Why can chromite sand be used as drainage sand?
The main reasons include its chemical stability, high hardness and density, good fluidity and permeability, and excellent anti-erosion and sintering properties.
First of all, the main component of chromite sand is chromite, which is rich in Cr2O3, and its content is usually higher than 45%, and can even reach more than 46%. This high chromium content makes chrome ore sand have stable chemical properties, not easy to be oxidized or dissolved, and can remain stable in high temperature and corrosive environments, thereby ensuring the overall performance of drainage sand.
Secondly, the hardness of chromite sand is relatively high, usually between 5.5 and 6.5, and the density is usually between 4.0 and 4.8g/cm³ or 4.5 and 5.0g/cm³. This high hardness and density enable chromium ore sand to effectively resist wear and erosion in drainage sand, while better playing a filling and supporting role. In addition, chrome ore sand has good fluidity, which allows the drainage sand to be quickly and evenly distributed when filling the ladle bottom water inlet, while providing excellent permeability to ensure that the molten steel can flow smoothly during the smelting process. Finally, chromite sand has excellent resistance to erosion by molten steel and can maintain proper sintering performance under high temperature and long-term refining conditions. It will not affect the automatic pouring rate due to excessive sintering, nor will it float up due to insufficient sintering and cause accidents.
Chromite sand for drainage sand, also known as chrome ore sand, is a special sand for foundry with natural chromite ore from South Africa as the main raw material, which is processed into a specified particle size through crushing, screening and other processes. Its main component content Cr2O2 is more than 46%, with high thermal conductivity, resistance to alkaline slag and solid phase sintering characteristics, which can prevent sand from sticking to castings. It is widely used in large steel castings, coating aggregates and chilling material replacement.
Available size:
Sand: AFS30-35 AFS35-40 AFS40-45 AFS45-50 AFS40-50 AFS45-55 AFS50-55 AFS55-60 AFS60-65
Powder: 180MESH, 200MESH, 325MESH, 400MESH, 500MESH, 600MESH, 800MESH, 1000MESH, 1200MESH, 1500MESH, 2000MESH, 2500MESH
Chemcial index for chromite sand:
| Cr2O3 | SiO2 | FeO | CaO | MgO | Al2O3 | P | S | Cr/Fe |
| ≥46.0% | ≤1.0% | ≤26.5% | ≤0.30% | ≤10.0% | ≤15.5% | ≤0.003% | ≤0.003% | 1.55:1 |
Physical index:
| Bulk density | Volume density | colour | PH | sintering temperature | melting point |
| 2.5-3g/cm³ | 4.0～4.8g/cm3 | black | 7-9 | > 1800°C | 2180°C |
