BASIC REFRACTORIES

Basic Refractory Bricks

ASTM C455 certified basic refractory bricks with 85-98% MgO content engineered for superior resistance to basic slags in steelmaking, cement production, and non-ferrous metallurgy applications operating at temperatures up to 1850°C.

Temperature Rating 1600-1850°C
Standard ASTM C455/C456
MgO Content 85-98%
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Basic Refractory Bricks for Steel Industry

Product Overview

Basic refractory bricks are alkaline oxide-based materials characterized by high magnesia (MgO) and/or calcia (CaO) content, engineered to resist corrosive attack from basic slags containing high concentrations of CaO, MgO, and FeO encountered in steelmaking and cement production. The term "basic" refers to their chemical basicity (pH >7), contrasting with acidic refractories rich in silica and alumina.

Our basic refractory portfolio includes magnesia bricks (85-98% MgO), magnesia-chrome bricks (MgO-Cr₂O₃ combinations), dolomite bricks (MgO-CaO), and magnesia-alumina spinel bricks (MgO-Al₂O₃). Each composition is optimized for specific slag chemistries, thermal cycling conditions, and mechanical loads. Manufacturing employs high-purity raw materials including fused magnesia, electro-fused magnesia, and seawater magnesia, processed through isostatic pressing or direct-bonding techniques to achieve superior density and direct periclase-periclase bonding.

Compliance with international standards including ASTM C455 (magnesia bricks), ASTM C456 (magnesia-chrome bricks), ISO 10081, and JIS R2213 ensures consistent quality. Every batch undergoes rigorous testing for MgO and Cr₂O₃ content, bulk density, apparent porosity, cold crushing strength, and refractoriness under load. Our manufacturing partners employ advanced bonding technologies including direct-bonded (DB), rebonded-fused grain, and co-clinker processes. Complete mill test certificates and technical documentation accompany all shipments.

Key Benefits

Superior Basic Slag Resistance

Exceptional resistance to CaO-MgO-FeO slags in BOF/EAF steelmaking

High-Temperature Performance

Operating capability up to 1850°C with RUL values 1600-1700°C

Thermal Shock Resistance

Mag-chrome grades withstand BOF/EAF thermal cycling and thermal shock

Direct-Bonded Technology

Superior periclase-periclase bonds for enhanced strength and corrosion resistance

Quick Specifications
  • Max Temperature: 1600-1850°C
  • MgO Content: 85-98%
  • Bulk Density: 2.9-3.3 g/cm³
  • Porosity: 12-20%
  • Crushing Strength: 40-80 MPa
  • Primary Use: Steel, Cement, Non-ferrous
PRODUCT TYPES

Basic Refractory Brick Types

Comprehensive range of basic refractories optimized for different slag chemistries and operating conditions

Basic Refractory Bricks Product Range
Core Product

Magnesia Bricks

Pure magnesia bricks with 85-98% MgO content. Excellent basic slag resistance for steelmaking and cement production. Available in rebonded and direct-bonded grades.

  • MgO: 85-98%, CaO: <2.5%
  • Temperature: 1650-1800°C
  • Bulk Density: 2.9-3.1 g/cm³
  • Applications: BOF/EAF linings, cement kilns
Premium

Magnesia-Chrome Bricks

MgO-Cr₂O₃ composite offering superior thermal shock resistance and corrosion resistance. Optimal for BOF converters experiencing severe thermal cycling.

  • MgO: 50-80%, Cr₂O₃: 8-30%
  • Temperature: 1700-1850°C
  • Bulk Density: 3.0-3.3 g/cm³
  • Applications: BOF slag lines, EAF hot spots

Chrome-Magnesia Bricks

Cr₂O₃-dominant composition with lower MgO content. Enhanced resistance to ferrous oxide penetration. Specialized for copper smelting and specific steel applications.

  • Cr₂O₃: 30-50%, MgO: 30-50%
  • Temperature: 1650-1800°C
  • Bulk Density: 3.1-3.4 g/cm³
  • Applications: Copper converters, RH degassers

Dolomite Bricks

MgO-CaO based refractories from dolomite (CaMg(CO₃)₂). Excellent for basic slag zones but requires careful storage due to CaO hydration susceptibility.

