The Preparation Conditions Of The Carrier. Coprecipitation Synthesis Of Nzp Family Optimization Study

The preparation conditions, which were used to synthesize NZP family compound supported by coprecipitate method were studied. Furthermore, the NZP family porous ceramics support was obtained by adding pore-forming agent and their performances were tested. In addition, how to enhance the thermal shock resistance and the thermal conductivity of NZP family porous ceramics support were also investigated. The results indicate that:1. The pH value, concentration and temperature of solution, and the dispersion methods had the prominent effect on the performances of NZP family compound support. The suitable condition was that the pH value was 8; the concentration of ZrOCl₂·8H₂O was 0.2moll^-1; the concentration of (NH₄)₂HPO₄ was 0.6moll^-1; the reaction temperature was room temperature; the calcining heat was 650°C. Under this reaction condition, the surface areas was 60.7～68.0m²g^-1; the average particle size was 1.41～2.00μm; and the granularity was well-proportioned. The agglomeration could be prevented by dispersing of ethanol abstersion and ultrasound.2. The experimental results showed that the NZP family compound support prepared by adding 10%La₂O₃ or 10%CeO₂ possessed good thermal stability, and the surface areas was 20.1m²g^-1 after being calcined in 900°C.3. The NZP family porous ceramics support were obtained by adding 50% graphite or 45% starch, dry pressing molding and sintering in 1100°C. The performances were as follows: porosity under (33.8～35.8%), compressive strength (29.37～45.23MPa) and surface areas (under 0.4m²g^-1), which was needed to coat a second support to increase surface area as catalysts support.4. The CBZP porous ceramics support added 1% active SiO₂ had the best thermal shock resistance, and the its thermal expansion curves had the least hysteresis loops.5. The NZP family porous ceramics support had the small thermal conductivity, which was only 2.41W/m°C, and it was found that adding1～7% SiC could not improvethe thermal conductivity, though, as catalysts support, it was needed to introduce other effective reagent to improve the thermal conductivity.