Alumina Magnesia Carbon Brick

 

 

Item	Specification
	LMT-75	LMT-70	LMT-65	LMT-60	LMT-55
Al2O3 %	≥75	≥70	≥65	≥60	≥55
Al2O3+MgO %	≥81	≥77	≥80	≥75	≥72
C %	≥5	≥5	≥7	≥7	≥8
Apparent Porosity, %	≤7	≤7	≤7	≤7	≤7
Bulk Density, g/cm3	≥3.2	≥3.15	≥3.1	≥3.0	≥2.9
CCS, MPa	≥60	≥60	≥60	≥50	≥50

 

 

 

Mixing raw materials → forming (machine pressing or vibration molding) → drying → calcining (high temperature carbonization)

 

1. Raw material selection and pretreatment

Core raw materials

Pre-treatment steps

 

Particle Size Optimization: Controlled via ball milling or screening (e.g., "two-stage fine grinding + classification") to ensure densification.

Impurity Removal and Drying: Eliminate iron oxides and dry magnesia sand at 100–150°C to reduce moisture content.

 

2.Formulation design and mixing

Typical ratios (mass fraction)

 

Mixing process

 

Dry Mixing: Aggregate, fine powder, and graphite are dry-mixed for 10–15 minutes to ensure uniform dispersion.

Wet Mixing: Binding agent (resin + solvent) and additives are added and mixed for 20–30 minutes until a homogeneous paste is formed.

 

3. Molding and Curing

 

Molding Methods

Machine Press Molding: For large bricks (≥200 MPa). Pressing speed must be controlled to avoid delamination.

Vibration Molding: Used for shaped or complex components, eliminates air pockets through high-frequency vibration.

Isostatic Pressing: For applications requiring high dimensional accuracy (e.g., electrolytic tank linings).

Curing Conditions

Ambient Curing: Natural hardening at room temperature over 24–48 hours; suitable for small batches.

Heat Curing: Heated to 120–150°C to accelerate resin carbonization. Requires nitrogen protection to prevent oxidation.

 

4. Drying and Firing

Drying Process

Gradual Heating: Temperature raised from 50°C to 200°C to prevent graphite oxidation and cracking.

Humidity Control: Humidity maintained at ≤10%; drying time ranges from 24–72 hours depending on thickness.

Firing Process

Temperature Phases:

Preheating: 200–600°C to remove volatiles.

Carbonization: 600–1000°C to convert resin into a carbon network.

High Temperature: 1400–1600°C to promote Al₂O₃ and MgO reaction, forming spinel.

Protective Atmosphere: Nitrogen or argon is used to prevent graphite oxidation.

 

5. Post-treatment and inspection

Impregnation: High-porosity products are impregnated with resin or asphalt to increase density.

Surface Coating: Applied SiO₂-Al₂O₃ coatings enhance oxidation resistance.

 

 

Core Composition Comparison

 

Alumina-Magnesia-Carbon Bricks: Al₂O₃ (60%–69%) + MgO (7%–14%) + C (5%–12%)

Key Difference: AMC bricks include oxidizing agents to form spinel (MgAl₂O₄), improving performance in certain applications.

 

 

 

Choose Alumina-Magnesia-Carbon Bricks when:

Resistance to both acidic and alkaline slags is needed (e.g., cement kilns)

Long-term operational stability is a priority (e.g., large converters)

Applications require thermal shock and mechanical impact resistance

 

Choose Magnesia-Carbon Bricks when:

Only resistance to alkaline slag is needed (e.g., EAF slag lines)

Lower weight and high thermal conductivity are beneficial (e.g., continuous casting slides)

Cost is a significant consideration

 

 

 

Steel industry:

Converter/EAF Linings: Resists steel and slag erosion.

Ladle Linings: Minimizes secondary oxidation and extends service life.

Continuous Casting Systems: Protects critical parts such as tundishes and slide gates.

 

Cement industry:

Rotary Kiln Firing Zone: Resists clinker melt and alkali vapor attack.

 

Non-ferrous metal smelting:

Aluminum Electrolyzers, Copper Smelters: Custom formulas adjust for specific working conditions.

 

 

Construction sequence

Cast permanent layer for ladle wall

Cast permanent layer for ladle bottom

Place water outlet seat bricks and breathable bricks

Lay AMC bricks for ladle bottom

Fill gaps with corundum cement

Lay AMC bricks for ladle wall and slag line

Install aluminum-magnesium castable at ladle mouth

Cure and bake

 

Wall Masonry Guidelines

Use aluminum-magnesium fire clay. Mortar must not be too thin; joints should be full and less than 1 mm thick.

Bricks should be laid level with staggered joints. Follow the principle of "solid back, tight seams, accurate arc."

Hinge cutting depth should be ≥50 mm, away from the trunnion. Stagger hinges between layers by ≥200 mm.

 

Bottom Masonry Guidelines

Breathable bricks and seat bricks must be positioned flat and accurately.

Fill all surrounding gaps with corundum cement.

 

Casting Construction

Inspect equipment (mixer, water supply, vibrating rods).

Mix dry for 1 minute, then add 2/3 of the water, then the rest. Wet mix for 3–5 minutes.

Vibrate after each pouring step to exhaust air and ensure full compaction.

Maintain continuity during pouring; interruption should not exceed 20 minutes.

 

Repair Procedure

Remove worn seat bricks and old bonding material, then clean thoroughly.

Install new breathable and seat bricks.

Fill gaps with corundum binder.

 

 

 

01/Customized dimensions and shapes

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Customized Brick Shape

Provide Sample Sheets--Mold Opening & Quotation--Mold Opening & Sample Making--Bulk Production Quotation--Contract Signing--Bulk Production

 

02/Delivery cycle and logistics

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Sea freight, land freight. Determine the mode of transportation according to the needs

About 30 days, customized products delivery time depends on the actual situation.

 

03/Customized packaging

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Customize your brand

Logo customization, custom fonts, taglines and messages for packaging, signage, websites or printed materials.

Take your brand to the next level, contact us today to discuss your project!

04/Purchase ZINFON refractory Bricks at Reasonable Prices

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The price of refractory bricks is a known key factor influencing customers' purchasing decisions. Therefore, we offer affordable refractory bricks for sale. Here are several reasons why ZINFON provides refractory bricks at competitive prices:

It is worth noting that while price is an important factor, it should not be the sole determinant of your purchasing decision. When buying refractory bricks from ZINFON, quality, reliability, and technical support are equally important considerations.

 

By choosing ZINFON as your supplier, you can access high-quality refractory bricks, a wide range of other refractory materials, and comprehensive support. Contact ZINFON Refractories immediately to discuss your specific requirements and obtain customized solutions!

 

 

 

 

 

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