A new procedure of phosphogypsum purification in order to diminish the content of radionuclides

• Autorzy: Rajković M.B. , Tošković D.

Warianty tytułu

PL

Nowa metoda oczyszczania fosfogipsu z radionuklidów

• Języki publikacji: EN

Abstrakty

EN

Phosphogypsum obtained by "wet procedure" for phosphoric acid production is actually calcium-sulphate dihydrate, CaSO4×2H2O, which contains a high percentage of impurities as well as radionuclides originating from the basic raw material used for the production, i.e., phosphate. In the technology of phosphoric acid production by "wet procedure", phosphogypsum is intended to be a "sponge" that absorbs all impurities from phosphoric acid (except uranium) and to be left in deposits as the unnecessary burden. Since enormous amounts of phosphogypsum result from phosphoric acid production (the ratio is 5:1), phosphogypsum deposits are the problem per se, as far as environmental protec-tion is concerned, because they occupy large areas and may contaminate the air, underground waters, as well as water flows that receive phosphogypsum in the form of 2% suspension. In the procedure proposed, phosphogypsum is trans-formed into hemihydrate, CaSO4×0.5H2O, which corresponds to natural gypsum, and the impurities which are present in this compound are in accordance with natural gypsum composition. By removing radionuclides with barium-sulphate, 226Ra isotope content decreases below the maximum permissible concentration, but this process is directly dependent on the type of the phosphate utilized in phosphoric acid production.

PL

Fosfogips to dwuwodny siarczan wapnia (CaSO4×2H2O) otrzymywany podczas produkcji kwasu fosforowego "metodą mokrą". Fosfogips zawiera znaczne ilości zanieczyszczeń, a wśród nich radionuklidy pochodzące z podstawowego surowca-fosforanu (fosforytu). W technologii produkcji kwasu fosforowego "metodą mokrą" fosfogips powinien mieć strukturę gąbczastą, aby absorbować wszystkie zanieczyszczenia (poza uranem). Fosfogips jest składowany jako nieprzydatny odpad. Ponieważ w czasie produkcji kwasu fosforowego powstają znaczne ilości fosfogipsu (w stosunku 5:1), więc składowiska tej substancji, zajmujące olbrzymie tereny, stanowią poważny problem w ochronie środowiska. Dodatkowo mogą być przyczyną zanieczyszczenia powietrza, wód podziemnych i powierzchniowych, do których fosfogips może dostawać się w postaci 2% zawiesiny. W proponowanej metodzie oczyszczania fosfogips jest przekształcany w półwodzian, (CaSO4×0,5H2O), który odpowiada naturalnemu gipsowi, jego zanieczyszczenia zaś są charakterystyczne dla naturalnego gipsu. Usunięcie radionuklidów za pomocą siarczanu baru obniża zawartość izotopu 226Ra poniżej dopuszczalnego stężenia, jednakże proces ten jest bezpośrednio zależny od rodzaju fosforanu (fosforytu) użytego do produkcji kwasu fosforowego.

• Wydawca: Oficyna Wydawnicza Politechniki Wrocławskiej
• Czasopismo: Environment Protection Engineering
• Rocznik: 2003
• Tom: Vol. 29, nr 2
• Strony: 45--64
• Opis fizyczny: Bibliogr. 24 poz., rys., tab.

Twórcy

autor

Rajković M.B.

• Institute of Food Technology and Biochemistry, Department of Chemistry and Biochemistry, Faculty of Agriculture, University of Belgrade, P.O. Box 127, YU-11081 Belgrade-Zemun, Yugoslavia.

autor

Tošković D.

• Faculty of Technology, Zvomik, University of Serbian Saraevo, Republic of Srpska

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