SINTEZA BOEHMITA S TERMIČNO OBDELAVO ALUMINIJEVEGA TRIHIDROKSIDA

• Main Author: Lorber, Aleš
• Other Authors: Drofenik, Mihael
• Format: Bachelor Thesis
• Language: Slovenian
• Published: A. Lorber 2012
• Subjects: boksit; bayerjev proces; aluminijev trihidroksid; boehmite; kalcinacija; rotacijska peč; BET; žaro izguba.; bauxite; bayer process; aluminum trihydroxide; calcination; rotary furnace; urn loss.; info:eu-repo/classification/udc/612.57:546(043.2); Gemini; Morali; sami
• Online Access: https://dk.um.si/IzpisGradiva.php?id=36691; https://dk.um.si/Dokument.php?id=47952&dn=; https://plus.si.cobiss.net/opac7/bib/16696854?lang=sl

Diplomska naloga predstavlja raziskavo na področju pridobivanja aluminijevega trihidroksida, njegove predelave ter obdelave in ne nazadnje samega produkta. Dotaknili smo se zgodovine pridobivanja in pridelovanj, ter kako so posamezne faze pridobivala svoja današnja imena. Odkrili smo tudi najbolj značilne oblike struktur posameznih faz aluminijevega trihidroksida in na kratko predstavili njihove strukture. V diplomski nalogi smo predstavili tudi boksit, kako nastaja v naravi, kje so njegova nahajališča in kaj vse lahko iz njega pridobivamo. Gre za surovino brez katere si dandanes življenje težko predstavljamo, saj iz njega pridobivamo številne produkte od aluminijevega oksida, aluminija, tudi železa, germanija, natrija, silicija in številne druge produkte, ki so v današnjem svetu uporabni za najrazličnejše namene. Osnovni proces predelave boksita je skozi zgodovino v osnovi ostal nespremenjen. Imenuje se bayerjev proces, za katerega je leta 1888 patent ustvaril avstrijski kemik Karl Josef Bayer. Skozi zgodovino so se spreminjali le posamezni sklopi in materiali ter naprave, s katerimi se je ta proces izvajal, sam patent pa ostaja enak. Patent je bil izredno veliko odkritje in ga še danes uporabljajo po celem svetu, od Amerike, Evrope, Rusije pa vse do Avstralije. Zraven same predelave boksita in pridobivanja različnih komponent, pa smo se v diplomski nalogi ukvarjali tudi s sodobnimi analiznimi metodami, kot so TGA (termogravimetrijo) in XRD (rentgenska praškovna difrakcija). Le-te smo v sami nalogi podrobno predstavili in jih tudi praktično uporabili pri eksperimentalnem delu. Uporabili smo tudi napravo Gemini VII, ki nam je pomagal pri določanju specifične površine, ki je bila tudi glavna naloga praktičnega dela diplomske naloge, saj smo morali pridobiti aluminijev oksid hidroksid s specifično površino večjo od 250 m2/g. V praktičnem delu diplomske naloge smo se usmerili na aluminijeve trihidroksid, ki smo ga s termično obdelavo skušali predelati tako, da je dobil novo kristalografsko strukturo in tako želeno površino. Termično obdelavo smo opravili v različnih pečeh, glavni cilj pa je bil, iz malih laboratorijskih in pilotnih peči preiti na peč z večji kapacitetami, ki bi nam služila za proizvodnjo termično obdelanega aluminijevega trihidroksida v aluminijev oksid hidroksid s specifično površino večjo od 250 m2/g. Po številnih poskusih smo cilj tudi dosegli in se naučili in dodobra spoznali, kako se material obnaša v posameznih pečeh in pri različnih temperaturah in zadrževalnih časih. The diploma represents a research work considering the synthesis, processing and characterization of aluminum trihydroxide. We discussed the history of the processing of aluminum trihydroxide and find out how the description of each stage of synthesis got its name. We also discovered the most typical phases of aluminum trihydroxide and describe its structures. In the diploma also the bauxite was considered, how it is formed in the nature, where it is located and what can we gain out of it. It is a material that is important for our daily life, because there are a number of different products manufactured out it, as for example: alumina, aluminum, iron, germanium, sodium, silicon and others that are valuable in many different purposes. The basic process of bauxite processing has remained unchanged through the history. It is called the “Bayer process”, the patent for it was launched in 1888 by an Austrian chemist Karl Josef Bayer. Through the history there have been only some minor changes in certain aspects, materials and devices with which the process was implemented, but the patent remained identical. The patent was an amazing discovery and is still applied around the globe in America, Europe, Russia and Australia. In the diploma we also dealt with modern analytical methods as TGA (thermogravimetry) and XRD (X-ray powder diffraction). We presented them in detail and also used them in our experimental work. We used the device Gemini VII, that helped us to determine the specific surface of the product, which was the main task in the practical part of our diploma. During our diploma work we succeeded to obtain aluminum oxide hydroxide with a specific surface, larger as 250 m2/g. In the practical part of the diploma we focused our attention on aluminum trihydroxide which we processed thermally, so that it got a new crystallographic structure which exhibits a intended specific surface. The thermal processing was done in different furnaces. This was consistent with the main goal of the diploma work being, i.e., to develop the processing from small laboratory furnaces to large industrial furnaces with a bigger capacity, which would be used for manufacturing thermally processed aluminum trihydroxide to aluminum oxide hydroxide with the specific surface of 250 m2/g. Here we empirically adjusted in a trial-and-error manner the processing in order to learn how the material behaves in different furnaces at different temperatures and processing times.