  • MgO: 35-45%, CaO: 40-55%
  • Temperature: 1600-1750°C
  • Bulk Density: 2.8-3.0 g/cm³
  • Applications: BOF converters, steel ladles

Magnesia-Alumina Spinel

MgO with MgAl₂O₄ spinel phase providing excellent thermal shock resistance and slag corrosion resistance. Increasingly popular for steel ladles and tundishes.

  • MgO: 70-90%, Al₂O₃: 5-15%
  • Temperature: 1650-1800°C
  • Bulk Density: 2.9-3.1 g/cm³
  • Applications: Steel ladles, tundishes, RH snorkels
High Performance

Direct-Bonded Magnesia (DBM)

Advanced technology with direct periclase-periclase bonding through high-temperature sintering. Superior strength and slag resistance for critical applications.

  • MgO: 95-98%, direct bonding
  • Temperature: 1700-1850°C
  • Bulk Density: 3.0-3.2 g/cm³
  • Applications: BOF slag zones, high-wear areas
TECHNICAL DATA

Detailed Technical Specifications

Comprehensive specifications for basic refractory bricks

Property Unit Magnesia Mag-Chrome Chrome-Mag Dolomite DBM
MgO Content % 85-98 60-80 30-50 35-45 95-98
Cr₂O₃ Content % ≤1.0 8-30 30-50 ≤0.5 ≤1.0
CaO Content % ≤2.5 ≤2.0 ≤5.0 40-55 ≤1.5
Refractoriness Under Load °C 1550-1650 1600-1700 1580-1650 1500-1600 1650-1700
Maximum Service Temp °C 1650-1800 1700-1850 1650-1800 1600-1750 1750-1850
Bulk Density g/cm³ 2.9-3.1 3.0-3.3 3.1-3.4 2.8-3.0 3.0-3.2
Apparent Porosity % 16-20 14-18 15-19 18-22 12-16
Cold Crushing Strength MPa 40-60 50-70 50-70 35-50 60-80
Thermal Expansion (1000°C) % 1.3-1.5 1.2-1.4 1.1-1.3 1.4-1.6 1.3-1.5
Standards: ASTM C455 (magnesia), ASTM C456 (mag-chrome), ISO 10081, JIS R2213. Testing per ASTM C20, C133, C16.
Storage Note: Magnesia and dolomite bricks susceptible to hydration. Store in dry conditions (<60% RH), use moisture barrier packaging.
APPLICATIONS

Industries & Applications

Basic refractories serve critical applications in steel, cement, and non-ferrous metallurgy

Steel & Metallurgy

BOF/EAF converters, steel ladles, tundishes, torpedo ladles, AOD/VOD converters, RH degassers, EAF sidewalls and bottoms.

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Cement & Lime

Cement rotary kiln burning zones, transition zones, lime kilns, coating layers, high-alkalinity environments.

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Non-Ferrous Metallurgy

Copper converters, lead blast furnaces, nickel smelters, flash smelting furnaces, reverberatory furnaces.

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Chemical Processing

Phosphorus furnaces, calcium carbide furnaces, high-temperature chemical reactors operating in basic environments.

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Specific Applications

Steelmaking Applications:

  • BOF converter slag zones (mag-chrome DBM)
  • EAF sidewalls and bottoms (magnesia, mag-chrome)
  • Steel ladle slag lines (mag-spinel, magnesia)
  • Tundish working linings (mag-spinel)
  • AOD/VOD converter linings (mag-chrome)
  • RH degasser snorkels and vessels (mag-spinel)

Other Industry Applications:

  • Cement kiln burning zones (magnesia)
  • Cement kiln transition zones (mag-spinel)
  • Copper converters (chrome-magnesia)
  • Lead blast furnace hearths (magnesia)
  • Lime kilns (dolomite, magnesia)
  • Phosphorus electric furnaces (magnesia)
WHY CHOOSE US

Key Features & Advantages

Superior Basic Slag Resistance

Engineered for CaO-MgO-FeO slags with C/S ratios >2.0 common in BOF/EAF steelmaking. MgO-based chemistry resists corrosive dissolution by basic slags through thermodynamic compatibility. Direct-bonded periclase grains minimize secondary phases susceptible to slag penetration. Achieves 2-3x longer service life than acidic refractories in basic environments.

