Refractories for Cement Industry: Guide

The rotary cement kiln is the most thermally demanding piece of equipment in industrial processing, with a burning zone operating at clinker temperatures of 1350 to 1450°C, gas temperatures that exceed 2000°C in the flame, and a shell that must be kept below 350°C for structural safety. The refractory lining is the material that separates these extremes, and its performance determines the kiln’s availability, thermal efficiency, clinker quality, and maintenance cost. A cement kiln refractory lining represents a significant capital investment, its installation occupies critical maintenance downtime, and its failure forces unscheduled kiln stops that cost the plant production at rates that justify almost any measure that extends lining life. The science of refractories for the cement industry has therefore evolved into a specialized discipline combining ceramic materials science, kiln process chemistry, and installation technology. This article provides a complete technical treatment of refractories for cement plants: the thermal and chemical environment of each kiln zone, the families of refractory materials, monolithic and shaped products, selection criteria, installation methods, drying and heat-up procedures, wear mechanisms, refractory life management, and the maintenance practices that keep linings operating through full campaign life.

The Thermal Environment of the Rotary Kiln

The kiln lining exists in an environment defined by temperature, chemical attack, and mechanical stress, and each of these varies along the kiln length. From the feed end to the discharge end, the material temperature rises from about 100°C to 1450°C, and the gas temperature from about 300°C in the preheater gas to flame temperatures of 1800-2000°C. The lining in each zone must withstand the local temperature with an appropriate margin, must resist the chemical attack of the clinker and gas at that temperature, and must survive the mechanical loads of kiln rotation, shell ovality, and thermal expansion.

The kiln shell acts as the structural backing for the lining, and the lining in turn protects the shell from overheating: the rule of thumb is that the shell temperature must stay below approximately 350°C, because above this the shell steel loses strength and the kiln risks ovality deformation and even shell cracks. The refractory design for each zone is therefore a thermal calculation as well as a material selection: the lining thickness and conductivity determine the heat loss and the shell temperature, and the brick quality determines how long the lining maintains the design. Heat losses through the kiln shell represent 5 to 10 percent of the kiln’s total heat input, so the lining is also an energy management device.

Kiln Zones and Their Lining Requirements

Conventionally, the rotary kiln is divided into zones, each with a characteristic temperature, atmosphere, and lining duty. The definitions vary somewhat between authors, but the standard division for a dry-process preheater kiln is: the feed inlet zone, the calcining zone, the transition zone, the burning zone (also called the sintering zone), and the discharge zone with the nose ring. The preheater tower, the riser duct, the calciner, and the clinker cooler are lined separately with their own refractories, because their duties differ from the kiln itself.

Kiln zones, service conditions, and typical lining materials

Zone	Material temperature	Gas temperature	Main attack	Typical lining
Inlet / feed zone	100 – 500°C	800 – 1100°C	Abrasion, alkali dust, thermal cycling	High-alumina bricks, castables, insulating back-up
Calcining zone	500 – 1000°C	1000 – 1300°C	Alkali and sulfate attack, coating instability	High-alumina 50-70% Al2O3
Transition zone	1000 – 1350°C	1200 – 1600°C	Thermal shock, clinker liquid attack	Magnesia-spinel, magnesia-chrome (if permitted), high-alumina
Burning / sintering zone	1350 – 1450°C	1800 – 2000°C	Clinker liquid penetration, chemical wear, thermal stress	Direct-bonded magnesia-spinel, magnesia-chrome, magnesia-zirconia
Discharge zone	1000 – 1350°C	1200 – 1600°C	Thermal shock, clinker abrasion, flame impingement	Magnesia-spinel, high-alumina with silicon carbide
Nose ring	900 – 1300°C	1400 – 1800°C	Thermal shock, spalling, flame impingement	Steel fiber-reinforced castables, fused cast shapes

Refractory Families: Bricks and Monolithics

Refractories are divided into two product families: shaped refractories, primarily bricks, and unshaped or monolithic refractories, including castables, gunning mixes, and plastics. Bricks dominate the rotary kiln lining, where they are installed in rings and bonded with a thin refractory mortar or with the metal case design that eliminates mortar in the radial direction. Monolithics dominate the preheater, riser, calciner, cooler, and nose ring areas, where the geometry is complex and the installation method, casting or gunning, suits the shape. Within each family, the classification by chemistry determines the service capability: acid refractories based on silica and fireclay, neutral refractories based on alumina and silicon carbide, and basic refractories based on magnesia, which are the materials of the burning zone.

