply to extract silica from rice husk ash. It concentrated on creating a process capable of providing consistent quality from a variable waste feedstock while meeting the strict demands of industrial clients. “The biggest challenge was not simply extracting silica but producing a consistent material from a feedstock that varies in composition. Customers have strict requirements, and our product needs to meet those specifications reliably,” he says.

How the process works

Developing the chemistry, refining the process, and translating the technology into commercial manufacturing took the company years of experimentation and operational learning. The process, as described in Brisil’s published patent, begins at rice mills and biomass power plants, where rice husk is burned as fuel in industrial boilers to generate energy, leaving behind rice husk ash as a by-product. Brisil collects this large quantity of ash, which is often dumped as waste and puts it through its patented extraction process to recover the silica it contains, aiming to convert it into a usable industrial material.

In the first step, the ash is treated with an alkaline solution, such as sodium hydroxide, which dissolves the silica and converts it into a liquid known as sodium silicate. The undissolved carbon-rich residue and other impurities are then separated through filtration. In the next stage, sulphuric acid is added to the sodium silicate solution under controlled conditions. This triggers a chemical reaction that causes the silica to separate from the liquid as fine particles through precipitation. The resulting material is then filtered, washed to remove residual chemicals, dried and ground into a fine powder. This powder forms the precipitated silica that can be used in industrial applications such as tyres, footwear and rubber products.

However, maintaining consistency throughout the process remains the biggest challenge, the company points out, as the composition of rice husk ash can vary from one batch to another, affecting the quality of the extracted material. Brisil’s patented innovation lies in how it controls this process to produce highly dispersible silica. Its technology regulates conditions, such as temperature, acidity, and silica concentration during precipitation, influencing the size, porosity, and structure of the resulting particles. This is particularly important for industries such as tyres, where silica must disperse evenly within rubber to deliver its reinforcing properties.

From laboratory innovation to industrial application

For Brisil, the next challenge was to establish that its green silica could compete with conventional alternatives on performance and price. Pandya says sustainability alone is not enough to persuade industrial customers to change suppliers. The material must meet technical specifications and make commercial sense. For example, one of the key applications of Brisil’s highly dispersible silica is in tyre manufacturing. When incorporated into tyre rubber, it can help reduce rolling resistance, lowering the energy required to keep a vehicle moving, while improving grip on wet roads. This combination is important for tyre makers seeking to improve fuel efficiency and safety without compromising performance. Beyond tyres, the company supplies specialised grades for footwear, other rubber products, paints, dental applications, animal feed and fertilisers. It says a key part of its proposition is that customers can replace conventional silica with Brisil’s material without necessarily changing existing formulations or manufacturing processes.

So far, the company has processed more than 3,000 tonnes of rice husk ash and has over 30 customers across India, Southeast Asia, Europe and the Americas. It supplies green silica to global brands, including Adidas and Decathlon, as well as tyre companies across India, Southeast Asia, and Europe. It has also partnered with German chemical company Lehmann&Voss&Co. to evaluate the commercialisation of its biomass-derived silica fillers for tyres, shoe soles, conveyor belts, cables, paints, and plastics.

The wider circular economy opportunity

According to Ankur Nandi, Senior Business Advisor at Greenr Sustainability Accelerator, an initiative of international non-profit organisation TechnoServe, Brisil’s technology addresses two interconnected environmental challenges: agricultural waste disposal and the environmental impact of conventional silica production. “Each year, unsystematic disposal of ash from burning rice husks pollutes the air and land. Meanwhile, conventional silica extraction from quartz and sand leads to significant land degradation, water pollution, and carbon emissions. Brisil’s approach offers an alternative by converting rice husk ash into biosilica for industrial use,” he says. “Brisil’s technology addresses both challenges by converting rice husk ash into biosilica while reducing greenhouse gas emissions by approximately 60%,” he adds.

He further highlights the commercialisation hurdles facing climate-focused technologies. In his view, promising innovations often need to overcome challenges around customer awareness, market adoption, manufacturing capacity, and access to industry partnerships. “While technologies like these offer significant environmental and industrial opportunities, we need to build more pathways for wider adoption of circular economy practices,” Nandi says.

For Brisil, its expanded capacity and growing customer base show progress on that front. The company is now looking to extract more value from rice husk ash through the commercialisation of activated carbon. This could broaden its product portfolio while strengthening the economics of its waste-to-value model. “The larger opportunity is to rethink how industrial materials are produced. Agricultural waste does not have to remain a low-value byproduct. With the right technology, it can become a reliable feedstock for materials serving several industries,” he says.