18 KB304 KB17 KB200020242006Labor, MiroslavMartinac, VanjaPetric, Nedjeljkaštevilka:24 straniletnik:40str. 65-68ISSN:1580-2949COBISSID:424618URN:URN:NBN:SI:doc-96OGGRA2enInštitut za kovinske materiale in tehnologijeMateriali in tehnologijeborov oksidizpiranjemagnezijev hidroksidmagnezijev oksidmorska vodausedanjeB2O3 and CaO in the magnesium oxide from seawater| B2O3 in CaO v magnezijevem oksidu iz morske vode|We have examined the effect of distilled water with a pH of 12.50 during the rinsing of a precipitate of magnesium hydroxide, obtained from seawater by sub-stoichiometric precipitation with 80% of the stoichiometric quantity of dolomite lime as the precipitation reagent. However, with this precipitation method the content of Bsub{2}Osub{3} in the product increases, i.e., magnesium oxide obtained from seawater. The purpose of this study was not onlyto reduce the Bsub{2}Osub{3} quantity as much as possible, but also to determine the minimum number of rinses needed to obtain calcined magnesium oxide with a satisfactory quality. Specifically, boron causes significant disturbances in the electrolysis of magnesium chloride used to obtain metal magnesium if magnesium chloride obtained from seawater is used as the cell charge, and it also adversely affects the quality of the refractory material produced from the sintered magnesium oxide obtained from seawater. The results indicate that if this method of rinsing the magnesium hydroxide precipitate is used, the Bsub{2}Osub{3} content in the MgO samples (80% precipitation) is 0.069 mass %, which is 66% less than the Bsub{2}Osub{3} content in samples prepared without rinsing the magnesium hydroxide with alkalized distilled water (Bsub{2}Osub{3}=0.200 mass %). We found that it is sufficient to carry out the rinsing by decantation three times, as further rinsing does not cause a further reduction in the amount of Bsub{2}Osub{3} in the sample. This rinsing method does not change the CaO content in calcined magnesium oxide, which indicates that further rinsing should be done with non-alkalized distilled waterRaziskan je vpliv destilirane vode s pH 12,50 pri izpiranju usedline magnezijevega hidroksida pridobljenega iz morske vode z nestehiometrijskim obarjanjem in z dodatkom 80 % stehiometrijske količine dolomitnega apna kot obarjalnega reagenta. Pri tem načinu obarjanja je v magnezijevem oksidu povečana vsebnost Bspodaj{2}Ospodaj{3}. Namen dela je bil zmanjšati vsebnost Bspodaj{2}Ospodaj{3} na najmanjšo možno mero in določiti minimalno število izpiranj, da bi nastal kalcinirani oksid zadovoljive kakovosti. Borov oksid povzroča precejšnje motnje pri elektrolizi magnezijevega klorida, če se kot polnilo celice uporabi magnezijev klorid pridobljen iz morske vode. Borov oksid tudi zmanjša kakovost ognjevzdržnega materiala proizvedenega iz magnezijevega oksida pridobljenega iz morske vode. Rezultati raziskave kažejo, da pri standardnem načinu izpiranja usedline magnezijevega hidroksida znaša vsebnost Bspodaj{2}Ospodaj{3} v vzorcih MgO (80%-tno usedanje) 0.069 mas. %, kar je za 66 % manj kot v vzorcih, pripravljenih brez izpiranja magnezijevega hidroksida z bazično destilirano vodo (Bspodaj{2}Ospodaj{3} = 0.200 mas. %). Trikratno izpiranje zmanjša vsebnost Bspodaj{2}Ospodaj{3} na konstantno vrednost, ki se ne spremeni več pri povečanju števila izpiranj. Pri opisanem načinu izpiranja se ne spreminja vsebnost CaO v kalciniranem magnezijevem oksiduTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije