DEVELOPMENT OF ANALYTICAL METHODS FOR DETERMINATION OF ACCOMPANYING COMPOUNDS IN SULPHUR

V diplomski nalogi smo optimirali analizne metode za določitev spremljajočih komponent v žveplu. Poizkušali smo določiti vsebnost anorganskih snovi (pepel) in organskih snovi ter vsebnost kisline, izražene kot delež proste žveplove(VI) kisline v treh različnih vrstah vzorcev – v vzorcih tekočega in trdnega žvepla ter v filtrni pogači. Pri tem smo uporabili klasične analizne metode. Vsebnost anorganskih in organskih snovi smo določili gravimetrično, za določitev deleža proste žveplove(VI) kisline pa smo uporabili volumetrijsko analizo. Vzorcema trdnega žvepla in pogače smo določili tudi vsebnost vlage. Na osnovi dobljenih rezultatov smo ugotovili, da je določitev vsebnosti nečistoč (organskih snovi, pepela in proste H2SO4), katerih delež v vzorcu je majhen, s klasičnimi analiznimi metodami zelo težka. Najbolj primerljive in realne rezultate smo dobili pri določitvi proste H2SO4, kjer smo primerjali rezultate, dobljene s klasično nevtralizacijsko in potenciometrično titracijo. Rezultate smo testirali tudi z Grubbsovim testom za ubežnike, t- testom in F-testom.The diploma thesis optimizes analytical methods for determination of accompanying compounds in sulphur. One of the goals of the thesis was to determine the level of inorganic substances (ash) and organic substances, as well as the level of acid content, regarded as the percentage of free sulphuric(VI) acid in three different sample types, namely in samples of liquid and solid sulphur and of the filter cake. For this analysis the classical analytical methods were employed. The content of inorganic and organic substances was determined gravimetrically, while for the determination of the content level of the free sulphuric(VI) acid the volumetric analysis was employed. The level of moisture content was also determined in the samples of solid sulphur and cake. The results obtained by the analysis clearly show that the determination of impurities (organic substances, ash and free H2SO4), the content of which is rather low, can be very difficult using the classical analytical methods. The most comparable and realistic results were obtained for the determination of free H2SO4, where the results, obtained with the classic neutralisation titration and the potentiometric titration, were compared. The results were tested with the Grubbs test for outliers, the t-test and the F-test