Registration Dossier
Registration Dossier
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EC number: 282-217-2 | CAS number: 84144-95-6 Product of silicothermic reduction of molybdic oxide. Composed primarily of fused silica, alumina, and calcium and iron oxides and silicates, with a small amount of residual molybdenum.
Particle size distribution (Granulometry)
Administrative data
Link to relevant study record(s)
- Endpoint:
- particle size distribution (granulometry)
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Company data provided by a major producer, who markets ferromolybdenum slags
- Principles of method if other than guideline:
- In-house sieve analysis using a stack of 10 sieves, sizes: 12.5 mm, 8 mm, 6 mm, 4 mm, 2 mm, 1 mm, 0.5 mm, 0.25 mm, 0,125 mm, 0.063 mm.
- GLP compliance:
- no
- Type of method:
- sieving
- Type of distribution:
- volumetric distribution
- Remarks on result:
- not measured/tested
- No.:
- #1
- Size:
- <= 12.5 mm
- Distribution:
- ca. 99.6 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- No.:
- #2
- Size:
- <= 8 mm
- Distribution:
- ca. 75.6 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- No.:
- #3
- Size:
- <= 6.3 mm
- Distribution:
- ca. 61.2 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- No.:
- #4
- Size:
- <= 4 mm
- Distribution:
- ca. 39.2 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- No.:
- #5
- Size:
- <= 2 mm
- Distribution:
- ca. 20.1 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- No.:
- #6
- Size:
- <= 1 mm
- Distribution:
- ca. 12.1 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- No.:
- #7
- Size:
- <= 0.5 mm
- Distribution:
- ca. 8 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- No.:
- #8
- Size:
- <= 0.25 mm
- Distribution:
- ca. 5.1 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- No.:
- #9
- Size:
- <= 0.125 mm
- Distribution:
- ca. 2.7 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- No.:
- #10
- Size:
- <= 0.063 mm
- Distribution:
- ca. 1.3 %
- Remarks on result:
- other: arithmethic mean of 8 measurements on different batches
- Conclusions:
- Slags, ferromolybdenum-manufg., silicothermic has following particle size distribution:
99.6 % is <= 12.5 mm
75.6 % is <= 8 mm
61.2 % is <= 6.3 mm
39.2 % is <= 4 mm
20.1 % is <= 2 mm
12.1 % is <= 1 mm
8.0 % is <= 0.5 mm
5.1 % is <= 0.25 mm
2.7 % is <= 0.125 mm
1.3 % is <= 0.063 mm - Endpoint:
- particle size distribution (granulometry)
- Remarks:
- dustiness
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- DIN 55992-1 (Determination of a parameter for the dust formation of pigments and extenders - Part 1: Rotation method)
- Version / remarks:
- 2006
- Deviations:
- yes
- Remarks:
- please see below
- Principles of method if other than guideline:
- The Heubach dust meter is modified in a way that a seven stage cascade impactor is connected to the system. This involves an additional air fed of 20L/min via the coarse dust seperator needed to supply the cascade impactor with 40L/min air current as specified in the manufacturer´s specifications.
The calculation report: Grewe, T (2010)
The Multiple-Path Particle Dosimetry Model (MPPD, v2.0; CIIT, 2006) was used to predict this fractional deposition behaviour for workers.
The model algorithms calculate the deposition (and clearance) of mono-disperse and polydisperse aerosols in the respiratory tract for particles ranging from ultra-fine (0.01 microns) to coarse (20 microns) sizes. Within each airway, deposition is calculated using theoretically derived efficiencies for deposition by diffusion, sedimentation and impaction within the airway or airway bifurcation. Filtration of aerosols by the head is determined using empirical efficiency functions. - GLP compliance:
- no
- Type of method:
- rotating drum method
- Remarks:
- a seven stage cascade impactor was connected to a heubach dust meter
- Type of distribution:
- volumetric distribution
- Remarks on result:
- other: p1: 17.2 %, MMAD1 = 9.38 µm, GSD1 = 2.65; p2: 82.8 %, MMAD2 = 30.17 µm, GSD2 = 1.44
- Remarks on result:
- not measured/tested
- Conclusions:
- Total Dustiness (airborne fraction): 38.42 mg/g (experimental result, DMT Report).
Mass median aerodynamic diamaters (bi-modal distribution) of airborne fraction: MMAD1 = 9.38 µm (17.2 %) , MMAD2 = 30.17 µm (82.8 %) (distribution fitted to cascade impactor data, percentale in parentheses indicates weighting factor).
