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Physical & Chemical properties

Flammability

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Description of key information

Based on a theoretical assessment and on the observed endothermic reactions in the DTA analysis, zirconium basic sulfate is concluded to be non-flammable. Day-to-day handling of the substance shows that the substance is not flammable in contact with water or with air.

Key value for chemical safety assessment

Flammability:
non flammable

Additional information

Flammability is usually seen as the ease with which the substance can burn or be ignited. However it also includes spontaneous flammability (pyrophoricity) and ignition on contact with water.

Pyrophoricity. In the daily use and handling of zirconium basic sulfate during which continuous exposure to air can occur, no spontaneous ignition is observed. The absence of structural alerts furthermore confirms that it is highly unlikely that this substance has pyrophoric properties.

Flammability in contact with water. Under conditions where zirconium basic sulfate is in contact with water no ignition and/or liberation of flammable gases is observed. The absence of structural alerts furthermore confirms that it is highly unlikely that this substance is flammable in contact with water.

Flammability. When zirconium basic sulfate is heated it decomposes. This decomposition becomes significant at approximately 600°C and is preceded at lower temperatures (starting at around 115°C) by dehydration and dehydroxylation. Dehydration and decomposition are endothermic reactions making the substance not liable to burning. Furthermore, inorganic sulfates in which the inorganic element is in its highest possible oxidation state are considered incapable of further reaction with oxygen and can thus be designated as non-flammable. The oxidation state of zirconium in zirconium basic sulfate is in its highest possible state (4+) and this substance can thus be considered as non-flammable.

Justification for classification or non-classification

In the daily use and handling of zirconium basic sulfate during which continuous exposure to air and/or water can occur, no spontaneous ignition and/or liberation of flammable gases is observed.

When zirconium basic sulfate is heated it decomposes. Decomposition being an endothermic reaction makes the substance not liable to burning. Furthermore, zirconium in zirconium basic sulfate is in its highest possible oxidation state (4+) and therefore considered incapable of further reaction with oxygen.

Following the above assessment it is concluded that zirconium basic sulfate is non-flammable and should thus not be classified for this endpoint.