3.4 Raw Material
3.4.1 Raw material shall be in accordance with the following requirements:
1 The charge grade shall meet requirements for smelting different products,and mixing of earth and dirt is not allowed.
2 The chemical compositions shall be consistent.
3 Pretreatment is required for the raw material for large EAF,and the moisture of main raw materials charged shall be lower than 5%.
4 Carbon reducing agent shall be selected according to EAF capacity and smelting product.
5 Quartz shall be of good thermal stability and perfect anti-explosion property.
3.4.2 The ferrous material shall be in accordance with the following requirements:
1 Steel scrap shall be of carbon material,and it shall be clean.The Fe content shall be higher than 95%,without non-ferrous metal,pig scrap or oil contamination,and the charging length shall be less than 100mm.
2 The TFe content of scale shall not be lower than 65%,and the grain size should be 3mm-5mm.
3 The TFe content of iron ore pellet shall be higher than 65%,and sulfur content shall be lower than 0.01% and grain size should be 8mm-30mm.
3.4.3 Raw materials shall be crushed,screened,dried or sintered and pelletized as pretreatment according to smelting technical conditions,and the raw materials fed to proportioning station shall be qualified ones.
3.4.4 For smelting of refined alloy,the mineral shall be free from carbon material impurity.
3.4.5 The compositions of active lime shall be in accordance with relevant requirements of current industrial standard YB/T 042 Metallurgical lime.
3.4.6 Ore and flux shall be in accordance with requirements specified in Table 3.4.6.
Table 3.4.6 Main technical conditions of ore and flux
3.4.7 The carbon reducing agent shall be as per requirements specified in Table 3.4.7.
Table 3.4.7 Main technical conditions of carbon reducing agent
3.4.8 The storage days of raw materials shall be as per requirements specified in Table 3.4.8.
Table 3.4.8 Storage days(d)of raw materials
Note:Different regions and different raw material sources can be adjusted.
3.4.9 Physical and chemical index of electrode paste shall be as per requirements specified in Table 3.4.9.
Table 3.4.9 Physical and chemical index of electrode paste