The chemistry classification has a direct process meaning in cement kilns. The clinker is a basic, alkaline material, and at clinker temperature its liquid phase attacks acid and neutral refractories chemically. Basic magnesia-based bricks are chemically compatible with the clinker and actually bond to it through a protective coating that forms on the brick hot face. This is the defining phenomenon of cement kiln lining: a well-run burning zone maintains a stable clinker coating that protects the brick, and the refractory life depends as much on the coating as on the brick chemistry. An unstable coating, caused by unstable chemistry, temperature swings, or fuel variations, exposes the brick to direct attack and shortens its life dramatically.

Burning Zone Refractories: Magnesia-Based Bricks

The burning zone is lined with basic magnesia-based bricks, and the specific grade is chosen by the process conditions. The classic material was magnesia-chrome brick, whose resistance to clinker attack and good coating adherence made it the standard for decades, but the hexavalent chromium formed in service created disposal and occupational health problems, and the industry has largely converted to chromite-free alternatives: magnesia-spinel bricks, which use magnesia-alumina spinel, and magnesia-zirconia bricks, which use zirconia additions for improved flexibility. Magnesia-spinel bricks provide excellent resistance to thermal shock, good coating adherence, and moderate cost, and they are now the dominant burning zone material.

The magnesia brick types are distinguished by their bonding: burned bricks with direct bonding, where the periclase crystals are bonded at high temperature without a silicate matrix, give the highest refractoriness; chemically bonded bricks, where a chemical binder develops the bond in service, give good thermal shock resistance; and unfired or semiburned bricks are used where flexibility is needed. The magnesia content, the spinel content, and the density determine the brick’s performance: higher magnesia increases refractoriness and resistance to clinker liquid, higher spinel improves thermal shock resistance, and higher density reduces penetration. The selection is a balance, and the plant’s choice is documented in the lining specification for each kiln.

Transition and Calcining Zone Refractories

The transition zones, between the burning zone and the calcining zone on one side and the discharge zone on the other, operate at temperatures below full sintering but with severe thermal cycling and frequent coating loss. The materials used are basic bricks in the hot-end transition, typically magnesia-spinel, and high-alumina bricks in the cool-end transition, typically 60-70% Al2O3 grades, sometimes with silicon carbide additions for abrasion resistance where the clinker avalanches against the lining. The transition zones are the zones of coating instability: the clinker coating forms and detaches repeatedly, and the lining experiences thermal shock at every detachment and every kiln restart, which makes thermal shock resistance the governing selection criterion.

The calcining zone, where the material temperature rises through the carbonate decomposition range of 700-900°C, is exposed to abrasion by the rolling feed, to alkali-bearing dust, and to moderately high gas temperatures. High-alumina bricks of 50-70% Al2O3 are the standard, installed with abrasion-resistant castables in the kiln nose and with insulating back-up where the shell temperature demands it. The inlet zone, at the feed end, combines the lowest temperatures with the most abrasive material flow, and the lining there is typically abrasion-resistant high-alumina brick or castable with steel fiber reinforcement, designed primarily for wear life.

Preheater, Precalciner, and Riser Linings

The preheater tower and precalciner are lined with monolithic refractories, because the geometry of cyclones, ducts, and the calciner vessel does not suit standard brick shapes. The duty combines abrasion by the suspended dust and the gas flow, which can reach high velocities in the riser duct and the calciner, with moderate to high temperatures and the chemical condensation of alkalis and sulfates on the cooler walls. The standard materials are low-cement and ultra-low-cement castables of 50-70% Al2O3, selected for abrasion resistance, with the riser duct and calciner typically lined at 60-70% Al2O3 and the cyclones at 50-60% Al2O3 with abrasion-resistant grades in the gas inlet zones and the dip tubes.

Chemical attack in the tower takes two forms. Alkali sulfates and chlorides condense on the cooler surfaces and penetrate the refractory, reacting with the alumina-silicate matrix to form alkali aluminosilicates that cause structural spalling: the surface layer detaches in flakes as the reaction progresses. The second form is the formation of rings and build-ups, where condensed salts cement the dust into hard deposits that restrict gas flow and must be removed mechanically, sometimes at the cost of the lining. The refractory design for the tower therefore balances abrasion resistance, thermal insulation, and resistance to alkali attack, and the installation quality, particularly the anchor system and the joint construction, determines whether the lining survives the campaign.

Clinker Cooler and Nose Ring Linings

The clinker cooler presents an abrasive and thermally cycling duty. Clinker enters the cooler at 1350-1450°C and is cooled to 100°C plus, and the refractory on the cooler roof, walls, and the hottest floor zones must resist the impact and abrasion of the hot clinker bed and the thermal shock of cooler stoppages. The standard materials are low-cement castables reinforced with steel fibers, typically 55-70% Al2O3, with silicon carbide additions in the highest-wear zones, and the roof sections are often bricked in the hottest areas with basic or high-alumina bricks suspended from the structure. The cooler grate areas themselves are metallic, but the side walls and the clinker drop zones require careful refractory design, and lining failures in the cooler are a common cause of unscheduled stops.

The kiln nose ring is the most thermally stressed location in the plant: it is directly exposed to the flame, it sees the full temperature swing of kiln stops, and it is struck by the falling clinker at the discharge. The lining is typically a steel fiber-reinforced low-cement castable, engineered for thermal shock resistance, and installed with an anchor system designed for the geometry. The nose ring life is often the limiting element of the kiln lining campaign, and its inspection and repair are scheduled with the kiln maintenance stops.

Insulating Refractories and Back-up Layers

Refractories also have an energy management function, and the insulating layers behind the working lining are as important as the hot-face materials. The preheater cyclones and ducts, and the kiln shell itself where permitted, are lined with insulating castables and insulating bricks that reduce heat loss and protect the structure. The design rule is a compromise: the working lining must be thick enough for the campaign and the insulating layer thick enough for the heat budget, within the geometric constraints of the equipment. Heat loss through the kiln shell is typically limited by the shell temperature limit of 350°C, and the brick specification is chosen to hold the shell at the target temperature, often with local insulation or with modifications where hot spots develop.

The back-up layer must be compatible with the working lining: its refractoriness must exceed the temperature at its interface, and it must not react with the working brick at that temperature. In basic brick installations, the back-up is often a magnesia-based insulating brick or a castable with compatible chemistry, because a silica-based back-up would react with the magnesia at high temperature. The specification of the complete lining system, working layer plus back-up plus anchor system, is the task of the refractory engineer, and the documentation of the system is part of the kiln’s maintenance record.

Selection Criteria for Kiln Refractories

Refractory selection for each kiln zone is governed by a defined set of criteria, applied in order. The first is the service temperature, with a margin for the peak conditions: the brick’s refractoriness must exceed the maximum temperature it can experience, including the effect of coating loss. The second is chemical compatibility: the lining must resist the clinker liquid, the alkalis, the sulfates, and the chlorides at the service temperature. The third is thermal shock resistance, determined by the temperature cycling the zone experiences through kiln stops and coating loss. The fourth is abrasion resistance, set by the material flow in the zone. The fifth is the mechanical environment: the shell ovality, the kiln diameter, and the brick ring stability. The sixth is the economic balance: brick cost, installation cost, and expected life, expressed as cost per tonne of clinker, which is the metric the plant uses to compare options.

• Temperature: brick refractoriness exceeds peak service temperature with margin for coating loss and flame impingement.
• Chemistry: basic bricks resist clinker liquid; alumina bricks resist alkali attack in the tower and calcining zones.
• Thermal shock: materials are graded for the cycling frequency of each zone, with spinel and fiber-reinforced castables in the most cyclic duties.
• Abrasion: the inlet, riser, and cooler linings use abrasion-resistant grades with silicon carbide where needed.
• Mechanical: brick shapes, thickness, and the kiln shell condition are matched to maintain ring stability under rotation and ovality.
• Economics: the decision is made on cost per tonne of clinker over the campaign, including availability impact.

Installation Methods: Bricklaying and Monolithic Placement

Installation quality determines refractory life more than any other controllable factor, and both major product families have their installation disciplines. Brick linings in the rotary kiln are installed in rings, working from the kiln shell inward. In the modern method, the bricks are placed with the metal case facing the shell and a thin mortar between the radial joints, or with the fully metal-cased brick design that requires no mortar in the radial plane. The rings are driven tight with a special hydraulic or mechanical jack and the ring closure is completed with the cutting of a key brick to close tolerance. The essential quality controls are the ring alignment, the joint thickness, the absence of voids at the shell, and the uniform radial compression, because a brick that is not seated against the shell has no support and fails under rotation.

Monolithic linings are installed by casting, gunning, or a combination. Casting requires formwork, the correct water addition, and vibration to achieve the specified density; gunning applies the mix pneumatically, dry or wet, building the lining in place without formwork; shotcreting, the wet-mix form of gunning, is increasingly preferred for large areas because of its lower rebound and better density. The quality controls are the water content, the layer thickness per pass, the anchor installation, and the curing regime: castables must be cured slowly and then dried before service, because rapid moisture loss during the first heat-up causes steam spalling that destroys the lining. The anchor system, stainless steel anchors welded to the shell and embedded in the castable, is the structural connection between the lining and the vessel, and its density and design are part of the lining specification.

Drying and Heat-up of Refractory Linings

New and repaired refractory linings contain water, both the free moisture of the mix and the chemically bound water of the binder phases, and this water must be removed before the lining meets process heat. The heat-up schedule is a defined rate of temperature rise, typically 20 to 50°C per hour up to the dehydration temperature ranges of 100-150°C and 300-400°C, with holding periods to let the moisture migrate out of the lining thickness. For monolithic linings the schedule is the critical parameter: a castable heated too fast boils its water inside the material, generates steam that cannot escape, and spalls the lining in sheets. The plant’s procedure specifies the heat-up curve, the fuel rates, and the kiln rotation program, and it requires the surface temperature of the shell to be monitored so that the schedule is adjusted to the actual lining condition.

The heat-up of a rotary kiln is conducted on the main burner with a controlled temperature program, often with the kiln turned slowly or stopped periodically to distribute the heat. The completion criterion is the removal of the moisture, verified by the stabilization of the shell temperatures and the gas dew point in the kiln exhaust. The discipline of the heat-up is a major availability factor: kilns that are rushed into service after relining suffer lining failures in the first weeks, while kilns that follow the schedule realize the designed campaign life.

Wear Mechanisms in Cement Kiln Linings

Refractory wear in the cement kiln is the result of several mechanisms acting together, and the diagnosis of the wear mode is the key to correction. Chemical wear is the reaction of the brick with the clinker liquid and the volatile components: the clinker liquid penetrates the brick microstructure, dissolves the brick phases, and the affected layer is carried away with the coating. Thermal shock wear is the cracking and spalling caused by temperature cycling, concentrated in the transition zones and at every kiln stop. Abrasion wear is the mechanical removal by the rolling material, dominant in the inlet, the cooler, and the nose. Mechanical wear is the crushing and loosening caused by shell ovality and ring instability. And infiltration wear is the deposition of alkalis, sulfates, and chlorides within the brick porosity, which changes the brick’s thermal and mechanical properties and causes structural spalling.

Principal refractory wear mechanisms, indicators, and corrective measures

Mechanism	Indicator	Corrective measure
Clinker liquid penetration and dissolution	Thinning brick, glassy hot face, coating loss	Higher-grade basic brick, stable coating, stabilized chemistry and temperature
Thermal shock spalling	Flaking, cracking perpendicular to hot face, debris in kiln	Spinel brick, kiln stop discipline, controlled heat-up and cooling
Alkali/sulfate infiltration	Brick densification, structural spalling, bloating near shell	Lower porosity brick, alkali-resistant matrix, coating maintenance
Abrasion	Uniform wear, smooth polished surface	Abrasion-resistant grades, silicon carbide additions, material flow control
Mechanical damage and ovality	Loosened bricks, mortar loss, shell hot spots	Shell repair and alignment, correct ring tightness, re-bricking
Flame impingement	Local severe wear, exposed shell at one position	Burner adjustment, flame shape control, nose ring reinforcement

The coating is the primary defense against chemical wear in the burning zone, and coating management is therefore refractory management. The coating forms when the clinker liquid contacts the brick at the right temperature, and its stability depends on the clinker chemistry, the temperature stability, and the flame shape. A kiln that operates with stable temperature and a well-formed flame maintains its coating and its lining; a kiln that swings in temperature, fuel, or feed chemistry loses the coating and pays for it in brick wear.