Geometric standard deviation of MMAD: GSD1 = 2.65 , GSD 2 = 1.44
Fractional deposition in human respiratory tract (MPPD model, based on calculated MMAD):
Head (ET): 49.66 %
Tracheobronchial (TB): 0.24 %
Pulmonary (PU): 0.59 %
Referenceopen allclose all
The sieve analysis was conducted with 8 different batches of FeMo slags, which are marketed with the specification 0 -14 mm. The presented results give the percentage (% mass) passing the respective sieve. An arithmetic mean of the 8 measurements is provided. The table below gives the individual results:
| Sample No. | Sieve size → | 12.5 mm | 8 mm | 6.3 mm | 4 mm | 2 mm | 1 mm | 0.5 mm | 0.25 mm | 0.125 mm | 0.063 mm |
| Date | Percentage (% mass) of sample passing the respective sieve | ||||||||||
| Sample 1 | 03.03.2009 | 99.6 | 79.2 | 64.7 | 42.2 | 23.0 | 15.8 | 10.1 | 7.2 | 4.7 | 3.0 |
| Sample 2 | 07.03.2009 | 99.4 | 73.6 | 56.6 | 32.4 | 16.0 | 9.6 | 6.6 | 4.5 | 2.6 | 1.5 |
| Sample 3 | 14.03.2009 | 99.8 | 76.2 | 61.9 | 40.0 | 19.5 | 10.6 | 6.7 | 4.2 | 2.3 | 1.1 |
| Sample 4 | 19.06.2009 | 99.8 | 78.3 | 64.3 | 41.0 | 18.0 | 8.9 | 4.9 | 2.6 | 0.7 | 0.5 |
| Sample 5 | 23.09.2009 | 99.7 | 76.2 | 62.4 | 40.5 | 20.6 | 12.0 | 8.0 | 5.2 | 2.7 | 1.1 |
| Sample 6 | 18.11.2009 | 99.7 | 72.4 | 57.1 | 37.1 | 19.3 | 11.1 | 7.1 | 4.5 | 2.3 | 0.9 |
| Sample 7 | 08.03.2010 | 99.9 | 78.3 | 65.5 | 43.2 | 22.8 | 13.3 | 8.7 | 5.5 | 2.8 | 1.3 |
| Sample 8 | 28.06.2010 | 99.1 | 70.9 | 56.7 | 37.3 | 21.8 | 15.1 | 11.7 | 6.7 | 3.6 | 1.3 |
| Mean | 99.6 | 75.6 | 61.2 | 39.2 | 20.1 | 12.1 | 8.0 | 5.1 | 2.7 | 1.3 | |
Dustiness (airborne fraction): total: 38.42 mg/g.
In the original study report by DMT, a calculation of the mass median diameter was not conducted. Since the deposited fractions were provided for each of the cascade impactor stages, it was possible to fit a bimodal lognormal distribution to the databy standard non-linear regression procedure. As a result, the MMAD and GSD are calculable and reported (p1: 17.2 %, MMAD1 = 9.38 µm, GSD1 = 2.65; p2: 82.8 %, MMAD2 = 30.17 µm, GSD2 = 1.44). As the cascade impactor already takes aerodynamic characteristics of the particles into account, the reported mass median diameter can be interpreted as the mass median aerodynamic diameter.
This figure and the corresponding GSD were used as distribution parameters for the MPPD model enabling an estimation of deposited dust fractions in the human respiratory tract: These fractions were estimated as follows:
Head (ET): 49.66 %
Tracheobronchial (TB): 0.24 %
Pulmonary (PU): 0.59 %
Description of key information
Ferromolybdenum slags are marketed in the form of lumps (ca. fist-size) or granules (up to ca.1-2 cm, partially mixed with sand originating from the reaction vessel, which is lined out with sand). Based on the coarse size, the dustiness is very low.
Additional information
FeMo slags represent solid, glass-like, mostly amorphous materials, basically consisting of oxides of silicon, aluminium, calcium and iron, which solidify from a reaction melt when the temperature drops below ca. 1100 - 1600 °C. After cooling down, the massive slag is broken and crushed. It is marketed in the form of lumps (ca. fist-size) or granules (up to ca.1 - 2 cm, partially mixed with sand originating from the reaction vessel, which is lined out with sand). For the sake of completenss, a sieve analysis and a test for dustiness are provided in the technical registration dossier. Based on the coarse size, the dustiness is very low.
Total Dustiness (airborne fraction): 38.42 mg/g (experimental result, DMT Report).
Mass median aerodynamic diamaters (bi-modal distribution) of airborne fraction: MMAD1 = 9.38 µm (17.2 %) , MMAD2 = 30.17 µm (82.8 %) (distribution fitted to cascade impactor data, percentale in parentheses indicates weighting factor).
Geometric standard deviation of MMAD: GSD1 = 2.65 , GSD 2 = 1.44
Fractional deposition in human respiratory tract (MPPD model, based on calculated MMAD):
Head (ET): 49.66 %
Tracheobronchial (TB): 0.24 %
Pulmonary (PU): 0.59 %
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