Determination of contact angles of powders by capillaric dewatering of filter cakes

Eratak, Özlem Deniz
Solid-liquid contact angle is an important parameter in many particulate processes of the mineral, ceramic and chemical industries. In particular, modification of the contact angle through surface active agents plays a crucial role in froth flotation of minerals. In the case of flat solid surfaces, direct measurement of the contact angle is possible. However, such flat surfaces can not be obtained with finely divided solids typically encountered in flotation applications. Then, indirect methods based on powder beds as thin layers of powders deposited on glass plates or packed columns are used for the determination of apparent contact angles. This thesis presents an alternative novel method based on the capillaric dewatering of filter cakes for the measurement of the receding contact angle and correlates the contact angles measured as such with column wicking and micro-flotation test results of zircon and rutile mineral particles. The experimental procedure is simple and fast. The results have proven that the proposed method is reliable and give a good measure of the contact angle in the absence and presence of surface active non-wetting agents.


Fabrication of microporous ceramics from ceramic powders of quartz-natural zeolite mixtures
San, O; Abali, S; Hoşten, Çetin (Elsevier BV, 2003-01-01)
The possibility of producing ceramic powders suitable for the fabrication of microporous filters was investigated through the thermal treatment of the powder mixtures of a high-purity (99.09% SiO2) quartz and clinoptilolite type of natural zeolite. The quartz and zeolite, mixed in the ratio of 3:1 by weight, was wet ground in a ball mill, the powder was sieved on a 90-mum screen, and the undersize was dried and sintered in the powder form at the temperatures of 1000, 1100 and 1200degreesC for 7 h in an air ...
Synthesis and characterization of waterborne and phosphorus-containing flame retardant polyurethane coatings
Celebi, F; Aras, L; Gündüz, Güngör; Akhmedov, IM (Springer Science and Business Media LLC, 2003-09-01)
Phosphorus-containing flame retardant water-dispersed polyurethane coatings were produced by incorporating different amounts of a phosphorus compound onto the polyurethane main chain. The novel phosphorus containing compound (phosphorus phenyl dihydroxy) was synthesized in three steps using benzaldehyde, pentaerythritol, phenyl phosphonic dichloride, and acetic acid.
The use of gold and silver nanoparticles for surface enhanced fluorescence (SEF) of Dyes
Öztürk, Tacettin; Volkan, Mürvet; Department of Chemistry (2010)
This study focuses on preparing surface enhanced fluorescence (SEF) substrates for use in the enhancement of the emission signal of rhodamine B and fluorescein dyes. Fluorescence spectroscopy has been widely utilized owing to its high sensitivity. SEF is a process where the interactions of fluorophores with the localized surface plasmons of metal nanoparticles results in fluorescence enhancement, increased photostability and rates of system radiative decay which leads to a decreased lifetime. One of the mos...
Production and characterization of activated carbon from hazelnut shell and hazelnut husk
Çuhadar, Çiğdem; Yücel, Hayrettin; Department of Chemical Engineering (2005)
In this study, the pore structures and surface areas of activated carbons produced from hazelnut shell and hazelnut husk by chemical activation technique using phosphoric acid (H3PO4), at relatively low temperatures (300, 400 and 500oC), were investigated. Raw materials were impregnated with different H3PO4 solutions of 30%, 40%, 50% and 60% by weight. To produce activated carbon, acid impregnated samples were heated; at a heating rate of 20 oC/min to the final carbonization temperature and held at that tem...
Effect of surface treatment on electrical conductivity of carbon black filled conductive polymer composites
Koysuren, Ozcan; Yesil, Sertan; Bayram, Göknur (Wiley, 2007-06-05)
Two different types of surface modifiers, 3-aminopropyltriethoxysilane and formamide, were applied to carbon black (CB) particles to lower electrical resistivity of polymer composites prepared by treated CB. Two different matrices, low-density polyethylene and nylon 6, were chosen to compound with surface modified CB. Surface energy of CB was increased by adding amine or amide functional groups during surface treatment of CB. According to electron spectroscopy for chemical analysis (ESCA), chemical modifica...
Citation Formats
Ö. D. Eratak, “Determination of contact angles of powders by capillaric dewatering of filter cakes,” M.S. - Master of Science, Middle East Technical University, 2005.