Home > News > Content
Rice Hulls As A Raw Material For Producing Armorphous Silica
Feb 13, 2017

Rice – the primary food source for half the world’s population. Global rice production for 2015 was 740 million metric tons. The protective husk, or hull, surrounding each grain accounts for 20% of the weight.


• Rice Hulls are removed after harvest at a rice processing facility. Modern biomass power plants are fueled by the hulls, returning CO2 captured during rice growth to create a carbonneutral cycle.
• Rice Hull Ash having 90+% solid amorphous silica (SiO2) is collected and fed to the Pörner silica plant for conversion to high quality Liquid Sodium Silicates.

Sodium Silicate is the common name for water-soluble solutions of amorphous silicon dioxide (SiO2) combined with sodium oxide (Na2O) in different proportions. Key properties are controlled by varying the relative amounts of SiO2 and Na2O. Typical ratios for sodium silicate products range from 2.0 to 3.5. Historically, silicates have been produced by melting quartz sand together with sodium carbonate to form a solid silica glass plug, the plug is later liquified inside a high pressure steam reactor.

Major Advantages of Rice Hull Ash:
1. Silica sand prices are rising while the growing rice hull ash supply maintains a low, stable pricing;
2. Production of silicate from rice hull ash requires one-third the energy needed to produce silicate from sand;
3. Silica in rice hulls stays clean over a short growing season,while silica sand has high levels of trace metal contaminants.

SILICA FROM RENEWABLE RESOURCES
1. As the rice plant grows, amorphous silica forms a tough husk, or hull. Rice is harvested and the hulls are removed.
2. Hulls are consumed in a biomass power plant running a carbon-neutral process to generate electricity and rice husk ash.
3. Ash is fed to the silica plant, mixed with dilute caustic and heated. The contents are filtered, then adjusted to a ratio between 1.8 – 3.8.
4. Quality is excellent ! – Naturally pure and clear high value liquid silicates .