1. Preparation process optimization
   The preparation of exterior wall ceramic insulation boards needs to take into account both the mechanical and thermal properties of the materials. The core processes include raw material selection, forming methods and sintering systems:

Raw material formula: Mineral raw materials such as kaolin, quartz and feldspar are used. The thermal conductivity is reduced by adding lightweight and porous materials such as diatomite and expanded perlite. For example, a certain study reduced the thermal conductivity of the sheet to 0.068 W/(m·K) by adding 15% diatomite.
Forming technology: Wet pressing forming can improve the uniformity of sheet density, while extrusion forming is more suitable for continuous production. Experiments show that the flexural strength of wet-pressed sheets is 20% higher than that of extruded ones.
Sintering system: Rapid sintering (with a heating rate of 10℃/min) is prone to cause abnormal grain growth and reduce mechanical properties. The stepped sintering (holding at 800℃ for 1 hour and then heating to 1200℃) can reduce the water absorption rate of the sheet to less than 3%.

2. Thermal performance improvement mechanism
   The optimization of the thermal performance of ceramic insulation boards should be approached from two aspects: microstructure regulation and composite modification.

Microstructure regulation: Reduce the thermal conductivity by introducing closed pores. For example, the closed porosity of the board prepared by the foaming agent method reaches 75%, and the thermal conductivity can be reduced to 0.045 W/(m·K).
Composite modification: Surface coating with silica aerogel can increase the thermal resistance of the sheet by 30%, while incorporation of graphene nanosheets (0.5wt%) can enhance the thermal stability of the sheet by 15% within the temperature range of -20 ° C to 60 ° C.

3. Durability verification methods
   Durability tests need to simulate actual working conditions, covering freeze-thaw cycles, thermal shock aging and chemical erosion.

Freeze-thaw cycles: According to the GB/T 50082 standard, the mass loss rate of the sheet after 100 freeze-thaw cycles should be ≤5%, and the strength retention rate should be ≥80%. A certain study shows that the mass loss rate of the board mixed with fibers is only 2.1% after 150 cycles.
Thermal shock aging: During the rapid cooling and heating cycles from 800℃ to 20℃, the crack resistance of the sheet material must meet the requirement of no penetrating cracks after 50 cycles. Experiments show that the thermal shock life of the plate with zirconia phase change material added is extended to 80 times.
Chemical erosion: The acid and alkali resistance test should comply with the JG/T 287 standard. After the sheet is soaked in a 5% sulfuric acid solution for 72 hours, the mass loss rate should be ≤1%.

4. Engineering application verification
   The long-term performance of the sheet material needs to be verified through on-site testing:

Thermal performance monitoring: In a certain demonstration project, the heat transfer coefficient of the building’s exterior wall using ceramic insulation boards dropped to 00.35 W/(m²·K), saving 15% energy compared to traditional EPS boards.
Durability tracking: Tests on the exterior walls of buildings that have been in use for five years show that there is no peeling on the surface of the panels, and the thermal conductivity only increases by 0.01 W/(m·K), verifying its long-term stability.

5. Technical and economic analysis
   Cost-effectiveness needs to be evaluated from the perspective of the entire life cycle:

Preparation cost: Using industrial waste residue as raw material can reduce the cost of the board to 80 yuan per square meter, which is 20% lower than that of traditional rock wool boards.
Energy-saving benefits: Based on the 65% building energy-saving standard, ceramic insulation boards can reduce the heating energy consumption per unit area to 12 kWh/(m²·a), with an annual energy-saving benefit of 30 yuan /m².
Conclusion and Prospect
Significant progress has been made in the preparation process, thermal performance and durability of exterior wall ceramic insulation boards, but the following problems still need to be solved:

Standardized production: Establish a complete quality control system from raw materials to finished products.
Multi-functional integration: Develop composite boards with both self-cleaning and moisture-regulating functions.
Intelligent application: Real-time monitoring and early warning of sheet performance are achieved by integrating Internet of Things (iot) technology.