Solubility Study of Nickel Ferrite in Boric Acid Using a Flow-Through Autoclave System under High Temperature and High Pressure

The solubility of nickel ferrite in an aqueous solution of boric acid was studied by varying the pH at the temperatures ranging from 25°C to 320°C. A flow-through autoclave system was specially designed and fabricated to measure the solubility of Fe in hydrothermal solutions under high temperature and pressure. The performance of this flow-through system was directly compared with the conventional static state technique using a batch-type autoclave system. The stability of fluid velocity for the flow-through autoclave system was verified prior to the solubility measurement. The influence of chemical additives, such as boric acid and H2, on the solubility of nickel ferrite was also evaluated.