Silica Produced From Rice Husk Ash. Rice Husk Ash Silica Manufacture. Emerging Investment Opportunities in agriculture waste processing Industry

Silica Produced From Rice Husk Ash

Silica Produced From Rice Husk Ash. Rice Husk Ash Silica Manufacture. Emerging Investment Opportunities in agriculture waste processing Industry


Silica occurs as amorphous to crystalline form in many types of igneous, metamorphic, and sedimentary rocks, but in sediments and sedimentary rocks much of the silica is detrital material. The chief forms of silica are hydrous opal, cryptocrystalline chalcedony, and crystalline quartz.

As a byproduct of the combustion of rice husk to generate energy, rice husk ash (RHA) is formed by silica and carbon, apart from small amounts of other constituents. Several treatments can be used to increase the purity of the silica obtained, or even produce pure silica. Rice Husk Ash. Rice husk ash (RHA) is a highly reactive pozzolan obtained when rice husks are calcinated below the crystallization temperature at 780°C (Yu et al 1999).

Silica is not a new commodity in the plastics market. Its usage as extenders and reinforcing fillers, as pozzolanic material and as glass microspheres for specific engineering applications are well known in the market. Because of its high silica and lignin content, rice husk is tough, woody and abrasive in nature with low nutritive properties and resistance to weathering. With growing environmental concern, open burning has been outlawed in many major rice-producing countries.  18% of the rice husk can be retrieved as ash after the gasification process. Silica content in ash is almost 90% and the rate of recovery of precipitated silica is 90-95% from the rice husk ash if the conversion efficiency is more than 70%. Rice hull ash (RHA) contains over 60% of silica which can be an economically viable raw material for the production of silica based products.

Silica generation is a separate independent process not dependent on electricity generation, although the input ash is dependent on gasification process. Provision will be taken in the design so that external ash is used also as input thus increase silica production.


  • Rubber reinforcement (Tyre industry)
  • Plastic reinforcement
  • Agriculture (Animal food)
  • Food, Healthcare, Cosmetics
  • Catalyst; Coatings
  • Pulp and Paper processing

Market Outlook

Combustion of rice hulls affords rice husk ash (acronym RHA). This ash is a potential source of amorphous reactive silica, which has a variety of applications in materials science. Most of the ash is used in the production of Portland cement. The rice husk ash is a green supplementary material that has applications in small to large scale. It can be used for waterproofing. It is also used as the admixture to make the concrete resistant against chemical penetration. The main applications of rice husk ash in the construction are: High-performance Concrete.

Use of waste or by-products from different industries and the agricultural sector has received increasing attention in the scientific, technology, ecological, economic and social spheres in recent years. Rice husk (RH) is a by-product of rice milling and rice husk ash (RHA) is generated by combustion in a separate boiler. Both RH and RHA are abundantly accessible in rice growing countries such as China, India, Brazil, the USA, and Southeast Asia.

Silica is the major constituent of the rice husk ash. So precipitated silica production will not only provide value addition but also solve the problem of large amount of ash disposal generated from gasification process. With such a large ash content & silica content in the ash it becomes economical to extract silica from the ash, which has wide market & also takes care of ash disposal. Precipitated Silica (also called particulate silica) is composed of aggregates of ultimate particles of colloidal size that have not become linked in massive gel network during the preparation process. It is an amorphous form of silica; the word amorphous denotes a lack or crystal structure, as defined by X ray diffraction.

Early interest in amorphous silica was purely academic. The ash produced after the husks have been burned is high in silica. RHA can be used in a variety of application like: green concrete, high performance concrete, ceramic glaze, water proofing chemicals, roofing shingles, insulator, specialty paints, flame retardants, carrier for pesticides, insecticides & bio fertilizers etc. Precipitated silica is also used as filler for paper & rubber, as a carrier & diluents for agricultural chemicals, as an anti-caking agent, to control viscosity & thickness and as a cleansing agent in toothpastes & in cosmetics. The distinguishing feature of the growth of precipitated silica industry in India is that it has classifiably flourished in the small scale sector. Readily available new materials low capital investment & high rates of return offer a distinct advantage to the small scale manufacturers to venture into this field. There is a very good scope in this sector

The market scope includes silica forms including precipitated, fumed, gels and sols, and micro silica (fumes). Rising demand for the product from the rubber industry is the primary factor driving the market. Increase in demand for tires is mainly driven by rising automotive production, especially in countries such as India, China, Indonesia, South Korea, Japan, Malaysia, Taiwan, Mexico, U.S., and Germany. Rapid economic growth. Silica provides higher abrasion resistance, tensile strength, and flex fatigue properties to rubber products. It is widely used in tire applications, owing to its ability to improve the bond and tear resistance between rubber tires and metallic reinforcements

The growth of silica as a market is driven by its increasing application in paints and coatings. It is mainly utilized in this industry to control rheological characteristics and to aid in the deterrence of rust and corrosion. It is also used as an anti-settling agent and thixotroping agent in the sector. A developing paints and coatings industry in the emerging markets of Asia Pacific, driven by growing construction and automotive sectors, is expected to drive product demand over the forecast period.

Key players

SCR-Sibelco, US Silica Holdings, Emerge Energy Services, Fairmount Santrol, Badger Mining Corporation, Hi-Crush Partners, Saint Gobain, Mitsubishi Corporation, Toyota Tsusho, Pioneer Natural Resources, Tochu, EUROQUARZ GmbH, Guru Metachem Pvt. Ltd. (India), Yihai Kerry Investments Co., Ltd. (China), Usher Agro Ltd. (India), Jasoriya Rice Mill (India), and Rescon (India) Pvt. Ltd, Guru Metachem Pvt. Ltd., Astrra Chemicals, Jasoriya Rice Mill, KGR Agro Fusion (P) Ltd., Kothari Bio Fuels, B.D. Agrotech Pvt. Ltd., KRBL Limited, and J.M. Biotech Pvt. Ltd. Abhiraami Chemicals Ltd, Balls & Cylpebs Ltd, Kiran Global Chems Ltd, Shri Aster Silicates Ltd.

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