Views: 0 Author: Site Editor Publish Time: 2025-04-15 Origin: Site
Coal slag is a byproduct from coal combustion. When coal burns in power plants, leftover ash forms molten slag. It cools, hardens, and becomes a black, glassy material. This is coal slag. It’s sharp, angular, and durable. These traits make it valuable.
Many confuse coal slag with other industrial slags. For instance, copper slag and nickel slag come from metal refining. Unlike them, coal slag has low metal content. It’s safer and more versatile.
Its makeup includes silica, alumina, and iron oxides. Common myths claim it’s hazardous. However, most commercial coal slags meet safety standards.
There are two major types: industrial-grade and roofing-grade.
Industrial-grade coal slag is used in abrasives.
Roofing-grade coal slag goes into roofing shingles as granules.
Grit size matters. You’ll find:
Fine grit (60/90)
Medium grit (30/60)
Coarse grit (16/40)
Coal slag is crushed, screened, and graded. It’s processed using a slag crusher to control shape and size.
Coal slag is a go-to abrasive. Why?
Angular shape cuts fast.
Leaves a clean, etched surface.
Ideal for paint or coating prep.
Industries like shipyards, refineries, and bridges rely on it.
| Property | Coal Slag | Garnet | Sand | Steel Shot |
|---|---|---|---|---|
| Cost | Low | Medium | Low | High |
| Reuse | Single-use | Multiple | Single | Multiple |
| Profile | Deep | Moderate | Light | Varies |
Coal slag’s low cost makes it ideal for single-use jobs. It creates deep surface profiles.
Coal slag is used in asphalt shingles. It adds:
UV protection
Weight
Fire resistance
It’s durable and color-stable. Roofing manufacturers prefer its consistent texture.
Coal slag works as a filler in cement and concrete. It’s lightweight and inert. Engineers use it in:
Pavements
Lightweight concrete
Road base layers
Yes. It’s aggressive and quick-cutting. Ideal for tough coatings, rust, and scale.
Coal slag is cheaper than garnet or steel grit. That’s why it’s widely used in large-scale blasting.
It creates a 2-5 mil profile, depending on grit size. Perfect for epoxy or industrial coatings.
Many brands are free of beryllium and silica. Most products comply with OSHA and EPA standards.
Not usually. It contains small amounts of heavy metals but within safe limits. Use PPE.
Safety Data Sheets (SDS) show it’s non-hazardous. Leading producers follow EPA regulations.
It may have trace amounts. However, modern processing minimizes risk. Tests often show it below OSHA limits.
Dust is the real concern. Use proper ventilation and respirators.
Blast suits
Eye protection
NIOSH-approved respirators
Some facilities reclaim and reuse it. But usually, it’s single-use. It’s affordable enough for disposal after use.
Steel
Concrete
Aluminum (with caution)
Wood (only coarse grit)
Yes. Compatible with most pressure and siphon blasters. Just match the nozzle size.
30/60 grit for general cleaning
20/40 for heavy rust
60/90 for delicate surfaces
Match it with grit size:
| Grit Size | Nozzle Size |
| 16/40 | #7–#8 |
| 30/60 | #6–#7 |
| 60/90 | #5–#6 |
| Property | Value |
| Hardness | 6–7 Mohs |
| Bulk Density | 75–100 lbs/ft³ |
| Specific Gravity | 2.5–2.9 |
| Melting Point | 2200°F |
| Compound | Content (%) |
| Silicon Dioxide | 40–50% |
| Aluminum Oxide | 20–30% |
| Iron Oxide | 10–15% |
| Feature | Coal Slag | Copper Slag |
| Origin | Coal combustion | Copper smelting |
| Color | Black | Dark brown |
| Metal content | Low | Higher |
| Recyclability | Limited | Moderate |
| Surface profile | Deep | Moderate |
| Cost | Low | Medium |
| Use cases | General blasting | Shipbuilding, tanks |
Define your use: Blasting or Roofing?
Check grit size
Match nozzle and pressure range
| Application | Recommended Grit |
| Rust Removal | 20/40 |
| Paint Prep | 30/60 |
| Brick Cleaning | 60/90 |
| Heavy Mill Scale | 16/40 |
Available in:
50 lb bags
1-ton super sacks
Bulk shipments
Coal slag is eco-friendly when used responsibly. It’s inert and non-leaching. Proper disposal is key.
Technically, yes. But it’s cost-effective as single-use.
It can be landfilled or used in construction fill. Always follow local regulations.
Yes, when produced and used under safety standards. Reputable suppliers test and certify their slag.
If you want affordable, fast-cutting abrasives, go with coal slag. It’s perfect for surface prep, roofing, or filler material. Pair it with a slag crusher to manage particle size. It balances price, performance, and compliance.
Ready to try coal slag? Choose the right grade. Match it to your blasting or roofing job. Use PPE. Stay safe. And always work with trusted suppliers.
Want more insights on abrasives? Explore our guides comparing coal slag to other blasting media!
