Taphole Clay
Plugs, Rebuilds, and Protects the Blast Furnace Taphole
FerrumX engineers PN1–PN4 taphole clay around its own in-house ferrosilicon nitride (FeSi₃N₄). The result: 30–40% lower erosion, 16–24-hour taphole campaigns, and stable casting for blast furnaces from 100 m³ to 5000 m³.
What It Is · Where It’s Used
A plastic refractory paste that seals the furnace’s single exit
Tap hole clay (also called taphole clay or gun mud) is a plastic refractory material used to plug and rebuild the blast furnace taphole between every cast. It must set rapidly, resist molten iron and slag at 1400–1500 °C, and open cleanly on schedule.
What is tap hole clay?
A composite refractory paste made of alumina, silicon carbide, carbon, and nitride-bonded additives. It is injected by a mud gun to form a mud bag inside the furnace, then drilled open to release iron and slag.
Where is it used?
The taphole is the only controlled exit for molten iron and slag. Clay performance here directly determines cast frequency, iron quality, hearth safety, and furnace productivity.
Performance Matrix
Four PN grades matched to furnace duty
Each grade is tuned to hearth volume, iron throughput, and slag aggressiveness. Higher PN grades deliver higher Al₂O₃, SiC+SiN, and compressive strength for longer campaigns.
| Item / Index | PN4 | PN3 | PN2 | PN1 |
|---|---|---|---|---|
| Applicable Blast Furnace | ≥4000 m³ | 2000–4000 m³ | 1000–2000 m³ | ≤1000 m³ |
| Al₂O₃ (%) | ≥35 | ≥25 | — | — |
| Al₂O₃ + SiO₂ (%) | — | ≥45 | ≥45 | — |
| SiC + SiN (%) | ≥25 | ≥20 | ≥15 | ≥10 |
| C (%) | ≥10 | ≥15 | ≥20 | ≥25 |
| Bulk Density (g/cm³) | ≥2.10 | ≥2.00 | ≥1.85 | ≥1.80 |
| Apparent Porosity (%) | ≤28 | ≤30 | ≤32 | ≤35 |
| Permanent Linear Change (%) | ±1.0 | ±1.0 | ±1.0 | ±1.5 |
| Compressive Strength (MPa) | ≥15 | ≥12 | ≥10 | ≥8 |
| Marshall Value (MPa, 60 °C) | 1.2–1.5 | 0.9–1.2 | 0.6–0.9 | 0.3–0.6 |
Porosity values measured after calcination at 1350 °C × 3 h. Custom formulations available for high-slag, vanadium-titanium, or ultra-long campaigns.
Binder Systems
Water-based, anhydrous, or eco-friendly
FerrumX supplies three binder families so the clay matches your environmental rules, furnace size, and operating practice. Anhydrous clay now dominates the global market with ~81% share because it cures faster and resists erosion better.
H₂O
Water-Based (WB)
Conventional, cost-effective paste for small and medium furnaces. Good workability and easy forming; drying is controlled to avoid steam cracking.
0%
Anhydrous (AN)
The taphole is the only controlled exit for molten iron and slag. Clay performance here directly determines cast frequency, iron quality, hearth safety, and furnace productivity.
ECO
Eco-Friendly (EF)
Low-fume, reduced-PAH, phenol-free binder systems for strict environmental zones. Benzo(a)pyrene kept far below the 50 ppm regulatory threshold.
Vertical Integration
Why FerrumX clay outperforms: in-house FeSi₃N₄
We make the additive that makes the clay
Most taphole clay suppliers buy nitride additives on the open market. FerrumX produces its own ferrosilicon nitride (FeSi₃N₄), giving us control over chemistry, cost, batch consistency, and supply security.
Chemical Composition
$0.79B
Global tap hole clay market in 2026
~81%
Anhydrous share of global taphole clay market
100,000 t
Annual production capability — automatic line
24 h
On-site technical response time
Production Capability
Built for volume, consistency, and global delivery
FerrumX operates a dedicated taphole clay production base with automatic mixing, extrusion, and packaging lines. From raw material inspection to batch CoA, every step is controlled under ISO 9001, ISO 14001, and ISO 45001.
Capacity
100,000 t/yr automatic line
Serving blast furnaces from 100 m³ to 5000 m³, with daily iron output from 2000 to 10000 tons. Product mix covers small-BF, 1080 m³, 2500 m³, >2500 m³, Ti-bearing, and submerged-arc furnace waterless taphole clay.
Equipment
Integrated production chain
LNX-2500 and HN-200 mixing mills, HNPQ-2000 slicing, HNJN-B extrusion, MUD-1350 automatic pressing, XL-2000 automatic batching, organic exhaust treatment, and dust collection systems.
Quality
Complete physical & chemical lab
Re-burning furnaces, high-temperature flexural testers, porosity/density testers, Marshall value testers, 600 kN universal presses, flame photometers, spectrophotometers, analytical balances, XRF analyzers, and rotary viscometers.
Innovation
Patented formulations
Intellectual property covers high-strength erosion-resistant taphole clay, production mixing and extrusion equipment, binder dosing systems, and automatic packaging technology.
Field Performance
Proven in Chinese mega mills and global operations
FerrumX taphole clay is used by major steel groups and refractory contractors across China, Southeast Asia, India, Russia, and the Middle East. FeSi₃N₄-enhanced grades consistently deliver longer campaigns and lower clay consumption.
