Refractory bricks are widely used in the linings of high-temperature furnaces, kilns and industrial heating equipment. After long-term exposure to high temperatures, thermal shock and mechanical wear, refractory bricks may crack, spall or become severely damaged. The damaged lining must then be removed before repair or relining.1. Manual RemovalManual removal is a traditional method for removing damaged refractory bricks. After the furnace has been sufficiently cooled, workers use pneumatic picks, crowbars, hammers and other tools to break and remove the damaged bricks.This method requires relatively little equipment and is suitable for small repair areas. However, it is labor-intensive and relatively slow, with significant noise and dust during demolition.2. Mechanical RemovalMechanical demolition commonly uses hydraulic breakers or similar equipment to remove refractory linings.Compared with manual removal, mechanical equipment can significantly reduce labor intensity and improve working efficiency. However, the impact force and demolition depth must be carefully controlled. Improper operation may damage the furnace shell, furnace structure or the refractory layer that needs to be retained.3. Controlled BlastingControlled blasting may be considered for large-scale refractory lining or furnace demolition projects.The blasting plan must be professionally designed according to the furnace structure, refractory thickness and demolition area. Strict safety measures are also required.Controlled blasting can provide a short demolition period and is suitable for large-scale projects, but it involves higher technical and safety requirements and must be performed by qualified professionals.4. Comparison of Removal MethodsMethodAdvantagesDisadvantagesSuitable ApplicationsManual RemovalLow equipment cost, flexible operationSlow and labor-intensiveSmall repair areasMechanical RemovalHigher efficiency, lower labor intensityHigher equipment cost, risk of structural damageMedium and large furnace repairsControlled BlastingVery fast for large-scale demolitionHigh technical and safety requirementsLarge-scale demolitionConclusionThe appropriate refractory brick removal method should be selected according to the furnace type, lining condition, demolition area, construction schedule, equipment availability and safety requirements.Manual removal is generally suitable for small repair areas, while mechanical demolition can be considered for medium and large furnace maintenance. For large-scale demolition projects, professional engineers may evaluate whether controlled blasting is appropriate.After removing the damaged refractory bricks, the remaining lining and furnace structure should be inspected and cleaned before installing new refractory bricks or refractory castables.

Hazardous waste incineration produces complex slags that may contain Na₂O, K₂O, CaO and other alkali or alkaline-earth oxides. These components can cause severe chemical corrosion to refractory linings. Therefore, suitable refractory materials are essential for hazardous waste rotary kilns.Common refractory materials include SiC castables, Al₂O₃-SiO₂ castables and Al₂O₃-Cr₂O₃ chrome corundum castables.SiC castables provide good slag resistance and wear resistance, but they may oxidize under high-temperature oxidizing conditions. Al₂O₃-SiO₂ castables generally have good thermal shock resistance, but Al₂O₃ and SiO₂ can react with Na₂O, K₂O and CaO in the slag, accelerating refractory corrosion.Chrome corundum castables are mainly composed of Al₂O₃ and Cr₂O₃. They offer excellent high-temperature stability, wear resistance and chemical corrosion resistance, making them suitable for severe operating conditions such as combustion zones of hazardous waste rotary kilns.Main AdvantagesExcellent slag corrosion resistanceHigh-temperature resistanceGood wear and erosion resistanceGood volume stabilitySuitable for severe hazardous waste incineration conditionsApplication ConsiderationsThe potential formation of Cr(VI) should also be considered when using chrome corundum castables in hazardous waste rotary kilns. CaO and alkali or alkaline-earth oxides in the slag may promote the oxidation of Cr(III) to Cr(VI). Therefore, the refractory formulation should be designed according to slag composition, operating temperature, furnace atmosphere and construction conditions, with proper installation and drying procedures.

