1. The grade and purity of raw materials: ferro chrome smelting requires the highest possible grade of raw materials Chrome Ore, Coke and Silica. Raw materials with high purity can achieve high yield, high quality and low consumption

2. Harmful impurities: sulfur and phosphorus are the most harmful impurities in raw materials, because after they enter the ferrochrome alloy, they will eventually affect the quality of steel and steel products.

3. The particle size of raw materials: Whether the particle size of raw materials is suitable has a great influence on the smelting process. If the particle size of the raw material is too large, it is not easy to melt, and the reason is difficult, the conductivity increases, the amount of slag increases, the furnace condition deteriorates, and various technical and economic indicators of smelting deteriorate. However, if the particle size of the raw material is too small and there are many powders, the gas permeability of the furnace material will be poor, and the pressure around the electrode will be high, resulting in stinging. Moreover, the powder material is easy to melt, which will cause the upper layer of the furnace to sinter and suspend the material, resulting in material collapse. As a result, the electrode is unstable, the ignition is frequent and the material collapse is frequent, and the unreturned raw material directly enters the crucible, which will also deteriorate the technical and economic indicators. Therefore, there should be strict requirements on the particle size of raw materials for submerged arc furnaces.

∙ Cr2o3 > 40% in chromium ore, Cr2o3/ΣFeO > 2.5, s < 0.05%, P < 0.07%, MgO and Al2o3 content should not be too high; particle size 10-70mm, if it is refractory ore, the particle size should be appropriately smaller.

∙ Coke should contain no less than 84% fixed carbon, less than 15% ash, S<0.6%, particle size 3-20mm.

∙ Silica is required to contain SiO97%, Al2o3 <1. o%, good thermal stability, no soil, particle size 20-80mm.