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 CO, to create calcium carbonate. The results showed that fresh PG at filter cake contained the P₂O₅ total of 1.38%, and the phosphorus pentox ides 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 diffrac- tion (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.