Comparative study of fresh phosphogypsum treatment by sulfuric acid and neutralization with NaOH and CO₂

Abstract

The newly formed, fresh phosphogypsum (PG) at the filter cake of the Dinh Vu Diamoni photphate DAP fertilizer factory was studied and treated with dilute sulfuric acid. The impurities were removed by sulfuric acid treatment and the carbonatation by NaOH and CO2 to create calcium carbonate. The results showed that fresh PG at filter cake contained the P2O5 total of 1.38%, and the phosphorus pentoxides effectively were removed at 69.32%. The acid‐treated PG was neutralized by NaOH and CO2 aeration, creating CaCO3 in situ nano‐microparticles identified by scanning electron microscopy (SEM) images and CaCO3 intensity by X‐ray diffraction (XRD). In this study, the cement mortar test, which used treated PG from both sulfuric treatment and NaOH neutralization within CO2 aeration, has better compressive strength properties and hydration supported by SEM images, XRD results, and thermogravimetric analysis.