Highland Refractory supplies MZ-series magnesia refractory bricks for industrial furnace and kiln zones where basic refractory chemistry, high-temperature load stability, and resistance to alkaline slag are important. This page focuses on how to compare MZ-91, MZ-95 and MZ-97 by MgO content, bulk density, apparent porosity, cold crushing strength and refractoriness under load.
Home ›Magnesia Refractory Bricks ›MZ Grade Magnesia Bricks
MZ Magnesia Brick Technical Guide
| 1. Grade overview | MZ-91, MZ-95 & MZ-97 Grade Overview |
| 2. Technical data sheet | MZ Grade Technical Data Sheet |
| 3. Performance factors | How MgO, Density and Porosity Affect Performance |
| 4. Cement kiln | Magnesia Brick for Cement Kilns |
| 5. Steel ladle | Magnesia Brick for Steel Ladles |
| 6. Glass regenerator | Magnesia Brick for Glass Furnace Regenerators |
| 7. Lime kiln | Magnesia Brick for Lime Kilns |
| 8. Product comparison | Magnesia Brick vs Magnesia Carbon Brick |
| 9. Selection checklist | MZ Grade Selection Checklist |
| 10. Purchasing questions | Technical Purchasing FAQ |
The MZ designation is commonly used to identify magnesia refractory brick grades according to their basic refractory chemistry and performance level. In procurement, the grade number should not be viewed as the only selection criterion. MgO content, secondary oxides, bulk density, apparent porosity, CCS, refractoriness under load and the actual furnace atmosphere must be assessed together.
MZ-91 is generally considered when a basic refractory is required for moderate to demanding thermal and chemical conditions, while the project still needs a controlled procurement cost. Confirm MgO, impurity limits and high-temperature load properties on the applicable TDS.
MZ-95 is used when the design requires a higher-purity magnesia grade and tighter control of secondary oxides. It may be evaluated for zones exposed to stronger basic slag or higher thermal load, subject to the furnace design and batch data.
MZ-97 is generally selected for projects that require a high-purity magnesia matrix and stronger resistance to the specified thermal and chemical duty. The final choice must be checked against temperature, slag composition, load and thermal cycling.
Grade names and property ranges can vary by supplier standard. Confirm the applicable MgO, density, porosity, CCS and RUL values against the batch technical data sheet before purchase.
The table below should be completed from Highland’s current technical data sheet for each supplied grade. Do not use a general industry range as a batch guarantee. When a property is not specified for a grade, the quotation or batch TDS should state that the value is available on request.
| Property | MZ-91 | MZ-95 | MZ-97 | Test / Reference |
|---|---|---|---|---|
| MgO (%) | Per batch TDS | Per batch TDS | Per batch TDS | Chemical analysis |
| CaO (%) | Per batch TDS | Per batch TDS | Per batch TDS | Chemical analysis |
| SiO2 / Fe2O3 (%) | Per batch TDS | Per batch TDS | Per batch TDS | Chemical analysis |
| Bulk Density (g/cm3) | Per batch TDS | Per batch TDS | Per batch TDS | Physical test |
| Apparent Porosity (%) | Per batch TDS | Per batch TDS | Per batch TDS | Physical test |
| CCS (MPa) | Per batch TDS | Per batch TDS | Per batch TDS | Physical test |
| RUL / Load Softening Temperature | Per batch TDS | Per batch TDS | Per batch TDS | High-temperature test |
| Permanent Linear Change | Per batch TDS | Per batch TDS | Per batch TDS | Specified test condition |
A batch-specific TDS should identify the grade, test condition, test date or batch reference where applicable. The web page is intended to support initial selection; the agreed purchase specification and batch documentation govern the delivered product.
MgO content is important, but it should not be used alone to judge a magnesia refractory brick. The relationship between chemistry, microstructure and physical properties determines whether a grade is suitable for the selected furnace zone.
Higher MgO purity is generally associated with a more strongly basic refractory matrix, while CaO, SiO2, Fe2O3 and other secondary oxides can influence liquid-phase formation and high-temperature behaviour. The acceptable balance depends on the slag chemistry and atmosphere of the application. A higher grade is not automatically the correct grade if the lining design and service environment do not require it.
Bulk density is commonly considered together with apparent porosity when assessing resistance to slag penetration and mechanical loading. Lower apparent porosity can reduce open pathways for infiltration, while density affects thermal mass and structural response. These properties must be compared using the same test basis rather than numbers taken from different suppliers’ methods.
Cold crushing strength describes resistance to compressive load at room temperature. Refractoriness under load or load-softening temperature provides a different view of behaviour under elevated temperature and mechanical load. Both may be relevant when selecting a brick for a kiln, ladle, regenerator or shaft kiln.
Crystalline phase note: Periclase is generally the primary crystalline phase in magnesia refractory bricks. The exact phase composition should be confirmed by the applicable XRD or technical documentation for the supplied grade.
Cement kiln selection depends on the location inside the kiln rather than on the product name alone. Burning zones, transition zones and cooler-related areas experience different combinations of temperature, coating behaviour, alkali circulation, mechanical load and thermal cycling.
