Degradation Resistance of Graphite in Contact with Industrial Phosphoric Acid Mixed with an Oxidizing Agent Through Dynamic and Static Approaches

Phosphoric acid (PA) is an industry-relevant chemical. However, a contaminated PA is produced when it is prepared industrially by the wet process from natural phosphates. The resulting PA can only be marketed internationally until a purification process has been carried out. Consequently, an oxidizing agent (Ox) is added to eliminate these organic impurities and purify PA. However, the optimum concentration of the Ox and its effects when combined with PA on the components that make up the machinery utilized for the purification process, notably the graphite, were unknown. The present study is performed to determine the impact of different doses of the Ox when mixed with the PA media on the graphite and to investigate its resistance to degradation through two procedures, static and dynamic immersion process. The mechanical properties of graphite have been studied by means of three-point bending tests. Findings showed that the weight reduction was insignificant in comparison to that achieved in the absence of the oxidant. However, it increased considerably as the oxidant dose reached its maximum. In general, it can be concluded that the addition of oxidizing agent to PA is not harmful to graphite while the Ox concentration is within an optimal concentration level.