26 KB121 KB25 KB199219991999Jurin, OliverLabor, MiroslavMartinac, VanjaPetric, Nedjeljkaletnik:33številka:66 stranistr. 473-478ISSN:1318-0010COBISSID:204714URN:URN:NBN:SI:doc-PQ5LDAA5enInštitut za kovinske materiale in tehnologijeŽelezarna JeseniceŽelezarna RavneŽelezarna ŠtoreKovine zlitine tehnologijeflokulacijaflokulantimagnezijev hidroksidmorska vodausedanjeEffect of 818A and 827N flocculants on seawater magnesia process| Vpliv 818A in 827 flokulanta na proces pridobivanja magnezije iz morske vode|Possibilities for the application of the anionic 818A flocculant (polyacrylamide) produced by the Dutch firm Hercules have been studied in order to increase the settling rate of magnesium hydroxide from sea water and to define the optimum conditions during the precipitation process. The efficiency of the 818A flocculant has been compared to the nonionic 827N flocculant. Examinations were carried out with different degrees of completeness of precipitation and with different quantities of the 818A flocculant. The dependence obtained was described by the appropriate analytical expression. The study has shown that the settling rate is higher during nonstoichiometric precipitation, i.e. precipitation when the quantity added is lower than the stoichiometrically required quantity of the precipitation agent. This has been explained by the Mg(OH)2 partical model. In order to interpret the experimental data obtained by the batch-settling tests a calculation of a continuous thickener was made by applying the Kynch theory. It was observed that at 100% precipitation the quantity of the precipitate obtained was 23.05 ?$kgh^{-1}$?, while that obtained at 80% precipitation was 52.69 ?$kgh^{-1}$?, which indicates a considerable increase in the thickner productive capacity. Thus, it could be seen that the settling rate of the magnesium hydroxide slurry was very important in computing the thickening area requiredPreiskovana je bila uporaba anionskega 818A flokulanta (poliamida) nizozemskega proizvajalca Herkules z namenom povečanja hitrosti usedanja magnezijevega hidroksida iz morske vode in definiranja optimalnih pogojev usedanja. Učinkovitost flokulanta 818A smo primerjali z učinkovitostjo 827N flokulanta. Preiskave so bile nareje pri različnih stopnjah usedanja in različnih količinah dodanega 818A flokulanta. Dobljene odvisnosi so opisane z odgovarjajočimi analitičnimi izrazi. Rezultati preiskave kažejo na znatno povečanje hitrosti usedanja delcev pri nestehiometričnem usedanju, to je, usedanju pri uporabi manjše količine usedalnega sredstva od stehiometrično potrebne količine. Navedeno se pojasnjuje z modelom delca ?$Mg(OH)_2$?. Na osnovi ugotovljenih usedalnih karakteristik suspenzij magnezijevega hidroksida v menzuri pri pogojih diskontinuirnega usedanja, je bil narejen preračun za kontinuirano usedanje z uporabo Kynchove teorije. Pri 100% usedanju se pridobi 23,05, pri 80% usedanju pa 52,69 ?$kgh^{-1}$? magnezijevega hidroksida, kar predstavlja znatno povečanje proizvodnosti usedalnika. Iz ugotovljenega je razavidno, da je hitrost usedanja suspenzije magnezijevega hidroksida zelo važna količina v proračunu potrebne površine usedalnikaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije