磷石膏是磷肥行业的主要废弃物：环境挑战和价值化机遇(1).pdf

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1、Phosphogypsum as the main waste of P-fertilizers industry:environmental challenges and valorization opportunities1Presented by:Abdellatif ElghaliIn collaboration with:Fatima AkfasMIT Global Summit on Mine Tailings Innovation21.Phosphate value chain and PG generationIt is about food security.Very sta

2、ble mineral(apatite).Soluble fertilizers(NPK or others).3The wet process to produce phosphoric acidCa5(PO4)3F+5H2SO4+10H2O 3H3PO4+HF+5(CaSO4.2H2O)70-80C1324Grinding and conditioning of the phosphate rockDissolution of the phosphate rock with H2SO4(60 wt.%)Washing of PG by waterFiltrationSubject to w

3、ide compositional variation and many substitutions in the crystal structure.Phosphate ore The major elemental composition of PG varies depending on the type of wet phosphoric acid process used.The minor element composition may vary greatly following the source of the phosphate rock.These elements un

4、dergo processes like precipitation into a mineral phase,co-precipitation,entrapment in pores,adsorption,absorption onto organic or inorganic surfaces.Dissolution precipitation reactionH2SO4 at 70-80CSPCaO(Akfas et al.,2024),(Akfas et al.,2023),(El Zrelli et al.,2019),(Rutherford et al.,1994)1.Phosph

5、ate value chain and PG generation4(Caruso et al.,2016),(Maest et al.,2005),(Gaudry et al.,2006),(Tayibi et al.,2009)Huge environmental footprint+11 billion t of PG to be generated by 2050 World most significant wasteEnvironmental issues related to phosphogypsum storage2.Environmental challenges of P

6、G management 5SpainTunisiaTunisiaDumped in SeawaterPG management strategiesSurface storage Restricting through global environmental policies:the UN Sustainable Development Goals,the Paris Agreement on Climate Action,the International Maritime Organizations London Convention,and the broader dedicatio