Investigating the Slags of the Metallurgical Plants of Armenia at Fine Grinding

Resumo

In connection with the development of copper and molybdenum production in Armenia, it becomes necessary to develop a technology for processing the slags of the functioning metallurgical plants to extract valuable metals from the slags. It concerns the copper slags of Alaverdi copper-smelting plant with a content of FeO ∼50% and the molybdenum slags of Yerevan Pure Iron Plant with a content of SiO₂ ∼80%. These slags are obtained at high temperatures (with obtaining FeO ⋅ SiO₂, CaO ⋅ SiO₂, Fe₃O₄) and, therefore, they are less active to be used later. Meanwhile, the mentioned slags are rich in iron and silicon oxides and can serve as a cheap raw material for producing iron silicides. The iron silicides can be used in micro- and nanoelectronics, as well as in metallurgy as an alloying additive in the production of steels of special physical and chemical properties. The production of such valuable silicides from an inexpensive raw material is important for Republic of Armenia and is of not only economic, but also ecological significance. To obtain iron silicides, a method of combined aluminothermal reduction of primarily mechanoactivated copper and molybdenum slags is proposed. The preliminary mechanoactivation allows to purposefully affect the structure of the reaction mixture and the parameters of the self-propagating high-temperature synthesis (SHS), thus ensuring the possibility of regulating the structure and the phase composition of the synthesized silicides. In this work, issues on the impact of transformation and phase formation on the morphology of slags of copper and molybdenum production in the functioning metallurgical plants of Armenia at mechanochemical activation by the method of fine grinding in a vibromill are considered. It is shown that at fine grinding (up to 10 μm), the slags, containing small-reactivity complex compounds of iron and silicon (fayalite, magnetite, quarzite) undergo profound chemical changes, transforming into amorphous oxides. The obtained activated oxides can serve as a raw material for producing iron- and silicon-containing alloys—iron silicides.