Thermal Shock Resistance

Magnesia-chrome combinations provide exceptional thermal shock resistance critical for BOF/EAF thermal cycling (scrap charging, tapping cycles). Cr₂O₃ addition creates microcracks that accommodate thermal stress, reducing catastrophic failure. Withstands temperature swings of 500-800°C during tapping and charging operations. Mag-spinel grades offer balanced thermal shock and slag resistance.

Direct-Bonded Technology

Advanced direct-bonded manufacturing creates strong periclase-periclase bonds through high-temperature sintering at 1700-1800°C, eliminating weak silicate bonding phases. Superior mechanical strength (60-80 MPa vs 40-60 MPa for rebonded), better RUL (1650-1700°C vs 1550-1650°C), enhanced slag corrosion resistance. Optimal for critical zones: BOF slag lines, EAF hot spots.

High-Temperature Performance

Operating capability up to 1850°C for magnesia-chrome grades. High melting point of MgO (2800°C) ensures stability at steelmaking temperatures. Refractoriness under load values 1600-1700°C maintain dimensional stability under combined thermal and mechanical loads. Minimal creep at operating temperatures preserves lining geometry and prevents premature failure.

International Standards Compliance

Full compliance with ASTM C455 (magnesia bricks), ASTM C456 (magnesia-chrome bricks), ISO 10081, and JIS R2213 standards. ISO 9001:2015 certified manufacturing. Comprehensive testing per ASTM C20 (porosity/density), ASTM C133 (crushing strength), ASTM C16 (RUL), ASTM C1171 (chemical analysis). Mill test certificates, TDS, MSDS provided. SGS/Bureau Veritas inspection available.

Global Export Excellence

Serving steel and cement industries in 30+ countries. Expert packaging with moisture-barrier wrapping protecting against hydration during shipping. Wooden pallets, steel strapping, container stuffing expertise. Complete export documentation. FOB, CFR, CIF terms. 4-6 week lead times. Technical support for lining design, installation practices, heat-up schedules. Application engineering assistance.

FAQ

Frequently Asked Questions

Common questions about basic refractory bricks

Basic refractory bricks are materials with high alkaline oxide content, primarily magnesia (MgO) and/or calcia (CaO), engineered to resist corrosive attack from basic slags containing high concentrations of CaO, MgO, and FeO encountered in steelmaking processes. They're called "basic" due to their chemical basicity (pH >7 when hydrated), contrasting with acidic refractories rich in silica (SiO₂) and alumina (Al₂O₃). Main types include: magnesia bricks (85-98% MgO) for general basic environments, magnesia-chrome bricks (MgO-Cr₂O₃) for superior thermal shock resistance in BOF/EAF converters, dolomite bricks (MgO-CaO) for specialized applications, and magnesia-alumina spinel bricks (MgO-MgAl₂O₄) combining basic slag resistance with thermal shock resistance. The basic chemistry ensures thermodynamic compatibility with basic slags, preventing dissolution and extending service life.

Magnesia bricks contain 85-98% MgO with minimal other oxides, offering excellent basic slag resistance but moderate thermal shock resistance (thermal expansion coefficient ~1.4%). Magnesia-chrome bricks combine 50-80% MgO with 8-30% Cr₂O₃, providing significantly superior thermal shock resistance critical for BOF/EAF thermal cycling during scrap charging and tapping operations. Chrome addition creates beneficial microcracks that accommodate thermal stress, reducing catastrophic spalling. Additionally, mag-chrome bricks offer improved corrosion resistance against ferrous oxide (FeO) penetration, better mechanical strength at high temperatures (crushing strength 50-70 MPa vs 40-60 MPa), and reduced hydration susceptibility. Cost differential: mag-chrome bricks cost 1.5-2x more than straight magnesia but deliver 1.5-2x longer service life in severe BOF/EAF conditions, providing better total cost of ownership in critical applications.

