High Alumina Refractory Brick for Discharge and Calcining Zones
DISCHARGE ZONE The discharge zone can experience rapid temperatures changes if the kiln is cycled frequently. High strength is favored for resistance to mechanical stresses, especially when bearing the load against the discharge retainer ring
In the calcining zone, the formation of free lime from the decomposition of limestone is completed. Higher alumina refractories are used to resist reaction with the free lime. Alkali attack can occur in other areas of the calcining zone.
ALUMEX P-7 / P-8 - for wear resistance at the kiln discharge · Phosphate-bonded for high mechanical strength and abrasion resistance · Excellent thermal spalling resistance
RESCAL™ 70D - for standard service · Very good alkali resistance · Good strength
ALUMEX P-8 - for service directly above the basic brick · 80% alumina content for increased resistance to reaction with free lime · Improved strength over 70% alumina class brick
RESCAL™ 70D - standard service · Economical · Very good alkali resistance
SENECA™ 60P - for alkali superior resistance · Based on mullite grain for superior resistance to alkali attack · Positive reheat test results for lining stability · Phosphate-bonded with improved strength over 70% brick
Basic Refractory Brick for Cement Kiln Burning Zones
The refractory lining of a burning zone in a modern cement kiln uses several refractory types that correspond to the different process conditions or requirements. Modern cement kilns extensively use magnesite-spinel refractories as the lining materials in the burning zone areas.
LOWER TRANSITION ZONE
The lower transition zone is the basic brick area closest to the kiln discharge. Coating conditions are normally unstable. Refractory wear can occur from thermal stress, the infiltration of clinker liquids and alkali salts, and thermal shock from sudden coating loss.
The burning zone center features a thick and stable coating. Thermal stress can be a factor in refractory wear causing infiltration of the clinker liquids. Alkali salts can deposit in the brick pores.
UPPER TRANSITION ZONE
The upper transition zone normally features a thin, unstable coating, or the coating is completely absent. Refractory wear occurs from the infiltration of alkali salts that weaken the brick structure as well as mechanical stresses from the second kiln support tire.
RESCOMAG® 85 - for standard severe service in the lower transition, excellent thermal spalling resistance
RESCOMAG® 92 FMS - for very severe wear · High content of fused grain for exceptional resistance to clinker liquids
RescoMag 85 - for service in the burning zone center for non-dolomite users and precalciner kilns · For servicing the burning zone for non-dolomite users and calciner kilns
Z-DOL - Standard zirconia enriched dolomite
GREENFREE™ 92 - standard service in the upper transition · Moderate thermal conductivity · Excellent strength to resist shell stresses
RESCOMAG® 85 - for reduced shell temperatures · High spinel content for improved thermal conductivity · Matrix spinel for resistance to alkali salt infiltration
Monolithic Refractories in the Cement Clicker Cooler and Preheater
Monolithic refractories, especially castables and gunning mixes, are widely used in preheater towers and coolers in North America. Advantages of monolithic refractories include ease of application especially for complex geometries, ready availability, improved time for installation and good resistance to infiltration of dust and feed materials.
Most clinker coolers in North America have reciprocating grates. The refractory constructions are above the grates and consist of roof, sidewall and curb linings.
Product selection for the grate cooler includes
Preheater tower maintenance practices favor gunned installation for improved logistics and speed of application except where build-ups form. Cast linings with smooth surfaces help manage build-up formation and removal. 60% alumina low-cement castables and gunning mixes have a great deal of versatility and strong alkali resistance for use in most areas of the preheater, especially in the lower vessels and riser ducts.
In vessels that have lower temperatures, 40% to 50% alumina mixes are preferred. In areas where build-ups form, silicon carbide-containing castables and gunning mixes have been employed for their resistance to wetting by molten alkali salts and subsequent attachment of build-ups
Monolithic Product Descriptions
|EZ Cubed 3000||Cyclone roof and sidewalls, riser linings||Shotcrete application|
|EZ Cubed AZS||Lower riser, feed shelf, precalciner, lowest stage cyclone||Buildup management and shotcrete application|
|Patriot||Cyclone and duct cylindrical sections||Good strength and alkali resistance|
|Progun LC 60 G||Lower preheater gunning maintenance||High strength, moderate alkali resistance|
|QuikLite 3||Back-up lining||Good insulation, installation versatility, reduced dryout time in two-layer constructions|
|QuikTurn AZS PC||Lower riser, feed shelf, precalciner, lowest stage cyclone||Build-up management, reduced curing and dryout, pump/shotcrete application|
|QuikTurn AZS G||Lower riser, feed shelf, precalciner, lowest stage cyclone||Build-up management, reduced curing and dryout, gunite application|
|QuickTurn 60G||Lower preheater gunning maintenance||Reduced curing and dryout, alkali resistance|
|QuikTurn 60PC||Riser Ducts and vessel linings||Reduced curing and dryout, installation versatility, alkali resistance|
|Rescobond 3000G||Cyclone roof and sidewalls, riser ducts||Abrasion resistance, reduced curing and dryout, alkali resistance, bonds to existing refractory|
|Rescocast 15GM||upper vessels, tertiary air duct, meal chutes||Good strength and abrasion resistance, installation versatility, good gunned properties|
|Rescocast 3||Back-up lining||Good insulation and installation versatility|
|Seneca 60P||Precalciner lining, tertiary air duct||Alkali and abrasion resistance|