Incinerator castables should be selected according to operating temperature, corrosive gases, fly ash erosion, and wear conditions. Common types include high-alumina castable, silicon carbide castable, mullite castable, lightweight insulating castable, and acid-resistant castable.1. High-Alumina CastableFeatures: Mainly made from high-alumina bauxite, corundum and other refractory materials. It offers high refractoriness, good wear resistance and high-temperature strength.Applications: Suitable for furnace chambers, flue ducts and other high-temperature areas subject to moderate wear.2. Silicon Carbide CastableFeatures: Excellent wear resistance, thermal shock resistance and corrosion resistance. It is particularly suitable for areas exposed to high-speed fly ash erosion.Applications: Commonly used in the first-pass flue of waste incinerators, waste heat boilers and other high-temperature, high-wear areas.3. Mullite CastableFeatures: Provides high-temperature strength, excellent thermal shock resistance and good stability under repeated temperature changes.Applications: Suitable for furnace walls, flue ducts and areas exposed to significant thermal stress and temperature fluctuations.4. Lightweight Insulating CastableFeatures: Low bulk density and low thermal conductivity, providing effective thermal insulation and reducing heat loss from the furnace body.Applications: Mainly used as a backup lining, insulation layer and thermal insulation material for lower-temperature flue ducts.5. Acid-Resistant CastableFeatures: Provides good resistance to acidic gases and chemical corrosion, helping improve lining durability in complex operating environments.Applications: Suitable for flue ducts and other areas exposed to corrosive gases such as HCl and SO₂.ConclusionThe selection of incinerator castables should be based on actual operating conditions. In waste incinerators with complex working environments, different castables are normally selected for different zones according to temperature, wear and corrosion conditions, improving the overall refractory, wear-resistant and corrosion-resistant performance of the lining.

Power plant boilers mainly include pulverized coal boilers and circulating fluidized bed (CFB) boilers. Different areas of the boiler are exposed to different temperatures, abrasion, erosion and thermal shock conditions, so suitable refractory castables should be selected according to the actual operating environment.1. Slag-Resistant Wear-Resistant CastableThis castable provides high strength, excellent abrasion resistance, erosion resistance and slag resistance.Applications: Boiler furnaces, slag coolers and areas exposed to severe abrasion, erosion and slag attack.2. Steel Fiber Wear-Resistant CastableSteel fibers are added to improve mechanical strength, impact resistance and thermal shock resistance, providing better resistance to spalling.Applications: Coal feeding openings, slag coolers, furnace areas, superheaters and cyclone separator inlets.3. Wear-Resistant Self-Flowing CastableSelf-flowing castables have excellent flowability and can fill complicated structures and narrow areas with minimal vibration.Applications: Membrane walls, inertial separators, corners and areas where vibration casting is difficult.4. Thermal Shock Resistant CastableThis type of castable provides high refractoriness, strength and thermal shock resistance, making it suitable for areas with frequent temperature fluctuations.Applications: Ignition air ducts, water-cooled air chambers and other areas subject to rapid temperature changes.5. High-Strength High-Alumina CastableHigh-alumina castables offer high strength, abrasion resistance, impact resistance, penetration resistance and corrosion resistance.Applications: Boiler arches, roofs, rear walls and other high-temperature areas.6. Corundum-Mullite Wear-Resistant CastableBased mainly on corundum and mullite, this castable provides high strength, excellent wear resistance, high-temperature performance and good thermal shock resistance.Applications: Boiler furnaces and other high-temperature, highly abrasive areas.Common Application AreasRefractory linings in CFB boilers are exposed to intense particle circulation and abrasion. Common application areas include:Boiler furnace and dense-phase zoneCoal feeding openingsReturn feedersCyclone separatorsSlag coolersIgnition air ductsWater-cooled air chambersBoiler roofs and wallsSuperheaters and other highly erosive areasSelection ConsiderationsRefractory castables should not be selected based only on service temperature. Abrasion, erosion, thermal shock, slag corrosion, construction method and equipment structure should also be considered.For CFB boilers, particular attention should be paid to abrasion resistance, high-temperature strength, thermal shock resistance and erosion resistance.