Lithium sulphate

Endpoint summary

Additional information

Appearance/physical state/colour

Lithium sulfate and its monohydrate are white, odourless solids at 20 °C and 1013 hPa.

Melting point/freezing point

According to the handbook data the melting point of lithium sulfate anhydrous and its corresponding monohydrate is 860 °C and 130 °C, respectively at atmospheric pressure (1013 hPa).

Boiling point

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex VII, section 7.3, a boiling point study does not need to be conducted, because the melting point of lithium sulfate anhydrous and the corresponding monohydrate is above 300 °C. Lithium sulfate monohydrate loses the hydrated water during heating forming the anhydrous lithium sulfate.

Density

According to handbook and published data, lithium sulfate anhydrous has a relative density of 2.21 and its monohydrate has a relative density of 2.06.

Particle size distribution

The particle size distribution of lithium sulfate and its monohydrate was measured in three studies using volumetric and counted distribution.

The particle size distribution (volume distribution) of the two test items produced the following values:

anhydrous: d10: 11.11 µm, d50: 88.86 µm, d90: 158.76 µm

monohydrate: d10: 33.32 µm, d50: 212.71 µm, d90: 485.92 µm (FMC, 2010)

The particle size distribution of lithium sulfate anhydrous by counted distribution gave the following results:

d10: 0.91 -0.95 µm, d50: 4.56 -5.00 µm, d90: 20.02 -21.64 µm. (Chemetall, 2011)

Differences of the results may depend on the technique of production and / or measurement of particle size distribution incl. sample preparation. Consequently for lithium sulfate anhydrous the percentae of particles <10 µm is in the range of 0 - 20 % according to the available study data.

Vapour pressure

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex VII, section 7.5, the vapour pressure study does not need to be conducted because the melting point of lithium sulfate anhydrous and its monohydrate is above 300 °C.

Partition coefficient

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex VII, section 7.8, the determination of the partition coefficient n-octanol/water is not needed because lithium sulfate anhydrous and its monohydrate are inorganic salts.

Water solubility

The water solubility of lithium sulfate anhydrous and its monohydrate is very good (above 10000 mg/L). For the monohydrate the published data vary between 255 and 349 g/L at 25 °C. For lithium sulfate anhydrous the published water solubility is 342 g/L at 25 °C.

The solubility in water of lithium sulphate (monohydrate) decreases with increasing temperature, as its dissolution is an endothermic process.

Surface tension

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex VII, section 7.6, the determination of the surface tension only needs to be conducted if surface activity is expected or can be predicted. The chemical structure of lithium sulfate anhydrous and its monohydrate does not indicate a surface activity.

Flash point

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex VII, section 7.9, the flash point does not need to be determined, because lithium sulfate anhydrous and its monohydrate are inorganic solids.

Autoflammability

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex VII, section 7.12, a self-ignition temperature study does not need to be conducted as lithium sulfate anhydrous and its monohydrate are not flammable (please refer to section IUCLID 4.13). Further, experience in handling and use gives no indication that the two substances are self-heating up to 400 °C.

Flammability

A flammability test was performed with lithium sulfate anhydrous and its monohydrate (solid state) according to UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, N1: Test Method for readily combustible solids, sub-section 33.2.1.4. Based on this, both substances are classified as non-flammable. (FMC, 2012)

The chemical structures of lithium sulfate anhydrous and its monohydrate do not contain chemical groups, which may lead to the conclusion that the test substances are capable of developing a dangerous amount of (flammable) gas in contact with water. Also, experience in handling and use does not indicate flammability upon contact with water. Further, lithium sulfate anhydrous and its monohydrate do not contain any chemical group that might lead to spontaneous ignition, shortly after coming into contact with air at room temperature (Ref.: R.7a: Guidance on information requirements and chemical safety assessment, EU-Document, 2012).

Further, lithium sulfate and its monohydrate do not meet the criteria for self-reactive substances and organic peroxides.

Explosiveness

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex VII, section 7.11, a study that examines the explosive properties of lithium sulfate was waived as the chemical structures of lithium sulfate anhydrous and its monohydrate do not contain chemical groups or individual structural components, which may lead to the conclusion that the substances possess explosive properties (Re.: 7a: Guidance on information requirements and chemical safety assessment, EU-Document (2012)).

Oxidising properties

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex VII, section 7.13, the chemical structures of lithium sulfate anhydrous and its monohydrate do not contain chemical groups, which may lead to the conclusion that the test substances have oxidising properties.

Stability in organic solvents

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex XI, section 7.15, the determination of the stability in organic solvents and identity of relevant degradation products was waived, because lithium sulfate anhydrous and its monohydrate are inorganic salts.

Storage stability and reactivity towards container material

Corrosion to metals:

In accordance with ECHA guidance on the Application of the CLP Criteria section 2.15, the test has obviously been designed for liquids. Thus, as the substances are solids at room temperature the study was not conducted.

Dissociation constant

The dissociation constant Ksp of lithium sulfate and its monohydrate were calculated using the solubilities (Li2SO4: 342 g/L; Li2SO4*H2O: 349 g/L) and the solubility product. This resulted in a log Ksp of 2.08 and 1.91 (monohydrate), respectively. (SCC, 2012)

Viscosity

Lithium sulfate anhydrous and its monohydrate are solids and therefore the determination of viscosity has been waived (refer to guidance on information requirements and chemical safety assessment, EU-Document, chapter R.7a, 2012).

Additional physico-chemical information

Flammable aerosols:

Section 2.4.2 of Guidance on the application on the CLP Criteria states as follows: “Aerosols, this means aerosol dispensers, are any non-refillable receptacles made of metal, glass or plastics and containing a gas compressed, liquefied or dissolved under pressure, with or without a liquid, paste or powder, and fitted with a release device allowing the contents to be ejected as solid or liquid particles in suspension in a gas, as a foam, paste or powder or in a liquid state or in a gaseous state.” Thus, as the substances do not meet the definition for aerosol, the test was waived.

Gases under pressure:

In accordance with section 1.0 Annex I of Regulation (EC) No 1272/2008, the test does not need to be conducted as the boiling point of the substances are above 20 °C, i.e. the substances are not completely gaseous at 20 °C at standard pressure. Thus, as the substances are not a gas at room temperature, the test was not conducted.