Chromite sand AFS 40-50 properties and technical Index
Chromite sand AFS 40-50 is a black casting sand with a semi metallic luster. It comes from chrome ore in nature. Chromite sand has a Mohs hardness of 5.5-6.5 and a specific gravity of 4.3-4.8g/cm3. Natural chromite ore is composed of two parts: spinel and gangue, which are usually associated. Spinel is Mg · FeO Al Cr2O3, gangue is serpentinite H4 Fe · Mg3 Si2O9 (hydrated silicon magnesium), and there are also small amounts of magnesium olivine, quartz, green pyroxene and other forms in chromite. The quartz (SiO2) in it is harmful to the chromium ore used in casting and needs to be removed through processing methods.
The technical index of chromite sand AFS 40-50 are as follows:
1. Chemical composition of Chromite sand AFS 40-50
Cr2O3 (chromium trioxide): ≥ 46%
SiO2 (silicon dioxide): ≤ 1.0%
FeO (iron oxide): ≤ 26.5%
Cr: Fe (chromium iron ratio): ≥ 1.5:1
MgO (magnesium oxide): ≤ 10%
CaO (calcium oxide): ≤ 0.3%
Al2O3 (aluminum oxide): ≤ 15.5%
2. Chromite sand AFS 40-50 physical indicators
Mohs hardness: 5.5-6
Melting point: 2180 ℃
Sintering temperature: ＞ 1800 ℃
Specific gravity: 4.0-4.8 g/cm3
Bulk density (LPD): 2.5-3 g/cm3
Color: Black
PH value: 7-9
Thermal conductivity: 0.63 W/M · K
Thermal expansion rate (1000 ℃): 0.6%
Acid consumption value (ADV): ≤ 5ML
Turbidity (JTU): ≤ 110
3. Chromite sand AFS 40-50 Particle size distribution:
| Sieve size | Residue percentage |
| +30mesh(600um) | 1.60% |
| +40mesh(425um) | 22.00% |
| +50mesh(300um) | 34.50% |
| +70mesh(212um) | 32.90% |
| +100mesh(150um) | 9.00% |
| Fineness | AFS 43.47 |
The fineness curve of chromite sand AFS 40-45:
