rice husk ash
We manufacture amorphous silica our of rice husk ash , in 25 microns , which is a substitute of microsilica in making high performance concrete .
Rice milling generates a by product know as husk . This surrounds the paddy grain. During milling of paddy about 78 % of weight is received as rice , broken rice and bran .Rest 22 % of the weight of paddy is received as husk . This husk is used as fuel in the rice mills to generate steam for the parboiling process . This husk contains about 75 % organic volatile matter and the balance 25 % of the weight of this husk is converted into ash during the firing process , is known as rice husk ash ( RHA ). This RHA in turn contains around 85 % - 90 % amorphous silica.
So for every 1000 kgs of paddy milled , about 220 kgs ( 22 % ) of husk is produced , and when this husk is burnt in the boilers , about 55 kgs ( 25 % ) of RHA is generated.
India is a major rice producing country , and the husk generated during milling is mostly used as a fuel in the boilers for processing paddy , producing energy through direct combustion and / or by gasification . About 20 million tones of RHA is produced annually. This RHA is a great environment threat causing damage to the land and the surrounding area in which it is dumped. Lots of ways are being thought of for disposing them by making commercial use of this RHA.
The particle size of the cement is about 100 microns . There may be formation of void in the concrete mixes , if curing is not done in properly . This reduces the strength and quality of the concrete . Our product – Silpozz – which is made out of this RHA is much more finer than cement having very small particle size of 25 microns , so much so that it fills the interstices in between the cement in the aggregate. That is where the strength and density comes from. And that is why it can reduce the amount of cement in the concrete mix .
RHA is a good super-pozzolans . Silpozz can be used in a big way to make special concrete mixes . There is a growing demand for fine amorphous silica in the production of special cement and concrete mixes , high performance concrete , high strength, low permeability concrete, for use in bridges, marine environments , nuclear power plants etc. This market is currently filled by silica fume or micro silica , being imported from Norway and also from Burma . Due to limited supply of silica fumes in India and the demand being high the price of silica fume has risen to as much as US$ 800 / ton in India .