dialuminium manganese tetraoxide, spinel type

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29-10-2008 - 15-01-2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Test material

Test material information

Constituent 1

Reference substance name:

Ceramic materials and wares, chemicals

EC Number:

266-340-9

EC Name:

Ceramic materials and wares, chemicals

Cas Number:

66402-68-4

Molecular formula:

MnAl2O4

IUPAC Name:

dialuminium manganese tetraoxide, spinel type

Results and discussion

Water solubility

Water solubility:

< 30 µg/L

Temp.:

20 °C

pH:

> 6 - < 9

Details on results:

Calculated water solubility of the test substance
The water solubility of the test substance at 20 °C was calculated from the determined concentrations of Al and Mn and the content of the elements in the test substance (28.4 % for Al and 32.8 % for Mn). As it was not known, if the dissolved Al- or Mn-concentration originated from the spinel itself or from unreacted starting materials used in the production of the spinel or from impurities, the water solubility was termed water solubility of "test substance equivalents".

Conclusion and interpretation
• The concentration of dissolved Al and Mn in water depends on the loading rate. Higher concentrations of both elements were detected in water when the loading rate was increased from 100 to 1000 mg/L.
• Also the calculated water solubility of the "test substance equivalents" is therefore depending on the loading rate.
• More dissolved Al than Mn is detected in water at the test with a nominal loading rate of 1000 mg/L and more dissolved Mn than Al is detected in the other test, although the content of Mn in the test substance is equivalent that of Al.
• This is interpreted that not the unchanged spinel dissolves in water. More likely is that unreacted starting materials used in the production of the spinel (or Mn and Al-containing impurities) are present in the spinel and that these compounds dissolve relatively more easily than the spinel itself and also than possible Al-compounds.
• The water solubility of the unchanged test substance is the primary aim of the test. The dissolved but unchanged test substance must contain Al and Mn in the proper ratio. It is therefore concluded that the highest possible water solubility of the unchanged spinel has to be based on the lowest calculated "water solubility of test substance equivalents".
• It is also concluded that higher loading rates cause higher concentrations of unreacted starting material or impurities, see above.
The overall result of this study is therefore:
• The water solubility of the "Galaxite" is <0.03 mg / L at 20 °C.
• Mn-compounds and also Al-compounds, which could be unreacted starting materials or impurities, were detected in relatively higher (but still absolutely low) concentrations, and in a loading rate dependent way.
• It is recognized that the water solubility of this test substance may depend on various parameters such as loading rate, pH, dissociation, impurities or the type of agitation of the suspension. Not each of these parameters were know or determined in the scope of this study and therefore the results might change with increasing knowledge.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): insoluble (< 0.1 mg/L)
The water solubility of the "Galaxite" is <0.03 mg / L at 20 °C.
Mean solubility of aluminium: < 0.008 mg/l
Mean solubility of manganese: 0.031 mg/l

Executive summary:

• The water solubility of the "Galaxite" is < 0.03 mg / L at 20 °C.

• Mn-compounds and also Al-compounds, which could be unreacted starting materials or impurities, were detected in relatively higher (but still absolutely low) concentrations, and in a loading rate dependent way. Mean solubility of aluminium: < 0.008 mg/l. Mean solubility of manganese: 0.031 mg/l