Refractory Life and Kiln Campaign Management

Refractory life is measured in kiln operating days and in tonnes of clinker produced per campaign. Typical burning zone lining lives range from 8 to 18 months on well-run dry-process kilns, with the best installations exceeding two years, while the transition zones, nose ring, and preheater linings have their own lives, which do not necessarily coincide with the burning zone. The plant’s strategy is a life-cycle plan: the linings of the different zones are scheduled so that the kiln relining stops coincide, or so that the zone with the shortest life defines the campaign and the other zones are relined on a rolling schedule that keeps the kiln available for the maximum fraction of the year.

The management tool is the refractory monitoring program: shell temperature scanning, infrared mapping of the kiln shell, and the inspection of the lining during planned stops. Shell scanning detects hot spots that indicate lining thinning, and the trend of the hot spot temperature over time allows the planning of the relining before failure. The brick consumption is tracked per zone, and the data accumulate into the plant’s refractory database, which documents the performance of each material, each installation crew, and each operating regime. The database is the foundation of the continuous improvement of lining life, and it supports the capital decision of when to reline the kiln as a complete campaign versus a sectional repair.

Repairs and Maintenance of Kiln Linings

Between full relines, the lining is maintained through planned and emergency repairs. The planned work is done during the kiln’s scheduled stops, typically every 3 to 6 months for inspection and repair of the zones with the shortest life: nose ring castable, inlet zone brick, transition zones, and the preheater hot spots. The repair methods are sectional re-bricking, where a defined arc or ring is replaced, and gunning repairs, where the worn area is built up with a gunning mix, often with steel fiber reinforcement, restoring the lining profile without a full re-brick. Hot repairs, using gunning mixes that bond to the hot brick, are performed in some plants to extend the campaign to the planned stop, and the hot gunning of the nose ring and the burning zone is a specialized skill.

Emergency repairs are driven by the shell temperature: when a hot spot develops that threatens the shell, the plant must decide between immediate stop and managed operation to the planned stop. The decision is supported by the shell scanning data and the refractory record, and the repair is executed under the stop with the area identified and the cause analyzed. The failure analysis is the essential part of emergency repair: a lining that failed once with a given cause will fail again if the cause is not corrected, whether the cause is operating instability, a burner problem, a chemistry change, or an installation defect.

Quality Control and Refractory Procurement

Refractory performance begins with procurement. The plant’s specification defines the chemical analysis, physical properties, and installation requirements for each lining zone, and the supplier’s products are verified against the specification on delivery: density, porosity, cold crushing strength, and refractoriness under load are the routine checks, and the hot modulus of rupture and thermal shock resistance are checked for the critical grades. The storage and handling of the bricks and mixes are part of the quality system: magnesia bricks hydrate in humid storage, losing strength, and castables absorb moisture from the air, so the materials are stored dry and their age and batch are tracked.

The installation is controlled by the same quality discipline: the kiln shell condition is inspected and repaired before the bricklaying, the rings are checked during installation, the monolithic works are tested for density and thickness, and the heat-up is executed to the documented schedule. The result is documented in the lining report, which records the materials, the installation data, the heat-up curve, and the acceptance tests, and this report becomes the baseline for the campaign’s monitoring. The link between procurement quality, installation quality, and operating discipline is the reason the best refractory performance is found in plants that manage all three as one system.

Specialized Refractories: Unburned, Fused, and Fiber Products

Beyond the standard brick and castable families, the industry uses specialized products for specific duties. Unburned magnesia bricks, which develop their bond during service, are used in the burning and transition zones where their flexibility and thermal shock resistance are beneficial, particularly at kilns with high shell ovality. Fused-cast products, in which the refractory is melted and cast into shapes with a dense crystalline structure, are used in the nose ring and the highest-abrasion cooler zones, where their extreme density and wear resistance justify their high cost. Ceramic fiber blankets and boards are used as insulating back-up layers in the preheater and the cooler, where their low thermal conductivity saves energy and their light weight simplifies the support structure.

Silicon carbide refractories deserve special mention for the cement plant: silicon carbide has the highest thermal conductivity and abrasion resistance of the common refractory materials, and it is used in the form of castables and shapes in the abrasion-critical zones, the cooler impact areas, and the preheater cyclone gas inlets. The cost of silicon carbide is high, so it is used selectively, but its performance in abrasion duty is unmatched. The selection of these specialized products follows the same logic as the standard materials: the failure mode of the zone, the cost per tonne of clinker, and the availability impact of the repair.

