A Criterion for Estimating the Strength of Flocculated Aggregates in Salt Solutions
| Autor: | Luís Ayala, Pedro Robles, Edelmira D. Gálvez, Williams H. Leiva, Matías Jeldres, Ricardo I. Jeldres, Pedro G. Toledo |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Flocculation
Materials science kaolin flocculation 0211 other engineering and technologies Mixing (process engineering) 02 engineering and technology Degree (temperature) salinity Composite material 021102 mining & metallurgy Aggregate (composite) food and beverages Geology Mineralogy 021001 nanoscience & nanotechnology Geotechnical Engineering and Engineering Geology Salinity Shear rate Shear (sheet metal) Condensed Matter::Soft Condensed Matter Seawater 0210 nano-technology flocculation mechanism aggregate strength QE351-399.2 flocculation kinetic |
| Zdroj: | Minerals Volume 11 Issue 7 Minerals, Vol 11, Iss 713, p 713 (2021) |
| ISSN: | 2075-163X |
| DOI: | 10.3390/min11070713 |
| Popis: | A simple criterion is proposed to quantitatively estimate the resistance of aggregates based on incremental mechanical shear disturbances. Aggregate strength can be affected by the hydrodynamic conditions under which flocculation occurs therefore, an experimental method is standardized to determine the resistance of aggregate structures that are formed under defined conditions of salinity (NaCl 0–0.1 M), mixing time (3 min), and mean shear rate (G = 273 s−1). Kaolin particles were flocculated in saline solutions with an anionic flocculant of high molecular weight. The method involves increasing the mean shear rate (G = 0–1516 s−1). Each increment represents a new experiment that starts from the base of 273 s−1. Target aggregates are increasingly fragmented as mechanical disturbance increases. The monotonic relationship between the mean shear rate increments (ΔG) and the final size of the aggregates is used for a quantitative estimate of the resistance of the target aggregates since this resistance underlies this relationship. The evolution of aggregate size is analyzed by the Focused Beam Reflectance Measurement (FBRM) method, which may capture the chord length distribution on concentrated slurries. To estimate and compare the resistance of the target aggregates in solutions with different salinities, a pseudo-first-order model that describes the rupture degree as a function of shear rate increments obtains the characteristic shear rate. The rupture percentage is reached with considerably lower agitation increments at higher salinity than at low salinity. This criterion is expected to help improve the efficiency of solid–liquid separation processes, especially in plants operating with seawater, be it raw or partially desalinated. |
| Databáze: | OpenAIRE |
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