Reaction mass of Potassium aluminium tetrafluoride and Dipotassium aluminium pentafluoride monohydrate

Endpoint summary

Additional information

Multiconsituent aluminium potassium fluoride is an inorganic white crystalline solid with melting point above 550 °C (NOTOX, 2010). As the substance is a solid with a melting point well above 300 ˚C, in accordance with Column 2 of REACH Annex VII, studies on boiling point and vapour pressure do not need to be conducted. The relative density of aluminium potassium fluoride is 2.94 at 20 ˚C (NOTOX, 2010). The water solubility of aluminium potassium fluoride is 4.57 g/L at 20 ˚C and pH = 5.8, measured by determining the concentration of aluminium ions in solution (NOTOX, 2010). The studies on octanol/water partition coefficient, flash point and the stability in organic solvents do not need to be conducted as the substance is inorganic. Surface activity is not predicted based on the substance structure; neither is it a desired substance property. As aluminium potassium fluoride is a solid, viscosity is not a relevant property. The substance is not expected to be explosive as it does not contain chemical groups which are associated with explosive properties. The performance of the tests on auto-ignition temperature and flammability is considered to be scientifically unjustified in accordance with Annex XI of REACH, as the substance is incapable of reaction with oxygen due to the fact that metal ions are already present in the highest possible oxidation state, and fluorine, being the most electronegative element, cannot be oxidised by oxygen. Water reactivity and pyrophoric properties are not expected for aluminium potassium fluoride based on the experience in handling the substance. In addition, as the substance is considered to be incapable of reacting exothermically with combustible materials based on its chemical structure, oxidising properties are not expected.

The performance of the study on dissociation constant is considered to be scientifically unjustified in accordance with REACH Annex XI, as, according to Chapter R.7.1.17 of REACH Guidance on information requirements and chemical safety assessment, this property is important for ionisable organic substances. As alumunium potassium fluoride is an inorganic salt, it is expected to dissociate fully into the respective cation and anion in aqueous solution. Possible dissociation of fluoroaluminate moiety, although it may occur upon dissolution, is considered to be irrelevant for this endpoint.

Particle size distribution measurements were performed on aluminium potassium fluoride using laser diffraction method, resulting in the following values: D10 = 0.92 μm, D50 = 3.01 μm, D90 = 11.63 μm (Solvay Fluor GmbH, 2009).