Electrokinetic properties of mineral mixtures

نویسنده

  • Jiří Škvarla
چکیده

Elektrokinetické vlastnosti zmesí minerálov Elektroforetický rozptyl svetla (ELS) je nová experimentálna technika umožňujúca merať spectrum elektroforetickej pohyblivosti alebo zeta (ξ) potenciálu skupiny častíc. Toto spectrum odráža distribúciu náboja a čiastočne distribúciu rozmeru týchto častíc. Avšak, okrem modálnej hodnoty napr. zeta potenciálu častíc rovnakého druhu, z ELS spektra môžeme vyčítať aj niektoré ďalšie charakteristiky disperzného systému. Pre vybrané binárne zmesi dobre definovaných koloidných a jemnozrnných častíc SiO2 a SiO2 modifikovaných aminopropylom alebo hematitu (tieto zložky majú odlišné charakteristiky povrchového náboja) boli z ELS spektier určené rozsahy pH vodného prostredia pri ktorých dochádza k heterokoagulácii, heterostabilizácii a heterokoagulačno-heterostabilitnému prechodu týchto častíc. K úplnej heterokoagulácii dochádza ak (jediná) modálna hodnota monomodálneho ELS spectra zmesi leží medzi modálnymi hodnotami ELS spektier individulánych zložiek zmesi pri tom istom pH. Úplná heterostabilita sa naopak uplatňuje keď obidve modálne hodnoty bimodálneho ELS spectra zmesi sa zhodujú s modálnymi hodnotami ELS spektier zložiek pri rovnakom pH. Heterokoagulačnoheterostabilitný prechod bol nakoniec identifikovaný v situácii keď pre zmes sa získalo bimodálne spectrum, avšak aspoň jedna jeho modálna hodnota bola odlišná od modálnej hodnoty ELS spektra niektorej zo zložiek. Takto odhadnuté charakteristiky boli potvrdené výpočtom energetickej bariéry medzi časticami-zložkami.

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تاریخ انتشار 2000