BOF (Basic Oxygen Furnace) converters are the primary user, employing magnesia-chrome direct-bonded bricks in slag lines and impact zones experiencing CaO-rich slag (C/S ratio 3-4) and extreme thermal shock from oxygen lancing. EAF (Electric Arc Furnace) sidewalls and bottoms utilize magnesia or magnesia-chrome bricks for basic slag resistance and thermal cycling. Steel ladles employ magnesia or magnesia-alumina spinel bricks in slag zones above metal line. Tundishes for continuous casting use magnesia-spinel or magnesia-chrome linings. AOD (Argon Oxygen Decarburization) and VOD (Vacuum Oxygen Decarburization) converters for stainless steel production rely on mag-chrome bricks. RH (Ruhrstahl-Heraeus) degassers utilize magnesia or mag-spinel refractories in snorkels and vessel linings. Each application selects specific compositions based on slag basicity (C/S ratio), operating temperature, thermal cycling frequency, and mechanical erosion from metal flow. Cement rotary kilns also extensively use magnesia bricks in high-alkalinity burning zones.

Magnesia (MgO) readily reacts with atmospheric moisture forming magnesium hydroxide (Mg(OH)₂) through the reaction: MgO + H₂O → Mg(OH)₂. This hydration causes volume expansion up to 120%, generating internal stresses leading to strength loss, cracking, and complete structural failure. CaO in dolomite bricks hydrates even more aggressively: CaO + H₂O → Ca(OH)₂ with 98% volume increase. Prevention methods: (1) Store in dry, covered warehouses maintaining <60% relative humidity; (2) Use moisture-barrier wrapping (polyethylene, wax-impregnated paper) for long-term storage; (3) Minimize storage time between manufacturing and installation (ideally <6 months); (4) Apply hydration-resistant coatings or impregnations; (5) Chrome oxide addition inherently reduces hydration susceptibility; (6) Tarred or pitch-impregnated bricks provide moisture barriers; (7) Rapid installation after unpacking; (8) Preheat at 200-400°C to remove surface-absorbed moisture before high-temperature service. Hydrated bricks must be discarded as reheating cannot reverse structural damage.

The CaO/SiO₂ ratio (C/S ratio or basicity index) quantifies slag chemistry: ratios >1.0 indicate basic slags, <1.0 indicate acidic slags. Basic refractories require slags with C/S ratios >2.0 for optimal performance. In steelmaking, BOF slags typically have C/S ratios of 2.5-4.0, necessitating magnesia-based linings. EAF slags range from 1.5-2.5 depending on scrap chemistry. Higher C/S ratios mean more aggressive basic slag attack on acidic refractories (fireclay, high-alumina) through formation of low-melting calcium-aluminum-silicates, but minimal attack on magnesia-based basic bricks due to thermodynamic compatibility. The fundamental principle: match refractory chemistry to slag chemistry. Basic slags (high CaO/MgO) require basic refractories (magnesia, mag-chrome). Acidic slags (high SiO₂/Al₂O₃) require acidic refractories (fireclay, high-alumina, silica). Mismatches cause rapid corrosion through chemical dissolution reactions. C/S ratio monitoring guides refractory selection: ratios >2.5 mandate magnesia-based linings, 1.5-2.5 may use mag-spinel or high-alumina, <1.5 suit high-alumina or fireclay bricks.

Direct-bonded (DB) magnesia bricks employ high-purity magnesia grains that bond directly through solid-state sintering at 1700-1800°C, creating strong periclase-to-periclase bonds with minimal or no secondary silicate phases. This advanced technology produces superior mechanical strength (60-80 MPa vs 40-60 MPa for rebonded), better slag penetration resistance (no weak silicate phases for slag to attack), higher refractoriness under load (1650-1700°C vs 1550-1650°C), and significantly longer service life. Rebonded bricks use pre-fired magnesia clinker as aggregate with fresh magnesia powder as bonding matrix, fired at lower temperatures (1550-1650°C). While adequate for moderate conditions, rebonded bricks contain more secondary phases (silicates) susceptible to slag attack. Direct-bonded bricks cost 1.3-1.5x more but recommended for critical zones: BOF converter slag lines, EAF hot spots, high-wear areas experiencing severe slag corrosion. Rebonded bricks suit less demanding areas: ladle sidewalls below slag line, backup zones, areas with lower slag contact. Selection depends on balancing initial cost against expected service life and replacement costs.

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Need Basic Refractories for Steel or Cement Production?

Get expert consultation on magnesia, magnesia-chrome, and dolomite brick selection. Our refractory engineers analyze your slag chemistry, thermal cycling, and operating conditions to recommend optimal solutions for maximum campaign life.

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