Drying characteristics of ammonium polyvanadate under microwave heating based on a thin-layer drying kinetics fitting model

The dried ammonium polyvanadate (APV) can be used to produce high-purity Vanadium pentoxide (V2O5) by calcination. Therefore, drying is a necessary process. The advantages of microwave drying are uniform heating, selective heating, high heating efficiency and the operation process is clean and hygienic. This study uses a microwave to dry APV and discusses the effect of the initial mass, microwave power, initial moisture content on the drying efficiency of APV. The results display that the average drying rate is positively correlated with the microwave output power. When the initial mass is 35 g, the average rate is shown as 0.000263%/s. As the initial moisture content and power of APV increases to 25% and 560W, the average drying rate increases to 0.00036231%/s and 0.003125%/s, respectively. At the same time, through the analysis of APV drying kinetics and the fitting of experimental data, it is found that the APV microwave drying process can be precisely described by the Modified Page model. The microwave heating process saves energy and time, directly penetrates the product, and has certain advantages in green metallurgy.