18 → 6
Taps per day
Longer taphole life reduces the number of daily opening/closing cycles.
1.2 → 0.5
kg clay / t iron
Lower specific consumption cuts both material cost and mud gun workload.
30–40%
Erosion reduction
FeSi₃N₄ forms a dense protective layer against molten iron and slag.
20–25%
Maintenance cost down
Fewer taphole repairs and steadier casting reduce annual maintenance spend.
Steel groups served
Shagang Group, Magang Group, Yonggang Group, Jiangxi Fangda Special Steel, Chongqing Steel, Jiangsu Huiran, Xuzhou Zhongxin Steel, Zhuhai Yuyufeng Steel, and steelmakers in Vietnam, India, Indonesia, Malaysia, and Russia.
Technical partners
Cooperation with leading research institutes including Luoyang Refractory Materials Research Institute, Beijing Iron and Steel Research Institute, Wuhan University of Science and Technology, and Shanghai Institute of Ceramics.
Field Service
Drilling + water-cooled repair — no full shutdown
When hearth temperature rises, or the taphole erodes ahead of schedule, FerrumX supports a proven repair protocol that restores the taphole without taking the furnace offline.
01
Drill & map
Drill the spent taphole to map the eroded profile and size the repair lance to the remaining brick geometry.
02
Water-cooled lance
Insert a water-cooled lance to extract heat. Hearth temperature drops 150–200 °C, stabilising surrounding refractories.
03
Re-plug
Re-inject FeSi₃N₄-enhanced clay to rebuild the taphole geometry and restore clean open/close cycling.
04
Back to cast
The furnace returns to casting within hours, avoiding the millions of dollars in lost production from a full shutdown or reline.
Why FerrumX
A refractory partner, not just a clay supplier
In-house nitride
We produce FeSi₃N₄ ourselves — consistent chemistry, secured supply, and lower additive cost.
✓
Triple certified
ISO 9001 quality, ISO 14001 environmental, and ISO 45001 occupational health & safety systems.
⚙
120,000 t/yr SiC
Vertically integrated silicon carbide capacity backs the SiC component in every refractory we ship.
🌐
Global delivery
Palletized blocks, bulk bags, and multi-modal logistics to steel plants worldwide.
🔬
Technical team
Grade selection, trial support, and on-site taphole management with 24-hour response.
🎯
Custom formulation
Binder, moisture, and additive tuned to your slag chemistry, cast rhythm, and local regulations.
Packaging & Storage
Delivered ready for the casthouse
Packaging is designed for operator ergonomics, batch traceability, and long-distance preservation. Barcode tracking ensures every block is linked to its production batch and CoA.
6 kg wrapped blocks
Plastic-wrapped blocks packed in strong, recyclable cardboard boxes on wooden pallets. Ergonomic stacking and easy forklift access.
Storage conditions
Store at 10–35 °C away from direct sunlight and rain. Minimum shelf life of 6 months under recommended conditions.
Full traceability
Barcode system tracks every batch. Each raw material is inspected before use, and the finished product is tested before release.
FAQ
Frequently Asked Questions
Direct answers to common questions about silicon carbide for refractory applications.
Tap hole clay seals and rebuilds the taphole of a blast furnace between casts. It controls the flow of molten iron and slag, protects the taphole assembly from erosion, and maintains stable furnace operation.
PN1 is for small furnaces up to 1000 m³, PN2 for 1000–2000 m³, PN3 for 2000–4000 m³, and PN4 for mega furnaces ≥4000 m³. Higher PN grades offer higher Al₂O₃, SiC+SiN, and compressive strength.
FerrumX’s in-house ferrosilicon nitride (FeSi₃N₄) bonds the refractory matrix at high temperature, reducing taphole erosion by 30–40%, retaining about 80% of room-temperature strength at 1500 °C, and extending taphole life from 8–12 hours to 16–24 hours.
Water-based clay uses water as a binder and is cost-effective for smaller furnaces. Anhydrous clay uses resin, tar, or pitch binders for ultra-low moisture, higher erosion resistance, and faster curing — ideal for large and mega blast furnaces.
Yes. FerrumX supplies low-fume, reduced-PAH binder systems, including phenol-free and tar-free options, to meet strict environmental regulations while maintaining high taphole performance.
FerrumX tap hole clay serves blast furnaces from 100 m³ mini furnaces up to 5000 m³ mega furnaces, with daily iron output from 2000 to 10000 tons.
Yes. FerrumX supports drilling plus water-cooled lance repair, which lowers hearth temperature by 150–200 °C and restores the taphole without a full furnace shutdown, avoiding millions in downtime cost.
FerrumX tests every batch using re-burning furnaces, high-temperature flexural testers, porosity and density testers, Marshall value testers, universal presses, XRF analyzers, and other physical/chemical instruments. ISO 9001, ISO 14001, and ISO 45001 systems are in place.
Standard packaging is 6 kg plastic-wrapped blocks in recyclable cardboard boxes, palletized for forklift handling. Storage at 10–35 °C away from direct sunlight and rain gives a minimum shelf life of 6 months.
Use the request form on this page. FerrumX provides grade selection, trial lots for qualified buyers, and on-site taphole management support with 24-hour response.
