Abstract
Coagulation is basically an aggregation process where particles settle under the influence of interfacial forces with electrostatic forces playing a governing role. Although particle morphology consisting of shape and roughness dictates the physical encounter of two particles, their eventual coagulation is not only influenced by columbic forces but also other interfacial forces such as hydrophobic interaction, which affects the extent of aggregation of particles through increasing the distance of interaction. Roughness is well known to increase the effective contact angle on hydrophobic surfaces and also enhance interfacial forces. In this study, the effect of morphology of particles and particularly roughness on the settling velocity and in turn coagulation tendency was investigated. Batch settling tests (BSTs) of different particle morphologies were investigated as a function of pH. Two different morphologies of silica particles were utilized with the same particle size distribution (PSD) including smooth-spherical and rough-spherical (Etched). Rough particles were prepared by acid etching technique using hydrofluoric (HF) at different time intervals (15-300 sec). Etched samples were identified and quantified by optic profilometry. Settling test results showed that the settling velocity of particles in a suspension of 2% solids in the massive settling region is significantly affected by particle morphology of the suspension. Coagulation results further revealed that aggregation of rough particles is faster than smooth-spherical particles. Coagulation results are elucidated on the basis of particle morphology and its effect on distance of separation through hydrophobic forces.
Original language | English |
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Title of host publication | IMPC 2016 - 28th International Mineral Processing Congress |
Publisher | Canadian Institute of Mining, Metallurgy and Petroleum |
ISBN (Electronic) | 9781926872292 |
Publication status | Published - 2016 |
Event | 28th International Mineral Processing Congress, IMPC 2016 - Quebec City, Canada Duration: 11 Sept 2016 → 15 Sept 2016 |
Publication series
Name | IMPC 2016 - 28th International Mineral Processing Congress |
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Volume | 2016-September |
Conference
Conference | 28th International Mineral Processing Congress, IMPC 2016 |
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Country/Territory | Canada |
City | Quebec City |
Period | 11/09/16 → 15/09/16 |
Bibliographical note
Publisher Copyright:© 2017 TAPPI Press. All rights reserved.
Keywords
- Coagulation
- Hydrophobic Forces
- Roughness
- Settling Rate
- Silica