Magnesium zirconium oxide

Particle size distribution (Granulometry)

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

August 2014

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well conducted study and sufficient information provided, however, no reference made to guideline and no guideline report available. No data available on GLP compliance.

Principles of method if other than guideline:

Particle size was determined using a Malvern Mastersizer.

GLP compliance:

not specified

Type of method:

Laser scattering/diffraction

Type of distribution:

mass based distribution

Percentile:

other: D80

Mean:

0.9 - 2.66 µm

Remarks on result:

other: St. dev. not reported

Percentile:

D50

Mean:

0.58 - 1.38 µm

Remarks on result:

other: St. dev. not reported

Percentile:

other: D20

Mean:

0.34 - 0.76 µm

Remarks on result:

other: St. dev. not reported

Particle size distribution (Malvern Mastersizer)

	M2.8/-5µm/yellow	M2.8/-2µm/yellow	M3.25/-5µm/white	M3.25/-5µm/yellow	M3.25/-2µm/yellow	M3.5/-5µm/yellow	M3.5/-2µm/yellow
D50 (µm)	0.97-1.38	0.58-0.85	0.97-1.38	0.97-1.38	0.58-0.85	0.97-1.38	0.58-0.85
D20 (µm)	0.54-0.76	0.34-0.54	0.54-0.76	0.54-0.76	0.34-0.54	0.54-0.76	0.34-0.54
D80 (µm)	1.77-2.66	0.90-1.20	1.77-2.66	1.77-2.66	0.90-1.20	1.77-2.66	0.90-1.20

Conclusions:

The median particle size (D50) was determined to be in the range of 0.58-1.38 µm, whereas the D20 and D80 were determined to be in the range of 0.34-0.76 µm and 0.9-2.66 µm, respectively.

Reference 2

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

14 January 2015 - 24 February 2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well conducted study and sufficient information provided, however, no reference made to guideline and no guideline report available. No data available on GLP compliance.

Principles of method if other than guideline:

The particle size distribution was determined using sieve analysis and/or a laser particle size analyser.

GLP compliance:

not specified

Type of method:

other: sieve analysis and laser diffraction

Type of distribution:

mass based distribution

Percentile:

D50

Mean:

> 297 - < 420 µm

Remarks on result:

other: Sample 36FV, sieve analysis

Percentile:

D50

Mean:

> 74 - < 105 µm

Remarks on result:

other: Sample 100FV, sieve analysis

Percentile:

D50

Mean:

< 44 µm

Remarks on result:

other: Sample 325FV, sieve analysis

Percentile:

D50

Mean:

12.66 µm

Remarks on result:

other: Sample 325F, laser PSA

% retained per sample tested using sieve analysis:

	36FV	100FV	325FV
	mesh / %	mesh / %	mesh / %
SV#1	+30: 2.80	+100: 2.10	+325: 6.00
SV#2	+40: 30.10	+140: 36.60	-325: 94.00
SV#3	+50: 25.20	+200: 34.40
SV#4	+70: 14.00	-200: 26.90
SV#5	+100: 9.80
SV#6	+140: 6.30
SV#7	+200: 4.20
SV#8	+325: 3.80
SV#9	-325: 3.80

% retained during sieve analysis and particle size distribution parameters resulting from laser particle size analysis (1 sample only)

	325F
	mesh / %
SV#1	+100: 0
SV#2	+325: 5
SV#3	+325: 95
	µm

d10	1.91
d50	12.66
d90	39.02

Conclusions:

The particle size distribution of four different samples was determined using sieve analysis. Additionally, one of these samples was subject to laser particle size analysis. The d10, d50 and d90 of this last sample were determined to be 1.91, 12.66 and 39.02 µm, respectively. The d50 of the other three samples was estimated to be between 297 and 420 µm, between 74 and 105 µm, and lower than 44 µm, respectively, based on the results of the sieve analysis.

Description of key information

Based on data from two manufacturers (Imerys, 2014; Saint-Gobain, 2015) for a variety of samples with varying MgO content, the mass-based median diameter ranged roughly from 0.58 µm to somewhere between 297 and 420 µm. Magnesia stabilised zirconia are typically crushed and sieved to the desired particle size distribution after production. Therefore, a wide variety of particle size distributions is possible. The data included in this joint dossier are assumed to be representative for this wide range.

Additional information

Magnesium zirconium oxide is typically produced as an ingot or bubble and afterwards the resulting fused material is crushed and sieved to the desired particle size distribution. Two manufacturers provided granulometry data for the joint dossier, i.e. Imerys Fused Minerals and Saint-Gobain. Both manufacturers provided information on particle size distribution for a variety of samples.

For the samples analysed by Imerys (2014), the mass-based median diameter (D50), estimated from mass-based cumulative distribution curves, ranged from about 0.58 to 1.38 µm.

For the samples analysed by Saint-Gobain (2015), mass-based median diameters (D50) were 12.66 µm (for the one sample analysed using laser particle size analysis) and between 297 and 420 µm, between 74 and 105 µm, and < 44 µm, respectively, for the three samples analysed using sieve analysis only.

.