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EC number: 269-075-7 | CAS number: 68187-15-5 An inorganic pigment that is the reaction product of high temperature calcination in which praseodymium (III) oxide, praseodymium (IV) oxide, silicon oxide, and zirconium (IV) oxide in varying amounts are homogeneously and ionically interdiffused to form a crystalline matrix of zircon. Its composition may include any one or a combination of the modifiers alkali or alkaline earth halides.
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
![](https://poisoncentres.echa.europa.eu/o/diss-blank-theme/images/factsheets/A-REACH/factsheet/print_physical-and-chemical-properties.png)
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:
- comparable to guideline study with acceptable restrictions
- Remarks:
- Missing data: – Expected percent change of reported values in the future (e.g. variations between production batches) – Lot number – Temperature, pH – Stoke's (effective hydrodynamic) radius Rs distribution for 2 ≤ Rs ≤ 200 μm – Mean value and approximate "area" (percent) of any resolvable peaks in Rs distribution – Percent of particles with Rs ≤ 2 μm – Percent of particles with Rs ≥ 200 μm
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions - Method A: Particle Size Distribution (effective hydrodynamic radius)
- Deviations:
- yes
- Remarks:
- please refer to the field "Rational to reliability incl. deficiencies" above
- GLP compliance:
- no
- Type of method:
- Laser scattering/diffraction
- Type of distribution:
- volumetric distribution
- Remarks on result:
- not measured/tested
- Percentile:
- D10
- Mean:
- 3.3 µm
- Remarks on result:
- other: no data for St. dev.
- Percentile:
- D50
- Mean:
- 9.6 µm
- Remarks on result:
- other: no data for St. dev.
- Percentile:
- D90
- Mean:
- 21.8 µm
- Remarks on result:
- other: no data for St. dev.
- Remarks on result:
- not measured/tested
- Conclusions:
- The particle size distribution of the pigment Zirconium praseodymium yellow zircon was determined using a MALVERN laser diffraction equipment. The size distribution was calculated using the MIE theory in order to interpret the light scattering signal collected by the detectors.
The following values were calculated assuming that the particles are spherical:
d10 = 3.3 µm
d50 = 9.6 µm
d90 = 21.8 µm - Endpoint:
- particle size distribution (granulometry)
- Remarks:
- dustiness
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2009-09-28
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Remarks:
- Heubach-Dust-Meter connected to a cascade impactor
- Qualifier:
- according to guideline
- Guideline:
- DIN 55992-1 (Determination of a parameter for the dust formation of pigments and extenders - Part 1: Rotation method)
- Deviations:
- yes
- Remarks:
- Heubach-Dust-Meter connected to a cascade impactor
- 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 20 L/min via the coarse dust seperator needed to supply the cascade impactor with 40 L/min air current as specified in the manufacturer´s specifications.
The calculation report: EBRC (2009)
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:
- Heubach-Dust-Meter connected to a cascade impactor
- Type of distribution:
- volumetric distribution
- Mass median aerodynamic diameter:
- 22.79 µm
- Geometric standard deviation:
- 3.83
- Percentile:
- D50
- Remarks on result:
- not measured/tested
- Conclusions:
- Total Dustiness (airborne fraction): 44.61 mg/g (experimental results, DMT Report).
Mass median aerodynamic diamater of airborne fraction: MMAD = 22.79 µm (distribution fitted to cascade impactor data).
Geometric standard deviation of MMAD: GSD = 3.83
Fractional deposition in human respiratory tract (MPPD model, based on calculated MMAD):
Head (ET): 48.1 %
Tracheobronchial (TB): 0.8 %
Pulmonary (PU): 0.9 %
A suitable method for determining the PSD of a dry powder to assess the inhalation potential of airborne dust resulting from the handling of that powder is cascade impactor testing (Dustiness). During the cascade impactor testing, the material gets moderately agitated in a rotating drum (to simulate agitation during typical occupational powder handling activities). A constant airstream directs any generated airborne dust to a cascade impactor in which the particles and their agglomerates get separated according to their size.
The aerodynamic PSD is described as being monomodal. With the given parameters it is possible to calculate the cumulated mass percentage of particles at or below 4 µm. This fraction does however not indicate how much is deposited in the deep lung if such aerosol would be inhaled. Instead, the fractional deposition in the human respiratory tract was calculated using the MPPD model.
Thus, only a sub-fraction of 0.9 % particles could deposit in the alveoli of the human lung.
Referenceopen allclose all
The parameters d90, d50and d10are the cut off particle size below which 90 %, 50 % and 10 % of the total particle volume lies. The parameter dv and ds are respectively the volume mean diameter and the surface area mean diameter.
All values are calculated assuming that the particles are spherical.
d10 = 3.3 µm
d50 = 9.6 µm
d90 = 21.8 µm
dv= 11.5 µm
ds= 6.4 µm
Dustiness (airborne fraction): total: 44.61 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 mono modal lognormal distribution to the data by standard non-linear regression procedure. As a result, the MMAD and GSD are calculable and reported (MMAD = 22.79 µm, GSD = 3.83). 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): 48.1 %
Tracheobronchial (TB): 0.8 %
Pulmonary (PU): 0.9 %
Description of key information
Total Dustiness (airborne fraction): 44.61 mg/g (experimental results, DMT Report).
Mass median aerodynamic diamater of airborne fraction: MMAD = 22.79 µm (distribution fitted to cascade impactor data).
Geometric standard deviation of MMAD: GSD = 3.83
Fractional deposition in human respiratory tract (MPPD model, based on calculated MMAD):
Head (ET): 48.1 %
Tracheobronchial (TB): 0.8 %
Pulmonary (PU): 0.9 %
Particle size analysis by laser
diffraction
The following values were calculated assuming that the particles are
spherical:
d10 = 3.3 µm
d50 = 9.6 µm
d90 = 21.8 µm
Additional information
The so-called physical particle size distribution (PSD) was obtained by the laser diffraction method in a wet dispersion after ultrasonic treatment for individualisation of the particles and further mechanical stirring. The particle size of the individualised particles is provided.
Any agglomerates of particles normally existing in the pigment powder were destroyed by (i) the contact with water, (ii) the ultrasonic treatment and (iii) the mechanical stirring. Such agitation of the dry pigment does however not occur under intended and foreseeable manufacture and use conditions and is therefore not suitable to deduce the likelihood of inhalation exposure under workplace conditions.
A suitable method for determining the PSD of a dry powder to assess the inhalation potential of airborne dust resulting from the handling of that powder is cascade impactor testing (Dustiness). During the cascade impactor testing, the material gets moderately agitated in a rotating drum (to simulate agitation during typical occupational powder handling activities). A constant airstream directs any generated airborne dust to a cascade impactor in which the particles and their agglomerates get separated according to their size.
The aerodynamic PSD is described as being monomodal. With the given parameters it is possible to calculate the cumulated mass percentage of particles at or below 4 µm. This fraction does however not indicate how much is deposited in the deep lung if such aerosol would be inhaled. Instead, the fractional deposition in the human respiratory tract was calculated using the MPPD model.
Thus, only a sub-fraction of 0.9 % particles could deposit in the alveoli of the human lung.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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