Introduction
Magnesia-carbon bricks are carbon-composite basic refractory materials manufactured with high-purity magnesia as the main aggregate, graphite as the carbon source, and organic binders such as phenolic resin, through processes including batching, mixing, forming, and heat treatment.
Their main mineral phases are periclase and graphite. Periclase endows the bricks with high-temperature strength and slag corrosion resistance, while graphite provides the material with excellent thermal conductivity and thermal shock resistance.
Magnesia-carbon bricks have wide adaptability. Their formula composition and production processes can be adjusted to meet the requirements of various service conditions, demonstrating strong versatility.
MgO:≥69-85% C:≥5-18% Bulk density:2.87-3.15g/cm
Advantage
Excellent thermal shock resistance: Graphite has a low thermal expansion coefficient and high thermal conductivity. It can effectively relieve thermal stress generated by rapid temperature fluctuations and reduce brick cracking and spalling, making it especially suitable for kiln environments with frequent temperature changes.
Superior slag corrosion resistance: High-purity magnesia provides outstanding resistance to basic slags (such as BOF steelmaking slag and ladle refining slag). The hydrophobic nature of graphite prevents molten slag from penetrating the brick interior. The synergistic effect of these two components greatly enhances corrosion resistance.
Stable high-temperature strength: At temperatures above 1400°C, the carbon-bonded phase provides reinforcement that helps maintain high hot strength, preventing the brick structure from collapsing due to high-temperature softening.
Low creep rate: The bricks exhibit excellent volume stability and a low creep rate at high temperatures. They can maintain the structural integrity of kiln linings over the long term and reduce the risk of steel or slag leakage caused by deformation.
Good oxidation resistance: Antioxidants such as aluminum powder and silicon powder are added to magnesia-carbon bricks. A dense oxide protective layer forms on the brick surface, slowing the oxidative burnout of graphite in high-temperature oxidizing atmospheres and extending the service life of the bricks.
ZINFON Magnesia Carbon Brick
The Application of ZINFON Magnesia Carbon Brick in Ladle Project
Physical and Chemical Specifications - Ladle
| Brand | GMC5 | GMC8 | GMC10 | GMC12 | GMC14 | GMC16 | GMC18 | |
| Index | ||||||||
| MgO(%) | ≥ | 87 | 84 | 82 | 80 | 76 | 74 | 72 |
| C(%) | ≥ | 5 | 8 | 10 | 12 | 14 | 16 | 18 |
| Apparent Porosity(%) | ≤ | 5.0 | 5.0 | 4.0 | 4.0 | 3.0 | 3.0 | 3.0 |
| Bulk Density(g/cm3) | ≥ | 3.10 | 3.08 | 3.02 | 3.00 | 2.97 | 2.95 | 2.93 |
| Cold Crushing Strength(MPa) | ≥ | 45 | 45 | 40 | 40 | 35 | 35 | 35 |
| Hot Modulus Of Rupture1400℃×0.5 | ≥ | 6 | 6 | 8 | 8 | 10 | 10 | 10 |
The displayed indicators are for reference only.
Physical and Chemical Specifications - Converter
| Brand | MC12A | MC14A | MC10A | MC14A | MC16A | MC14A | |
| Index | |||||||
| MgO(%) | ＞ | 83 | 76 | 80 | 78 | 74 | 78 |
| F.C(%) | ＞ | 10 | 14 | 10 | 12 | 16 | 12 |
| Apparent Porosity(%) | ＜ | 4 | 3 | 4 | 4 | 3 | 3 |
| Bulk Density(g/cm3) | ＞ | 3.02 | 2.98 | 3.02 | 3.00 | 2.96 | 3.00 |
| Cold Crushing Strength(MPa) | ＞ | 40 | 35 | 40 | 40 | 35 | 40 |
| Hot Modulus Of Rupture1400℃×0.5 | ＞ | 6 | 12 | 14 | 12 | 10 | 12 |
| Application Position | Furnace bottom | Furnace shaft, molten pool | Impact position | Tapping hole | Trunnion position | Furnace top cap | |
The displayed indicators are for reference only.
