SCIENTIFIC AND METHODOLOGICAL ANALYSIS OF PROCESSING ALUMINUM SLAG

Processy litʹâ, 2021, Tom 145, №3, p.3-11

Abstract

Received 28.08.202

UDK 669.714.82

The research at the processing of aluminum slags of metallurgical processes which have various chemical compositions has resulted. When creating new metallic materials and technologies for their production, it is important to know and control all the structural and phase transformations that can occur with the material under certain conditions. To date, there is no single universal method that would provide such an opportunity. Therefore, differential thermal analysis (DTA), differential scanning calorimetry (DSC), and a more universal method, synchronous thermal analysis (STA), which additionally includes thermogravimetry (TG), is most often used to study structural and phase transformations during heating and cooling. Therefore, the method of synchronous thermal analysis was chosen for the research. It makes it possible to combine two methods - thermogravimetry and differential scanning calorimetry. The synchronous thermal analyzer STA 449F1 Jupiter from NETZSCH (Germany) was used in the work. The thermal analyzer allows to carry out researches in two modes: "sample" (without taking into account thermophysical characteristics of crucible system) and "sample with correction" (taking into account thermophysical characteristics of crucible). In the "sample" mode, the studies are carried out in comparison with an inert standard, close in thermophysical characteristics to the sample under study. It has also been shown that in some slag samples, several peaks are observed on the differential melting and crystallization curves, which are associated with the formation of the Al-Si eutectic and indicate the presence of other chemical elements in the system in addition to aluminum. The raw material for the production of aluminum by the metallurgical method was cast aluminum slag. Investigations of the phase transitions of the obtained samples were performed by the method of differential scanning calorimetry. It is shown that the temperatures and enthalpies of phase transitions do not differ significantly from the characteristics of standard aluminum (A85). They indicate that the processing of aluminum foundry slag by smelting aluminum production waste together with caustic soda leads to a relatively high purity of aluminum.