Effect of structural characteristics on impact breakage of agglomerates

Samimi, Abdolreza; Ghadiri, Mojtaba; Boerefijn, R.; Groot, A.; Kohlus, Reinhard

doi:10.1016/s0032-5910(02)00246-2

Cited by 60 publications

(28 citation statements)

References 8 publications

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“…Moisture uptake or loss during storage has been shown to either weaken or strengthen such inter-particle bonding depending on the material type (18,19). The sorption isotherm of milled adipic acid was measured using DVS over the same humidity range of 0 to 90% RH, in which particle size reduction was observed.…”

Section: Influence Of Storage Conditions On Psd and Morphologymentioning

confidence: 99%

Anomalous Particle Size Shift During Post-milling Storage

Kwek

Tan

2007

Pharm Res

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Storage of milled adipic acid below the critical relative humidity led to localised disintegration from the agglomerate surface and particle size reduction, which was not influenced by moisture sorption or loss. This evidence supports that "stress relaxation" mechanism behind particle breakage of post-milled particles. Appropriate storage conditions are important in maintaining the stability of milled powders.

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Section: Influence Of Storage Conditions On Psd and Morphologymentioning

confidence: 99%

Anomalous Particle Size Shift During Post-milling Storage

Kwek

Tan

2007

Pharm Res

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“…They argue that granules are generally complex structures made from many different materials, and that this type of repeat impact testing can characterise the strength of successive 'layers' of a granule. Samimi et al (2003) used a system whereby a large number of granules (3000-4000) were impacted successively on a target. The extent of breakage was then characterised by the ratio of mass above (mother particles) and below (debris) a specific size sieve.…”

Section: Dynamic Strength Of Granulesmentioning

confidence: 99%

“…For example, Salman and Gorham (1997) have investigated the effect of impact velocity, and Subero and Ghadiri (2001) and Samimi et al (2003) have investigated the effect of structure. The deformation of granular material under impact conditions has been investigated by and Fu et al (2004a).…”

Section: Single Particle Impact Testsmentioning

confidence: 99%

“…However, it cannot be measured experimentally, as it is impossible to characterise the internal damage of a granule by counting the number of contacts. Alternative experimental measures have been used to characterise the extent of breakage, including mass loss per impact (Papadopoulos and Ghadiri, 1996;Samimi et al, 2003), extent of breakage (Boerefijn et al, 1998) and fragment size distribution (Arbiter et al, 1969;Subero et al, 1999;Subero and Ghadiri, 2001).…”

Section: Extent Of Breakagementioning

confidence: 99%

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Breakage in granulation: A review

Reynolds

Cheong

et al. 2005

Chemical Engineering Science

133

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“…For the semi-brittle failure mode, the impact breakage of a wide range of materials has been investigated by Ghadiri and co-workers, based on which a mechanistic model of particle chipping has been developed (Ghadiri and Zhang, 2002;Samimi et al, 2003;Samimi et al, 2004;Subero-Couroyer et al, 2005 andOlusanmi et al, 2010). Rozenblat et al (2012) carried out breakage experiments in an impact device for the development and validation of breakage models.…”

Section: Introductionmentioning

confidence: 99%

A method for grindability testing using the Scirocco disperser

Bonakdar

Ali

Dogbe

et al. 2016

International Journal of Pharmaceutics

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In the early stages of development of a new Active Pharmaceutical Ingredient (API), insufficient material quantity is available for addressing processing issues, and it is highly desirable to be able to assess processability issues using the smallest possible powder sample quantity. A good example is milling of new active pharmaceutical ingredients. For particle breakage that is sensitive to strain rate, impact testing is the most appropriate method. However, there is no commercially available single particle impact tester for fine particulate solids. In contrast, dry powder dispersers, such as the Scirocco disperser of the Malvern Mastersizer 2000, are widely available, and can be used for this purpose, provided particle impact velocity is known. However, the distance within which the particles can accelerate before impacting on the bend is very short and different particle sizes accelerate to different velocities before impact. As the breakage is proportional to the square of impact velocity, the interpretation of breakage data is not straightforward and requires an analysis of particle velocity as a function of size, density and shape. We report our work using an integrated experimental and CFD modelling approach to 2 evaluate the suitability of this device as a grindability testing device, with the particle sizing being done immediately following dispersion by laser diffraction. Aspirin, sucrose and -lactose monohydrate are tested using narrow sieve cuts in order to minimise variations in impact velocity. The tests are carried out at eight different air nozzle pressures. As intuitively expected, smaller particles accelerate faster and impact the wall at a higher velocity compared to the larger particles. However, for a given velocity the extent of breakage of larger particles is larger. Using a numerical simulation based on CFD, the relationship between impact velocity and particle size and density has been established assuming a spherical shape, and using one-way coupling, as the particle concentration is very low. Taking account of these dependencies, a clear unification of the change in the specific surface area as a function of particle size, density and impact velocity is observed, and the slope of the fitted line gives a measure of grindability for each material. The trend of data obtained here matches the one obtained by single particle impact testing. Hence aerodynamic dispersion of solids by the Scirocco disperser can be used to evaluate the ease of grindability of different materials.

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Effect of structural characteristics on impact breakage of agglomerates

Cited by 60 publications

References 8 publications

Anomalous Particle Size Shift During Post-milling Storage

Anomalous Particle Size Shift During Post-milling Storage

Breakage in granulation: A review

A method for grindability testing using the Scirocco disperser

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