Boiler sands are used in power plants utilizing fluidized bed technology to form a firing grate. The purpose of boiler sands is to form a sand bed in the boiler, which allows the fuel fed into the boiler to burn on top of and within this layer of bed material.
Depending on the application, either circulating or bubbling fluidized bed boilers are used for energy production. The bed material used in these boilers is usually natural sand, or in other words, sand that has been extracted from natural resources and refined to a suitable grain size for use as bed material.
When burning bio fuels, a problem emerges when the alkalis i.e. sodium and potassium, in the biofuel ash react with silica in the natural sand, which results in the sintering of the sand in the boiler environment. Due to this, the flow of the bed material becomes weaker and therefore the bed material needs to be changed continuously by taking part of the used sand out of the boiler and replace it with a new sand.
Today, almost all of the used sands generated by power plants are disposed to the landfills.
Finn Recycling is developing new applications for the used power plant sands. Instead of landfilling, used sands are regenerated and can be used as a raw material for different applications in the building materials industry.