Industrial Minerals
What it is
Dolomite is a double carbonate of calcium and magnesium. It behaves as a cheaper calcium carbonate with magnesia attached, which is exactly what a glass batch and a steel slag both want, and it works as a white filler wherever the extra hardness is not a problem.
Why buyers specify it
- Supplies both CaO and MgO from one raw material, simplifying a batch.
- Improves chemical durability in glass — the reason it is in almost every container batch.
- Harder than calcite, so it holds up as a filler where abrasion resistance matters.
- Available as lump, chips, granules and powder from the same deposit.
Grades we supply
Grade names are ours; the fineness and the duty are what you match against your current material.
| Grade | Form | Fineness | Usually bought for |
|---|---|---|---|
| XD-Lump | Lump | 20 – 80 mm | Steel making, lime kilns |
| XD-Glass | Granule | 30 – 80 mesh | Container and flat glass batch |
| XD-200 | Powder | 200 mesh | Fillers, agriculture, animal feed |
| XD-400 | Powder | 400 mesh | Paint, plastics, dry-mix mortar |
Other finenesses and surface treatments are available against a firm enquiry. If you are switching from another supplier, send their data sheet and we will match the curve rather than the mesh number.
Typical analysis
Chemistry
| Component | Typical range | Note |
|---|---|---|
| CaO | 30 – 32 % | — |
| MgO | 19 – 21.5 % | The reason to buy dolomite over calcite |
| SiO2 | 0.5 – 2.0 % | — |
| Fe2O3 | 0.1 – 0.5 % | Lower for glass grades |
| Loss on ignition | 45 – 47 % | CO₂ |
Physical properties
| Property | Typical range | Method basis |
|---|---|---|
| ISO brightness | 88 – 95 % | Powder grades |
| Specific gravity | 2.8 – 2.9 | — |
| Mohs hardness | 3.5 – 4 | — |
| Moisture as packed | ≤ 0.5 % | — |
These are typical ranges for dolomite, not a specification. The values that govern your order are the ones measured on your lot and printed on its mill test certificate. Ask for a sample and the certificate that goes with it before you commit a production trial.
Where it is used
Dolomite is not one product sold 4 ways — it is 4 different conversations about the same mineral. We supply it into glass, ceramics & sanitaryware, paint & coatings and detergents & soaps, and in each of those the grade that works is chosen for a different reason: fineness in one, brightness in another, oil absorption or purity in the next.
Each industry below has its own page on this site, written for the people who formulate in it rather than for a general reader. If you work in one of them, start there — it will tell you which dolomite grade we would quote for your application and what we need to know before quoting it.
- Glass — Magnesia source; raises durability and widens the working range.
- Ceramics & Sanitaryware — Flux in wall tile and frit.
- Paint & Coatings — Low-cost white extender.
- Detergents & Soaps — Filler and abrasive.
Packing
| Pack | Detail | Suits |
|---|---|---|
| 25 kg paper or PP bag | Palletised 40 bags per pallet, stretch-wrapped | Powders |
| 50 lb bag | US-standard weight where the plant prefers it | Powders |
| 1,000 kg / 1 MT jumbo bag | Four-loop FIBC with discharge spout | Powders, sand, granules |
| Bulk | Pneumatic tanker or loose in container, where volume justifies it | Sand, granules, lump |
Private-label bags with your own artwork are available from one container. How private label works.
Documents with every shipment
- Mill test certificate for the lot, with the measured values, not the range
- Certificate of analysis signed by the processing plant
- Safety data sheet in the US 16-section GHS format
- Certificate of origin and the commercial invoice and packing list
- Asbestos test report where the mineral and the application call for one
Related minerals
Calcite / Ground Calcium Carbonate
High-brightness GCC. The cheapest way to add volume without losing whiteness.
Talc
Soft, platy magnesium silicate. The workhorse extender in paint, plastics, paper and rubber.
China Clay (Kaolin)
Fine white aluminium silicate. Brightness and coverage in paper, paint and ceramics.
Need a price on dolomite?
Send the grade, the tonnage and the delivery ZIP code. Quote and free sample back within one business day.