Dolomite Powder
Dolomite Powder Manufacturer & Bulk Supplier for Industrial and Construction Applications
Sourced from natural dolomite deposits in Chaohu, Anhui, our Dolomite Powder (Calcium Magnesium Carbonate) provides consistent chemical stability, precise particle size distribution, and controlled loss on ignition (LOI). Processed via Raymond mills and air-classification systems, we offer uncalcined fine powders (200-2500 mesh) and calcined dolomite tailored for float glass, photovoltaic solar glass, steelmaking slag conditioning, functional polymer fillers, and construction chemicals. Every production run is tested for elemental purity, particle distribution, and moisture limits to meet international manufacturing standards.
Product Grades & Technical Specifications
Ultra-Low Iron Glass Grade:
Processed specifically for float glass, container glass, and photovoltaic (PV) cover glass. Iron oxide (Fe2O3) is strictly controlled (<= 0.008% / 80 ppm, with premium cuts at <= 50 ppm) to protect optical clarity and light transmittance.
Metallurgical & Refractory Grade:
Supplied in raw ground or calcined powder form (CaO 30-32%, MgO 20-22%). Formulated for fluxing in steelmaking converters/EAFs and for manufacturing basic refractory materials.
Micronized Functional Filler Grade:
Air-classified powders from 800 to 2500 mesh (D50: 2.5-10 um) featuring high brightness (up to 96%). Used as functional extenders in exterior coatings, PVC compounding, elastomeric sealants, and adhesive formulations.
Agricultural & Soil Neutralization Grade:
Coarse ground profiles (200-325 mesh) for adjusting acidic soil pH while supplying bioavailable magnesium and calcium content.
Technical Data Sheet
|
Parameter |
Ultra-Low Iron Grade (Glass) |
Micronized Filler Grade |
Calcined Dolomite Grade |
Test Standard / Method |
|
Calcium Oxide (CaO) |
31.5% +/- 0.5% |
30.5% - 32.0% |
30.0% - 32.0% |
XRF / Complexometric Titration |
|
Magnesium Oxide (MgO) |
>= 20.5% |
>= 20.0% |
20.0% - 22.0% |
XRF / AAS |
|
Iron Oxide (Fe2O3) |
<= 0.008% (80 ppm) [Special: <= 50 ppm] |
<= 0.05% |
<= 0.1% - 0.3% |
ICP-OES / Photometry |
|
Silicon Dioxide (SiO2) |
<= 0.3% |
<= 1.0% |
<= 1.5% |
XRF Analysis |
|
Acid Insoluble Matter |
<= 0.2% |
<= 1.0% |
<= 2.0% |
Gravimetric Method |
|
Whiteness (R457) |
>= 90% |
88% - 96% |
N/A |
ISO 2470 Whiteness Meter |
|
Particle Size (Mesh / D50) |
200 - 400 mesh |
800 - 2500 mesh (D50: 2.5-10 um) |
200 - 325 mesh |
Laser Diffraction (ISO 13320) |
|
Moisture Content |
<= 0.2% |
<= 0.3% |
<= 1.0% |
Direct Heating (105 deg C) |
|
Loss on Ignition (LOI) |
45.0% - 47.0% |
45.0% - 47.0% |
<= 2.0% |
Muffle Furnace (1000 deg C) |
Industrial Applications
Glass & Photovoltaic (PV) Solar Module Manufacturing
Dolomite acts as a stable source of MgO and CaO in glass batch recipes. The inclusion of MgO acts as a structural network modifier, improving glass chemical durability, lowering thermal expansion coefficients, and inhibiting devitrification during continuous pulling. Low-iron grades prevent greenish tinting in float glass and maximize solar transmittance in PV glass modules.
Paints, Exterior Coatings & Polymer Compounding
Utilized as a structural extender pigment. The sub-angular crystalline morphology of dolomite powder controls oil absorption, increases mechanical scrub resistance, and enhances weathering performance in exterior architectural paints, epoxy floorings, and rigid PVC profiles.
Metallurgical Slag Conditioning & Refractories
In BOF (Basic Oxygen Furnace) and EAF (Electric Arc Furnace) steelmaking, calcined dolomite powder accelerates slag formation, adjusts slag viscosity, and maintains critical MgO saturation levels. This chemical equilibrium helps reduce furnace lining wear on magnesium-carbon refractories.
Construction Chemicals & Tile Adhesives
Serves as a chemically inert structural filler in ceramic tile mortars, joint fillers, and elastomeric sealants, contributing to controlled drying rheology and minimized volumetric shrinkage.
