Open AccessCharacterisation of Purified Gypsum and Insoluble Impurities Obtained from Phosphogypsum Waste
Author(s) -
Lazar Kaludjerovic,
Josip Išek,
Nikola Vuković,
Maja Milošević
Publication year - 2021
Publication title -
inżynieria mineralna
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.215
H-Index - 9
ISSN - 1640-4920
DOI - 10.29227/im-2019-01-13
Subject(s) - phosphogypsum , gypsum , impurity , raw material , residue (chemistry) , chemistry , sulfate , solubility , recrystallization (geology) , mineralogy , chromatography , materials science , metallurgy , geology , organic chemistry , paleontology
In this study, the chemical and phase composition of two samples of phosphogypsum from the waste dumps of the Industry of ChemicalProducts “Elixir – Prahovo” (Serbia) were examined, as well as the possibility of recrystallization of gypsum from an aqueoussuspension of phosphogypsum. The negative effect of higher temperatures on the solubility of calcium sulfate (13.08 mmol/dm3 at95°C vs. 15.43 mmol/dm3 at 40°C) was utilized. In several repeated cycles, calcium sulfate component was progressively dissolvedin water at room temperature and then precipitated at 100°C, using the same liquid phase throughout the experiment. Therefore,phosphogypsum was separated into recrystallized (purified) gypsum, insoluble residue and supernatant, and the mass balance forthe experiment was calculated. Elemental, XRD and SEM-EDS analyses were performed on raw phosphogypsum, purified gypsumand insoluble residue. The whiteness of raw phosphogypsum and purified gypsum were determined and compared. The main objectiveof the study was to investigate the nature of insoluble impurities, in order to define and optimize the methods for their removalduring a potential industrial processing of phosphogypsum.