What are the post-processing techniques for the preparation of ammonium fluorozirconate

In the field of modern purification technology, multi-stage separation and purification processes have become the standard configuration of the industry. The primary separation stage of this process combines high-speed centrifugation and ultrafiltration membrane technology, using a centrifugal speed of 10,000 r/min and a ceramic membrane with a molecular weight cutoff of 5,000 Da to effectively remove more than 90% of unreacted raw materials and by-products in the reaction system. This efficient primary separation lays a solid foundation for subsequent purification steps.

In the secondary purification stage, the process introduces a dual-channel purification mechanism of solvent extraction and ion exchange. In this process, tributyl phosphate has a selective extraction efficiency of more than 95% for fluorozirconate ions under weakly acidic conditions of pH=4.0. At the same time, the application of strongly acidic cation exchange resin can reduce the metal ion content to the order of 10??, ensuring the high purity of the final product. In the final purification stage, the regional melting technology is used to carry out directional solidification at a rate of 5℃/min in an argon protective atmosphere. This process can effectively eliminate dislocations and inclusions inside the crystal, so that the product purity reaches more than 99.99%.

Crystal structure control technology achieves crystal transformation and defect repair by precisely controlling heat treatment process parameters. In the temperature range of 200-300℃, when gradient annealing is performed, the in-situ X-ray diffraction monitoring system can capture the phase transition process from hexagonal phase to cubic phase in real time. This phase transition reduces the lattice distortion rate by 40%, significantly improving the thermal stability of the material. During the vacuum heat treatment process, the fluorine gas supply system successfully repairs the fluorine vacancy defects on the crystal surface by maintaining a vacuum degree of 10?3 Pa and precisely controlling the fluorine gas flow rate, thereby reducing the surface energy of the material to 1.2 J/m2, thereby enhancing its corrosion resistance.

Surface modification technology achieves directional control of material properties through the dual mechanisms of physical coating and chemical bonding. Atomic layer deposition (ALD) technology deposits 2-5 nm Al2O3 thin film on the surface of ammonium fluorozirconate crystals, which not only increases the specific surface area from 80 m2/g to 120 m2/g, but also significantly enhances the interfacial bonding strength through Al-O-Zr bonding, reducing the material's pulverization rate in extreme environments by 60%. Low-temperature plasma treatment technology introduces fluorine-containing active groups to form a dense fluoride protective layer on the crystal surface, significantly reducing the corrosion rate of the material in a high-temperature molten salt environment by 2 orders of magnitude.

Particle size control technology combines mechanical crushing and classification technology to achieve precise control of particle size. Ultra-low temperature airflow crushing is carried out in a liquid nitrogen environment at -196°C, and with an inertial classifier, the D50 particle size is precisely controlled in the range of 2-5 μm. This particle size distribution significantly improves the suspension stability of the material in the ceramic slurry by 3 orders of magnitude. Ultrasonic field-assisted grinding technology achieves uniform dispersion of nano-scale particles through the micro-jet impact generated by the acoustic cavitation effect, making the filling density of the material in the electronic slurry reach 92% of the theoretical limit.