Quality Control & Lot Traceability
Geological Mining & Optical Sorting:
Ore is extracted from selected quarry faces with stable MgO baselines. Automated color and optical sorters reject non-conforming gangue minerals prior to primary jaw crushing.
Inline XRF & Spectrophotometric Testing:
Real-time X-ray Fluorescence (XRF) monitoring checks CaO, MgO, and Fe2O3 concentrations during grinding operations.
Granulometry Control:
Malvern Mastersizer laser diffraction units analyze sample batches to maintain top-cut (D97) and median diameter (D50) conformity.
Batch COA Issuance:
Every outgoing shipment is accompanied by a Certificate of Analysis (COA) documenting chemical composition, sieve retention, moisture percentage, and whiteness index.
Customization Options: Grinds & Packaging
Particle Size Profiles
Multi-stage air classifiers allow customized particle size distributions based on technical requirements:
Coarse / Granular Grades: 20 mesh to 100 mesh
Standard Industrial Powders: 200 mesh, 325 mesh, 400 mesh
Micronized / Ultrafine Powders: 800 mesh, 1250 mesh, 2000 mesh, 2500 mesh
Export Packaging Options
25 kg / 50 kg Valve & Woven Bags: Polypropylene (PP) outer bags integrated with inner Polyethylene (PE) liner films to manage ambient moisture ingress.
1.0 MT / 1.25 MT Flexible Intermediate Bulk Containers (FIBC): Heavy-duty bulk bags equipped with top fill spouts and bottom discharge chutes, rated for industrial forklift and crane logistics.
Palletization: Goods are stacked on ISPM-15 compliant fumigated wooden or plastic pallets, secured with heavy-duty strapping and shrink-wrapped for transit protection.
Operating near Chaohu, Anhui, our processing plant connects directly to Yangtze River waterways and regional deep-sea export terminals (Shanghai and Ningbo).
Monthly Supply Capacity:
Up to 300,000 Metric Tons across ground and calcined lines.
Standard Production Lead Time:
3-5 working days for standard industrial mesh sizes; 7-10 days for customized low-iron or micronized grinds.
Minimum Order Quantity (MOQ):
20 Metric Tons (1 x 20' FCL).
Export Compliance Documentation:
Shipments include COA, Safety Data Sheet (SDS/MSDS), Commercial Invoice, Packing List, Bill of Lading, and Certificate of Origin (e.g., Form E, CO). Lab sample quantities (up to 5 kg) are available upon request for qualification testing.
Our Certificate
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Q: How does Dolomite Powder differ chemically and physically from Ground Calcium Carbonate (GCC)?
A: Dolomite Powder is a double carbonate mineral (CaMg(CO3)2) containing roughly 30-32% CaO and 20-22% MgO, whereas GCC (CaCO3) contains minimal magnesium oxide. Dolomite offers higher Mohs hardness (3.5-4.0 vs. 3.0 for calcite), greater acid resistance, and provides essential MgO fluxing properties required in glassmaking and steel slag control.
Q: What quality controls ensure Fe2O3 levels stay below 0.008% for solar/optical glass?
A: Raw rock is selectively mined from specific low-iron quarry veins. Processing includes high-intensity magnetic separation stages to capture micro-iron particles before final fine milling. Each production lot is verified via ICP-OES to confirm compliance with Fe2O3 <= 0.008% (80 ppm) specifications.
Q: How is moisture controlled for long-distance maritime export?
A: Dolomite powder passes through thermal drying circuits prior to bagging, reducing moisture content below 0.3%. Packaging features heavy-duty PP woven bags or FIBCs fitted with polyethylene (PE) inner liners, combined with full pallet stretch-wrapping to resist moisture penetration during sea transport.
Q: Can specific particle size distributions (D50 / D97) be customized?
A: Yes. By adjusting classifier wheel speeds and airflow parameters, we produce tailored particle size curves to meet targeted D50, D97, or top-cut specifications required by sealant, paint, and masterbatch formulators.
Q: What is the REACH status of this product for export to European Union markets?
A: Dolomite is a naturally occurring, non-chemically modified mineral (CAS No. 16389-88-1 / EINECS No. 240-440-2). Under Annex V of EU REACH regulations, naturally mined minerals that are not chemically altered are exempt from mandatory REACH registration. Official REACH exemption statements and SDS documents are provided upon request.
Q: What is the process for requesting lab evaluation samples?
A: Complimentary sample lots (up to 5 kg) are supplied for lab verification and trial processing. Sample shipments include a batch-specific Certificate of Analysis (COA). Courier shipping charges are arranged via customer carrier accounts or invoiced prior to dispatch.