The purpose of this work was to re-assess the metal forming reactions taking place in the electric arc furnace during ferro silicon production. The different phases and reaction zones close to, or nearby the crater walls formed by the electric arc, were of special interest in this thesis. Samples were deeper investigated with Light Optical Microscope (LOM), Electron Probe Micro Analysis (EPMA) and X-Ray Diffraction (XRD) for establishing the different phases present in mentioned areas. The crater walls have three phases presents as the most, a carbide-silicon phase where á-SiC is the most common, a ferro-silicon phase where Fe3Si is found through the entire wall and at some areas a silicon phase. There is a slag phase present at the lower parts of the crater wall where the material is denser at two points in a macro point of view. The slag phase can be found in veins surrounding the carbide phases , nitrogen exists in this oxide phase. Iron ore is disintegrated into small droplets at the surface of the furnace and reduced.