RESUMO
Interest in magnetic nanoparticles is primarily due to their practical use. In this work, for the production of nanocrystalline powders of pure and gadolinium doped iron oxides, the extraction-pyrolytic method (EPM) was used. As a precursor, either iron-containing extract (iron (III) caproate in caproic acid) or its mixture with gadolinium-containing extract (gadolinium (III) valerate in valeric acid) was used. The mixed precursor contained 0.5 mol %, 2.5 mol %, 12.5 mol %, 50 mol %, and 75 mol % gadolinium in relation to the iron content. The formation of iron oxide phases, depending on the preparation conditions, was investigated. According to the results obtained, it was demonstrated that the presence of more than 2.5 mol % gadolinium additive in the mixed precursor inhibits the magnetite-to-hematite transformation process during thermal treatment. Produced samples were characterized by XRD and SEM methods, and the magnetic properties were studied.
RESUMO
Titanium is widely used in specific applications due to its high strength, low density and good chemical stability. Despite it is one of the most abundant elements in the earth's crust, it is very expensive, because production of pure metallic titanium is very complex. Kroll process is the way how most of the titanium is produced nowadays. Shortages of this process are that it is batch process and it is very energy exhaustive, because titanium sponge material after reduction reaction needs complex post processing to isolate pure titanium. In this work we describe and experimentally investigate technology for Ti production from titanium tetrachloride using combined Kroll and electroslag process. Such process allows to achieve better reaction product separation by molten slag and process can potentially be continuous, thus technological process to produce metallic titanium can be significantly shortened.
