Synthetic wollastonite

Melting point / freezing point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Testing was conducted between 10 March 2010 and 26 March 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

GLP compliance:

yes

Type of method:

other: Differential scanning calorimetry (DSC)

Melting / freezing pt.:

723 K

Remarks on result:

other: No evidence of melting

Conclusions:

The test material was determined to have a melting temperature greater than 723 K (equivalent to > 450°C). There was no evidence of melting

Reference 2

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Testing was conducted between 10 March 2010 and 26 March 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

The use of data derived for Soda-ash flux calcined kieselghur are justified for read-across to synthetic wollastonite. Justification for read-across is warranted given the similarities in toxicity profile and physico-chemical properties for Soda-ash flux calcined kieselghur and synthetic wollastonite.
Considering the available data:
The source substance show no concerns for the environment.
The source substance has low acute toxicity and low toxicity in repeated dose studies, is non-irritant (skin and eye), non-sensitizing, non-mutagenic to bacteria, non-cytogenic and has low toxicity for reproductive and developmental toxicity.
Please see RAAF attached in Section 13. for further details.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

GLP compliance:

yes

Type of method:

other: Differential scanning calorimetry (DSC)

Melting / freezing pt.:

723 K

Remarks on result:

other: No evidence of melting

Conclusions:

The test material Soda-ash flux calcined kieselghur was determined to have a melting temperature greater than 723 K (equivalent to > 450°C). There was no evidence of melting.
Justification for read-across is warranted given the similarities in toxicity profile and physico-chemical properties for Soda-ash flux calcined kieselghur and synthetic wollastonite.

Reference 3

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

GLP compliance:

not specified

Specific details on test material used for the study:

Synonyms
Calcium metasilicate, wollastonite, calcium hydrosilicate, calcium monosilicate, calcium salt of silicic acid, Caflo E, Calsil, CS Lafarge, Micro-Cel, Silene EF.

Appearance and odor
Calcium silicate is a noncombustible, white or cream-coloured, free-flowing powder that is prepared commercially from lime and diatomaceous earth; many different calcium silicates occur in nature in mineral form (e.g. wollastonite, afwillite, grammite)

Melting / freezing pt.:

ca. 1 540 °C

Conclusions:

The boiling point for calcium silicate was determined to be 1540 deg C.

Reference 4

Endpoint:

melting point/freezing point

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

The use of data derived for calcium oxosilanediolate are justified for read-across to synthetic wollastonite. Justification for read-across is warranted given the similarities in toxicity profile and physico-chemical properties for calcium oxosilanediolate and synthetic wollastonite. Please see RAAF attached in Section 13. for further details.
Considering the available data:
The source substance show no concerns for the environment.
The source substance has low acute toxicity and low toxicity in repeated dose studies, is non-irritant (skin and eye), non-sensitizing, non-mutagenic to bacteria, non-cytogenic and has low toxicity for reproductive and developmental toxicity.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

not specified

Melting / freezing pt.:

ca. 1 540 °C

Conclusions:

The boiling point for calcium silicate was determined to be 1540 deg C.
Justification for read-across is warranted given the similarities in toxicity profile and physico-chemical properties for Soda-ash flux calcined kieselghur and synthetic wollastonite.

Description of key information

A study has not been carried out on Synthetic Wollastonite because plausible literature data is available that shows the melting point to be in the range of 1200-1500 °C (OSHA Occupational Safety and Health Guideline for Calcium Silicate). Furthermore an existing study carried out on the analogue substance Kieselguhr soda ash flux calcined determined a melting point of > 450. As these values are > 300°C, the generation of additional data would have no relevance for risk assessment.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

450 °C

Additional information

The analogue substance Kieselguhr soda ash flux calcined was determined to have a melting temperature greater than 723 K (equivalent to > 450°C). There was no evidence of melting.

Justification for read-across is warranted given the similarities in toxicity profile and physico-chemical properties for Soda-ash flux calcined kieselghur and synthetic wollastonite.