The deoxidizing slag is now formed by additions of lime, coke and fluorspar (and for some analyses ferrosilicon). The slag changes from black to white as the metallic oxides are reduced by these deoxidizing additions and the reduced metals return to the bath. A good finishing slag is creamy white, porous and viscous. After the slag becomes white, some time is necessary for the absorption of the sulphur in the bath by the slag.
The white slag disintegrates to a powder when exposed to the atmosphere and has a pronounced odor of acetylene when wet.
Further additions of recarburizing material are added as needed to meet the analysis. The further reactions are shown by the following:
| 3:40 P.M. | —Recarburizing material added: |
| | 130 lb. | ground electrodes. |
| | 25 lb. | ferromanganese. |
| | Analysis: |
| | | Carbon | Silicon | Sulphur | Phosphorus | Manganese | | 0.76 | 0.011 | 0.030 | 0.008 | 0.26 | |
To form white slag there was added:
| 225 lb. | lime. |
| 75 lb. | powdered coke. |
| 55 lb. | fluorspar. |
| 4:50 P.M. | — |
| | Analysis: |
| | | Carbon | Silicon | Sulphur | Phosphorus | Manganese | | 0.75 | 0.014 | 0.012 | 0.008 | 0.28 | |
During the white-slag period the following alloying additions were made:
| 500 lb. | pig iron. |
| 80 lb. | ferrosilicon. |
| 9 lb. | ferromanganese. |
| 146 lb. | 6 per cent carbon ferrochrome. |
The furnace was rotated forward to an inclined position and the charge poured into the ladle, from which in turn it was poured into molds.
| 5:40 P.M. | —Heat poured. |
| | Analysis: |
| | | Carbon | Silicon | Sulphur | Phosphorus | Manganese | | 0.97 | 0.25 | 0.013 | 0.33 | 0.70 | |
| | Ingot weight poured | 94.0 per cent |
| | Scull | 2.7 per cent |
| | Loss | 3.3 per cent |
| Total current consumption for the heat, 4,700 kW.-hr. or 710 kw.-hr. per ton. |