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Silica from Rice Husk Ash (RHA)

MILLTEC as the market leader has always been striving for continuous improvement to serve customers better and provide good value for their money. Disposal of rice husk is one of the major challenges faced by millers all over India. India produces around 25 million tons of rice husk every year. Burned rice husk is also known as rice husk ash (RHA) is a great environmental threat causing damage to our surroundings and drinking water. But the good part is RHA contains 25% amorphous silica which has widespread application in various industries.

Silica from Rice Husk Ash

As an expansion and diversification strategy, MILLTEC is glad to introduce to millers high-efficiency silica extraction plants from rice husk ash. The equipment for the extraction plants are indigenously designed and manufactured at MILLTEC as per the requirement of the customers. Silica is extracted based on batch processing and MILLTEC offers millers batch processing plants of 2 Tons per day silica extraction capacity.

Along with silica, we can also extract byproducts like activated carbon and sodium carbonate from RHA which are used as raw materials in filtration industry and detergent manufacturing respectively.



  • Silica from Rice Husk Ash is bio-silica and non toxic.
  • Bio-silica is from a waste product and so raw material cost is free.
  • When millers go for cogeneration using rice husk excess steam is best utilized hence cheaper than conventional process of making silica.

Utilization of Rice Husk

Rice husk can be combusted in a boiler to generate steam for cogeneration and process (boiling and drying) requirement, ash generated can be stored for silica extraction. Steam generated is utilized in a steam turbine which generates electricity.

Electricity generated is consumed for mill requirements.

Data on Rice Husk

  • One ton of Paddy generates 200 kgs of Husk
  • 200 kgs of Husk gives 50 kgs of Ash
  • The ash contains 80~90% Silica (ie) 40 kgs silica per ton of paddy.

Process Flow Diagram

Uses Of Silica In Products

Precipitated Silica

  • Rubber reinforcement (Tyre Industry)
  • Plastic reinforcement
  • Agriculture (animal food)
  • Food, healthcare, cosmetics
  • Catalyst; Coatings
  • Pulp and Paper processing
  • Detergents and soaps