## 1 Introduction  
Aluminum, depending on its content in cast iron, promotes or prevents graphitization. It can act as a graphitizer or stabilizer depending on the quantity in which it is present in cast iron. Therefore, taking into account the widespread presence of aluminum in iron or steel scrap, it is possible to use this contaminated scrap for the production of high-aluminum cast iron [1; 2; 3; 4], which should be used in the construction of machine elements. Fe-CAl alloys, which contain up to 30% mass Al, show two characteristic ranges of graphitization. The first one includes alloys with up to 8 wt. Al, while the second alloys with a content of 18-26 mass % Al. With a content of 9-16 mass % Al and with a content exceeding 26 mass % with Al in cast iron, carbon is found only in the bound form [5; 6; 7; 8]. Figure 1 shows the relation between the aluminum content in cast iron and the form of carbon occurrence [9] and several areas can be defined, including [% mass]:  
Area I-When a small amount of aluminum is introduced into cast iron, in the order of 1.5-2.5%, it shows a ferritic-pearilic structure. A further increase of the aluminum content to 3.6% increases the proportion of ferrite in the matrix. Increasing the aluminum content to 3.6% causes the formation of thick particles of graphite. The addition of aluminum in this area causes, in principle, structural changes analogous to those that occur with the addition of silicon contents;Area II-It corresponds to cast iron with an aluminum content of 3.2-3.8%. The structure is ferritin with the most extensive precipitates of graphite;  
Area IIIa-Eutectoid appears in this range; ferrite + \(\epsilon\). It is a perlite-like structural mixture;  
Area III-In this area (9.7-11.5% AI), there is no longer any graphite. The structure of this area does not change with the increased cooling rate of the castings; Area IIIb-The structure of this area (19.0-23.0% AI) consists of coarse particles of graphite, primary particles of phase \(\epsilon\) and ferrite. As is the case of the structure in area IIIa, the structure of area IIIb changes during the different cooling rates of the alloys. Area IV-In this area (22.7-23.5% AI), similarly to area II, there is a structure containing ferrite and graphite. Area V-This area includes cast iron with a content of 24.0-30.0% AI. and contains: graphite, ferrite, and aluminum carbides; however, with increased aluminum content, the graphite content decreases until it disappears. Cast iron with about 30% AI is a special purpose cast iron. It shows very good resistance to an oxidizing atmosphere at a high temperature, but castings made of this iron tend to break down during operation, as shown in Figure 1.  
In general, high-alumina cast iron is very similar to the well-known materials from the iron aluminides group [10; 11; 12; 13]. Increasing the content of aluminum in cast iron reduces its density and improves resistance to oxidation. For this purpose, a metal charge contaminated with Al can be used [1; 2; 3; 4]. High-aluminum cast iron with higher aluminum content belongs to the group of so-called white cast iron. It turns out that the barrier in the field of application of this material is the concentration of carbon in cast iron and the formation of hygroscopic Al\({}_{4}\)C\({}_{3}\) carbide from aluminum.