Refractory Management and Continuous Improvement

The systematic management of refractories is a defined plant discipline with its own metrics. The primary metric is refractory cost per tonne of clinker, which combines the material cost, the installation cost, and the production impact of lining failures and relining stops. The supporting metrics are the lining life per zone in days, the number of hot spots per campaign, the repair history, and the availability of the kiln. The management system tracks these metrics in the refractory database, reviews them at the plant’s reliability meetings, and uses them to drive improvement: the comparison of materials and installation methods between campaigns, and the benchmarking of the plant’s performance against the industry, identify the opportunities.

The improvement cycle is continuous. Each relining and each failure is analyzed, the cause is classified as material, installation, or operation, and the corrective action is implemented in the next specification, the next installation procedure, or the next operating practice. The interaction between the operating department and the refractory specialist is the engine of the improvement: the operators report the coating behavior and the temperature stability, the specialist interprets the shell scan and the brick condition, and the two agree on the change that will extend the next campaign. Plants that institutionalize this cycle achieve lining lives at the top of the industry range, and their refractory cost per tonne is correspondingly low.

Frequently Asked Questions

What are refractories and why are they critical in cement kilns?

Refractories are materials that withstand high temperature, and in the cement kiln they line the shell to contain the process at clinker temperatures of 1350-1450°C while protecting the steel shell from overheating. Their performance determines kiln availability, heat loss, and maintenance cost.

What is the difference between basic and high-alumina bricks?

Basic bricks, based on magnesia, are chemically compatible with the alkaline clinker and resist its liquid attack, so they line the burning and transition zones. High-alumina bricks, based on alumina, are used where temperature is moderate and abrasion and alkali attack dominate, such as the calcining zone and the preheater.

Why is the clinker coating important for refractory life?

The coating is a layer of clinker liquid that bonds to the brick hot face and protects it from direct chemical attack and thermal shock. A stable coating extends brick life dramatically, while coating instability exposes the brick and accelerates wear. Coating management is the operating key to refractory life.

How long does a kiln refractory lining last?

Burning zone linings on well-run dry-process kilns typically last 8 to 18 months, with the best campaigns exceeding two years. Other zones have different lives, and the campaign is managed by sectional repair so the kiln does not stop for the entire lining at once.

What causes refractory failure?

The main causes are clinker liquid attack when the coating is lost, thermal shock from kiln stops and temperature swings, alkali and sulfate infiltration in the preheater and transition zones, abrasion in the inlet and cooler, and mechanical damage from shell ovality. Most failures are diagnosed by shell scanning and inspection of the worn brick.

Why was magnesia-chrome brick replaced?

Magnesia-chrome brick forms hexavalent chromium in service, which is hazardous to health and complicates disposal. The industry has replaced it with chromite-free magnesia-spinel and magnesia-zirconia bricks that match its performance without the chromium problem.

What is the heat-up schedule and why does it matter?

The heat-up schedule is the controlled temperature rise applied to a new or repaired lining to remove its moisture without spalling. Castables and bricks release water up to 300-400°C, and heating too fast converts the water to steam that blows the lining apart. The schedule is typically 20-50°C per hour with holding periods.

Summary

Refractories are the material foundation of the cement kiln’s operation, and their management is one of the highest-value engineering disciplines in the plant. The kiln presents a spectrum of service conditions, from the abrasion-dominated inlet to the chemically attacked burning zone, and the refractory industry answers with a spectrum of materials: magnesia-spinel and magnesia-zirconia bricks in the burning zone, high-alumina bricks and castables in the calcining and transition zones, fiber-reinforced monolithics in the preheater, cooler, and nose ring, and insulating layers behind them all. The selection criteria are temperature, chemistry, thermal shock, abrasion, mechanics, and economics, applied zone by zone. The installation discipline, bricklaying tolerances, anchor systems, and the drying and heat-up schedule, determines whether the specified performance is realized. And the operating discipline, coating management, temperature stability, shell scanning, and planned sectional repair, determines whether the campaign reaches its design life. The plants that master all three, material selection, installation quality, and operation, achieve the lowest refractory cost per tonne and the highest kiln availability, which is the ultimate measure of refractory performance in the cement industry.

This file is part of the Complete Cement Technical Package (931 files) available from cementequipment.org. Respective rights holders; library copy for the licensed single user.