Chemical and Physical Properties
Purity Levels:
| Magnesium Chloride | Calcium Chloride |
|---|---|
| Industrial-grade magnesium chloride typically assays at 94-98% MgCl₂ | Deicing-grade calcium chloride is usually 77-80% CaCl₂ (as dihydrate) |
- Higher purity reduces insoluble content that can clog application equipment
Moisture Content:
| Magnesium Chloride | Calcium Chloride |
|---|---|
| Magnesium chloride hexahydrate contains approximately 47% water by weight | Calcium chloride dihydrate contains about 30% water |
- Affects storage stability and application characteristics
Bulk Density:
| Magnesium Chloride | Calcium Chloride |
|---|---|
| 55-65 lbs/ft³ (loose bulk density) | 50-60 lbs/ft³ |
- Important for storage capacity calculations and spreader calibration
Particle Size Distribution:
- Standard grades range from fine powders to 5mm pellets
- Larger particles provide better broadcast spread pattern and slower dissolution
- Smaller particles work faster but may drift in windy conditions
Performance Specifications
Ice Melting Capacity:
- Measured as pounds of ice melted per pound of product at standard conditions
| Magnesium Chloride | Calcium Chloride |
|---|---|
| ~175 lbs ice/lb product at 20°F | ~250 lbs ice/lb product at 20°F |
Freezing Point Depression:
- Saturated solution freezing points:
| Magnesium Chloride | Calcium Chloride |
|---|---|
| -15°F (-26°C) | -25°F (-32°C) |
Viscosity (for Liquid Products):
| Magnesium chloride brine (30%) | Calcium chloride brine (32%) |
|---|---|
| ~15 cP at 20°C | ~10 cP at 20°C |
- Affects spray pattern and equipment selection
Application Parameters
Pre-treatment Brine Concentrations:
| Magnesium Chloride | Calcium Chloride |
|---|---|
| 23-27% by weight for anti-icing | 28-32% by weight |
- Higher concentrations risk crystallization in cold weather
Application Temperature Limits:
| Liquid Magnesium Chloride | Liquid Calcium Chloride |
|---|---|
| Effective to 0°F (-18°C) as pre-treatment | Effective to -10°F (-23°C) |
Coverage Rates:
- See table in the previous section for solid application rates
- Liquid applications typically 30-50 gallons per lane mile for anti-icing
Quality Control Indicators
Impurity Limits:
- Heavy metals (Pb, Cd, As): <10 ppm each for environmental safety
- Insolubles: <0.5% by weight for equipment protection
- Sulfates: <0.1% to prevent concrete interaction
Stability Indicators:
- Caking tendency: Measured by angle of repose (preferably <40 degrees)
- Moisture absorption: Weight gain under controlled humidity
Safety Data:
- Both materials are rated as irritants for skin and eye contact
- Dust control is important during handling to prevent respiratory irritation
Typical Product Specifications for Deicing-Grade Magnesium and Calcium Chloride
| Parameter | Magnesium Chloride Spec | Calcium Chloride Spec | Test Method |
|---|---|---|---|
| Assay (as dihydrate) | ≥94% MgCl₂ | 77-80% CaCl₂ | ASTM E534 |
| Moisture Content | ≤2.0% (anhydrous) | ≤0.5% (anhydrous) | ASTM D4377 |
| Bulk Density (loose) | 55-65 lbs/ft³ | 50-60 lbs/ft³ | ASTM B527 |
| Particle Size (granular) | 90% 1-3 mm | 90% 1-4 mm | ASTM E11 sieves |
| Ice Melting Capacity | ≥175 lbs ice/lb | ≥250 lbs ice/lb | SHRP H-205.8 |
| Freezing Point (saturated) | ≤-15°F (-26°C) | ≤-25°F (-32°C) | ASTM D1177 |
| Heavy Metals (each) | ≤10 ppm | ≤10 ppm | EPA 6010/7471 |