Reaction mass of Limestone and calcium fluoride and calcium sulfate

Melting point / freezing point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

melting point/freezing point

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Remarks:

peer reviewed

Principles of method if other than guideline:

Data is from handbook, no details are provided.

GLP compliance:

no

Melting / freezing pt.:

825 °C

Atm. press.:

102.5 atm

Decomposition:

yes

Remarks:

- decomposes into CaO and CO2

Decomp. temp.:

825 °C

Remarks on result:

other: Calcium carbonate (aragonite)

Melting / freezing pt.:

1 339 °C

Atm. press.:

102.5 atm

Decomposition:

yes

Remarks:

- decomposes into CaO and CO2

Decomp. temp.:

825 °C

Remarks on result:

other: Calcium carbonate (calcite)

Value from generally accepted authoritative secondary source. No data available for pressure

Conclusions:

A melting point of 825°C is cited for calcium carbonate as aragonite, and 1339°C as calcite.

Executive summary:

A melting point of 825°C is cited for calcium carbonate as aragonite, and 1339°C as calcite, with decomposition into CaO and CO2, in the reliable Sax handbook.

Reference 2

Endpoint:

melting point/freezing point

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Remarks:

peer reviewed

Principles of method if other than guideline:

Data is from handbook, no details are provided.

GLP compliance:

not specified

Melting / freezing pt.:

1 403 °C

Atm. press.:

1 013 hPa

Value from generally accepted authoritative secondary source. No data available for pressure.

Conclusions:

The melting point of calcium fluoride is indicated to be 1403°C

Executive summary:

The melting point of calcium fluoride is indicated to be 1403°C in the reliable Merck Index handbook.

Reference 3

Endpoint:

melting point/freezing point

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Remarks:

peer reviewed

Principles of method if other than guideline:

Data is from handbook, no details are provided.

GLP compliance:

not specified

Melting / freezing pt.:

1 460 °C

Value from generally accepted authoritative secondary source. No data available for pressure

Conclusions:

The melting point of calcium sulfate is specified to be 1460°C

Executive summary:

The melting point of calcium sulfate is specified to be 1460°C in the reliable CRC handbook.

Description of key information

Melting expected in the range 825 - 1460°C for the test substance, with water decomposition followed by partial decomposition of one consituent of the reaction mass.

Additional information

No experimental study is available on the registered reaction mass.

However, reliable literature data is available for the three constituents. For simplification purpose, a single reference was presented in this dossier for each constituent: the value was selected based on reliability of the data source, and when equivalent, where more information was provided.

Calcium fluoride and calcium sulfate melt respectively at ca 1403°C and 1460°C; calcium carbonate will decompose from 825°C, or higher depending on its crystal structure.

Assuming that the solid-to-liquid transition will follow the behaviour of the constituents, the reaction mass is expected to melt in a multi-phase range. Indeed, the test substance contained water. So, upon heating, vaporisation of this impurity is anticipated, followed by the reactions the decomposition of the calcium carbonate. Therefore no single value can be retained as key for purpose of CSA.

Moreover, it should be noted that experimental testing would be difficult to perform, considering that the applicability range of the different methods cited in the OECD guideline goes only up to 1273 K (i.e. 1000°C) in the best case. This means that for higher temperatures, testing would not be technically feasible, or result would have limited accuracy.