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Physical & Chemical properties

Water solubility

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Endpoint:
water solubility
Type of information:
other: Brochure data
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Manufacturers data without proof.
Guideline:
other: no data

RM-Freetext:
Solid sodium silicate (lumps or ground glass) is practically insoluble in  water at ambient temperature and pressure.
Solutions containing up to 55% solids in water can be
achieved at elevated temperature and pressure. They are
stable at room temperature.

Endpoint:
water solubility
Type of information:
other: Handbook data
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Peer-reviewed handbook data.
Principles of method if other than guideline:
Handbook data; no further details
GLP compliance:
no
Type of method:
other: Handbook data
Key result
Remarks on result:
other: see Remarks
Remarks:
Solid sodium silicates are very slightly soluble or almost insoluble in cold water. They are best brought into solution by heating with water under pressure. They are less readily soluble in large amounts of water than in small amounts and the anhydrous silicates dissolve with more difficulty than the hydrated silicates. Silicates containing more sodium dissolve more readily.

Solid sodium silicates are very slightly soluble or almost insoluble in cold water. They are best brought into solution by heating with water under pressure. They are less readily soluble in large amounts of water than in small amounts and the anhydrous silicates dissolve with more difficulty than the hydrated silicates. Silicates containing more sodium dissolve more readily.

Endpoint:
water solubility
Type of information:
other: Brochure data
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Product brochure of producers association; data without proof.
Principles of method if other than guideline:
Brochure data; no further details
GLP compliance:
no
Type of method:
other: Brochure data
Key result
Remarks on result:
other: see Remarks
Remarks:
Alkaline silicates are completely insoluble in n-octanol. The pH in alkaline silicates is dependant on the silica to alkali ratio and the concentrations of the individual solutions. Concentrated solutions usually have a pH between 10 and 13.

Alkaline silicates are completely insoluble in n-octanol.

The pH in alkaline silicates is dependant on the silica to alkali ratio and the concentrations of the individual solutions. Concentrated solutions usually have a pH between 10 and 13.

Endpoint:
water solubility
Type of information:
other: expert judgement
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: peer-reviewed expert judgement
Principles of method if other than guideline:
peer-reviewed expert judgement; no further details
GLP compliance:
not specified
Type of method:
other: peer-reviewed expert judgement
Key result
Remarks on result:
other: see Remarks
Remarks:
Powders obtained by water evaporation from solutions are readily soluble in water at room temperature due to their residual water content of about  20%.

Powders obtained by water evaporation from solutions are readily soluble in water at room temperature due to their residual water content of about 20%.

Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well-documented scientific publication.
Principles of method if other than guideline:
Concentration measured colorimetrically using molybdenum blue method.
GLP compliance:
no
Type of method:
other: colorimetry
Key result
Water solubility:
115 mg/L
Temp.:
25 °C
pH:
ca. 7

Amorphous silica which precipitates when alkaline silicate solutions are neutralized has a water solubility of 115 mg/L at 25 °C and neutral pH.

Description of key information

Anhydrous solid dissolves extremely slowly at ambient conditions.

Spray-dried solutions readily dissolve in water.

Solutions are infinitely miscible with water.

Amorphous silica which precipitates when alkaline silicate solutions are neutralized has a water solubility of 115 mg/L at 25 °C and neutral pH.

Key value for chemical safety assessment

Water solubility:
115 mg/L
at the temperature of:
25 °C

Additional information

Determination of quantitative water solubilities is not feasible. Aqueous solutions are characterised by a dynamic polymerisation/hydrolysis equilibrium of monomeric SiO2(aq.), oligomeric silicate ions and polysilicate ions which is strongly pH-dependent.