Hydrothermal synthesis of AlPO 4-5 type zeolitic materials by using aluminum dross as a raw material

Abstract

The hydrothermal synthesis of AIPO 4-5, which is one of the large pore size aluminum phosphate condensates like zeolitic materials, was carried out by using aluminum dross as a raw material. Triethylamine (TEA) was used as a structure directing agent (SDA) for AIPO 4-5 synthesis. Various physical properties such as crystal structure, surface texture and specific surface area were investigated for the obtained reaction product. AlPO 4-5 can be synthesized from aluminum dross under hydrothermal conditions at 453–473 K for 3 h. AlPO 4 salt as a by-product, which is a non-porous material, is formed at the same time. The crystal of the obtained AlPO 4-5 is hexagonal as observed by SEM photographs. It is desirable to heat-treat the reaction product at the temperature around 823 K to remove TEA. The crystal structure of AlPO 4-5 changes to non-porous aluminum phosphate in case of a heat treatment exceeding 973 K. The specific surface areas of the reaction product before and after heat treatment at 823 K are 18 and 360 m 2/g, respectively.