To identify the process of iron production, some indicators are proposed by using the chemical components of excavated slag. Especially, the ratio of Ti/Fe and V/Fe are useful for this purpose. All indicators, however, are not always appropriate for the distinguishable procedure between bowl-shaped slag and other slag. It is not yet fundamentally explained that major elements of iron-making slag caused from any materials.
In this article, ten major elements which are constituent of iron-making slag as Silicon (Si), Iron (Fe), Aluminium (Al), Titanium (Ti), Manganese (Mn), Magnesium (Mg), Calcium (Ca), Sodium (Na), Potassium (K) and Phosphorus (P) are considered by using the released analytical data. Every element has been normalized against Si, and the correlation diagrams are plotted. The correlation diagram with Si can be distinguished as 3 groups.
( 1 ) Elements Al, Ca, Na, K and P have positive correlation with Si.
( 2 ) Elements Ti, Mn, and Mg do not correlate with Si.
( 3 ) Fe has negative correlation with Si.
Elements of group (1) as Ca, Na, K and P increase the content in any slag during the smelting, refining and forging processes. Thus, it is obvious that these four elements can not be utilized for the distinguishable procedure of ancient iron-making slag.
On the other hand, elements of group (2) as Ti, Mn and Mg are appropriate to be indicators for the distinguishable procedure of two types slag between forging slag (sometimes in refining process) and other slag (normally in smelting process). On the basis of concentration of the 3 elements, it is indicated that bowl-shaped slag is formed in forging (sometimes in refining), and other slag is done in smelting.
As the result of this study, the ratio of element as Mn/Ti, Mn/Si, Mg/Ti and Mg/Si are suggested to be useful as indicators for the distinguishable procedure between bowl-shaped slag and other slag.