Ashes from fluidized Bed combustion coal fired Power stations with and without co-combustion of secondary fuels (biomass; other fuels - to be verified in view of ecotoxicological and toxicological tests)

Water solubility

Description of key information

Water solubility test was performed for the test substances, Fluidized Bed Combustion (FBC) Fly Ash and Fluidized Bed Combustion (FBC) Bottom Ash. Flask method was used.
Test was performed according to the Method A.6., Water Solubility, Council Regulation (EC) No.440/2008, Published in O.J. L 142, 2008
The concentration of the substance in the aqueous solution was determined by evaporating a known volume of the saturated solution. Cations were additionally analysed by Inductively Coupled Plasma (ICP) - optical emission spectroscopy.
Testing was performed at the temperature of 20°C.

Additional information

The water solubility was measured for Fly Ash and Bottom Ash separately. Results of water solubility are different due to character of test item´s particles (particle size).

The water solubility of the test substance Fluidized Bed Combustion (FBC) Fly Ash varied from 0.67 to 1.14 g/L at the temperature of 20°C. The composition of the saturated solution was found to be time-dependent. This unexpected behaviour is because the test substance is not a defined chemical entity but is formed as a mixture of various oxides with various levels and kinetics of their dissolution.

Average value of water solubility is 0.719 g/L regarding the last two results only.

 

The water solubility of the test substance Fluidized Bed Combustion (FBC) Bottom Ash is 4.619 g/L at the temperature of 20°C.

Complex inorganic substances like FBC Ashes is not simple mixture. This material is heterogeneous in size and composition on a microscopic/macroscopic scale. The representative result is hardly achievable. The range of water solubility of FBC Ashes is 0.67 to 4.619 g/L at the temperature of 20^oC. FBC Ashes are moderately soluble to soluble.