Physical and Chemical Specifications
|
Type |
Apparent Porosity % ≤ |
Bulk Density g/cm³ |
Cold Crushing Strength MPa ≥ |
MgO% ≥ |
C% ≥ |
|
MT-5A |
5 |
3.15±0.08 |
50 |
85 |
5 |
|
MT-5B |
6 |
3.10±0.08 |
50 |
84 |
5 |
|
MT-5C |
7 |
3.00±0.08 |
45 |
82 |
5 |
|
MT-8A |
4.5 |
3.12±0.08 |
45 |
82 |
8 |
|
MT-8B |
5 |
3.08±0.08 |
45 |
81 |
8 |
|
MT-8C |
6 |
2.98±0.08 |
40 |
79 |
8 |
|
MT-10A |
4 |
3.10±0.08 |
40 |
80 |
10 |
|
MT-10B |
4.5 |
3.05±0.08 |
40 |
79 |
10 |
|
MT-10C |
5 |
3.00±0.08 |
35 |
77 |
10 |
|
MT-12A |
4 |
3.05±0.08 |
40 |
78 |
12 |
|
MT-12B |
4 |
3.02±0.08 |
35 |
77 |
12 |
|
MT-12C |
4.5 |
3.00±0.08 |
35 |
75 |
12 |
|
MT-14A |
3.5 |
3.03±0.08 |
40 |
76 |
14 |
|
MT-14B |
3.5 |
2.98±0.08 |
35 |
74 |
14 |
|
MT-14C |
4 |
2.95±0.08 |
35 |
75 |
14 |
|
MT-16A |
3.5 |
3.00±0.08 |
35 |
74 |
16 |
|
MT-16B |
3.5 |
2.95±0.08 |
35 |
72 |
16 |
|
MT-16C |
4 |
2.90±0.08 |
30 |
70 |
16 |
|
MT-18A |
3 |
2.97±0.08 |
35 |
72 |
18 |
|
MT-18B |
3.5 |
2.92±0.08 |
30 |
70 |
18 |
|
MT-18C |
4 |
2.87±0.08 |
30 |
69 |
18 |
ZINFON Magnesia Carbon Brick Dimensions
We can customize products according to customer requirements upon receiving your drawings.
| Item | Index | ||
| Permissible dimensional tolerance | Dimension | ＜200 | ±1.0 |
| 201～300 | ±1.5 | ||
| ＞300 | ±2.0 | ||
| Warpage | Length | ≤500 | ≤1.0 |
| ＞500 | ≤1.5 | ||
| Chipped corner (a+b+c) | ≤25 | ||
| Chipped edge (e+f+g) | ≤30 | ||
| Crack width | ≤0.1 | No restriction | |
| ＞0.1 | Not allowed | ||
| Wedge tolerance | ≤1.5 | ||
| Dimensional tolerance in ring height direction for masonry | ±1.0 | ||
| Relative edge difference | ≤1.0 | ||
| Internal layer cracking on cross-section | Not allowed | ||
| *Note: For flat laying, the permissible tolerance of width dimension is ±1.5 mm; for vertical laying, the permissible tolerance of thickness dimension is ±1.5 mm. | |||
process
Applications
Iron and Steel Smelting Industry
Basic Oxygen Furnace (BOF)
Mainly applied in BOF linings, especially in critical zones including the slag line and molten bath area. During BOF smelting, the furnace temperature reaches 1600–1800°C and is accompanied by drastic temperature fluctuations and molten slag erosion. The excellent thermal shock resistance and slag corrosion resistance of magnesia-carbon bricks can significantly extend the service life of BOF linings and reduce the frequency of furnace maintenance.
Electric Arc Furnace (EAF)
Suitable for EAF side walls, furnace bottoms, tapping holes, and other areas. During EAF smelting, furnace linings are subjected to severe erosion from molten steel and slag, as well as intense high-temperature radiation from electric arcs. Magnesia-carbon bricks can effectively withstand these conditions and ensure stable furnace operation.
Ladle Furnace (LF / VD / VOD)
Widely used in the slag line and ladle wall areas of secondary refining ladles. The bricks can withstand severe slag erosion and the high temperatures generated by intensive stirring during the refining process, ensuring stable refining quality and ladle safety.
Steel Ladle
Used in the permanent lining and working lining of steel ladles, particularly in the working lining that comes into direct contact with molten steel and slag. It reduces wear during ladle circulation and improves ladle service life and turnover efficiency.
Non-Ferrous Metal Smelting Industry
Copper Refining Furnace
Installed in the slag line area of pyrometallurgical copper refining furnace linings. It resists corrosion from molten copper and refining slag and adapts well to temperature fluctuations throughout the refining cycle.
Ferronickel Smelting Furnace
Applied in high-temperature sections of furnace linings, where it can resist strong alkaline corrosion and thermal shock caused by ferronickel slag.
Other High-Temperature Kilns
Induction Furnace
Magnesia-carbon bricks are used as lining materials for some large-scale induction melting furnaces to withstand high temperatures and erosion from molten metals.
Kiln Patching & Repair
The bricks can be machined into custom shapes for localized repair of BOFs, steel ladles, and other high-temperature furnaces, enabling rapid restoration of furnace performance.
ZINFON Packaging
Heat-treated fumigated wooden pallets are wrapped with waterproof stretch film and reinforced with edge protectors and strapping belts.
Customized packaging is available according to customer requirements.
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