For a cement kiln project, the MZ grade should be reviewed together with the kiln diameter, lining thickness, fuel type, raw meal chemistry, operating temperature, coating stability and the failure pattern of the existing lining. A grade suitable for a protected section may not be appropriate for a high-load or high-erosion zone.
When the project requires a carbon-bonded product for more demanding steel or slag conditions, compare the requirement with the separate Magnesia brick type and bond guide or request a project review.
Steel ladle applications require the lining design to be divided into working layer, safety lining, bottom, sidewall and slag-line areas. Each zone sees a different combination of molten steel contact, basic slag, thermal shock, mechanical impact and repair frequency.
MZ magnesia brick can be evaluated for suitable non-carbon or safety-lining duties when its chemistry and physical properties match the operating conditions. For a slag-line or high-impact area, the comparison should also include MgO-C brick, carbon content, oxidation control and thermal-shock requirements. The correct choice should be based on the steel grade, slag basicity, ladle capacity, lining thickness and campaign target rather than on MgO percentage alone.
For carbon-bonded magnesia products, see the relevant Magnesia refractory brick series and submit the ladle operating information for a product recommendation.
Magnesia bricks may be considered for selected glass furnace regenerator courses where the temperature, alkali vapour exposure, mechanical load and thermal cycling match the grade. Upper and lower checker areas can have different conditions, so the full furnace layout should be reviewed before a single grade is applied throughout.
Magnesia brick should not be presented as a universal replacement for AZS in direct glass-contact zones. Where molten glass corrosion is the dominant failure mechanism, use the dedicated AZS refractory brick selection information and compare the exact furnace position, glass composition and operating temperature.
For regenerator selection, provide the checker geometry, operating cycle, gas atmosphere, temperature profile and any previous corrosion or deformation observations.
Lime shaft kilns and rotary lime kilns expose refractory linings to different mechanical and thermal conditions. Shaft kilns place emphasis on stable geometry and vertical load, while rotary kilns add rotation, abrasion and repeated movement of the burden.
MZ grade selection should consider the kiln type, internal diameter, operating temperature, feed chemistry, dust circulation, lining position and observed damage. If the project involves a partial repair, provide photographs and the dimensions of the damaged zone so the brick shape and grade can be reviewed together.
The final selection remains subject to the supplied batch TDS and the agreed furnace design. Request a technical review before placing a made-to-order brick order.
Magnesia brick and magnesia carbon brick can both appear in basic refractory procurement, but they are not interchangeable products. The bonding system, atmosphere and damage mechanism must be evaluated before a replacement is specified.
| Aspect | Magnesia Brick | Magnesia Carbon Brick |
|---|---|---|
| Primary selection focus | MgO purity, density, porosity and high-temperature load properties | MgO purity, carbon content, antioxidant system and slag compatibility |
| Typical advantage | Basic refractory stability where a non-carbon matrix is preferred | Thermal-shock and slag resistance in demanding metallurgical zones |
| Additional concern | Thermal cycling, slag penetration and mechanical load | Carbon oxidation and the actual furnace atmosphere |
For a manufacturing-route comparison between sintered, fused and unburned magnesia products, visit the Magnesia brick types guide. This page remains focused on MZ grade and performance selection.
Before requesting a quotation, prepare the following information. It allows the supplier to match the grade and physical property requirements to the actual lining duty rather than quoting only by product name.
For a grade recommendation, send the furnace type, lining location, operating temperature, chemical environment, brick dimensions, annual or project quantity and destination port. The technical team can then confirm the applicable MZ grade and the documents required for the order.
The grades represent different performance and chemistry levels within a magnesia refractory brick series. The comparison should include MgO, secondary oxides, density, apparent porosity, CCS and RUL rather than the grade name alone. Confirm the actual values for the supplied batch on the technical data sheet before purchase.
There is no single grade for every cement kiln. Burning zone, transition zone and cooler-related areas experience different temperatures, chemistry, mechanical load and thermal cycling. Provide the kiln zone, feed chemistry, operating temperature and existing lining information for a project-specific review.
MZ magnesia bricks may be evaluated for suitable non-carbon or safety-lining duties, subject to the ladle design and operating conditions. Working layer, bottom, sidewall and slag-line areas may require different materials. Compare the requirement with magnesia carbon brick when thermal shock, impact and slag resistance are dominant concerns.
The terms are often used as related industry descriptions for MgO-based refractory bricks, but the actual product must be identified by its chemistry, bonding route, physical properties and technical data sheet. Confirm MgO content, secondary oxides, density and test conditions before comparing suppliers.
Request the applicable technical data sheet, agreed chemical composition, physical property report, batch or lot reference, dimensional drawing where applicable, packing list and any inspection documents required by the purchase contract. For made-to-order supply, confirm that the quotation and TDS use the same grade and specification.
Send your furnace type, lining location, operating conditions, brick dimensions, quantity and destination port. We will confirm the applicable MZ grade and prepare a project-based quotation.
Minimum Order Quantity: 1 Pallet (1.0 Ton). Made-to-Order per project confirmation. No household retail.
Related Magnesia Resources
Aluminum content 75%-80% Refractory 1770℃ or above
Silicon carbide plates are mainly composed of silicon carbide (SiC) as the aggregate (with a content usually ≥ 80%).
