1. New Development in Dihydrate - Hemihydrate processes: first industrial experiences of the new Prayon DA-HF process Prayon: Tibaut Theys, Dorina Fati, Olivier Schrevens Grupa Azoty: Agata Tarnowska, Monika Zienkiewicz 1

2. Contents 2 1.Introduction 2.Test Design 3.Test Results 4.Lessons Learned

3. Introduction 3 Five process routes exist to produce phosphoric acid (DH, DH-HH, HH, HRC and HDH) Technologies are in public domain Prayon invests in R&D to improve plant efficiency and profitability One high newcomer: DA-HF process

4. Introduction 4 DA-HF pilot tests showed promising results High efficiency High P 2 O 5 in acid Stable operation Two industrial tests organised to confirm results and gain industrial know how In collaboration with Grupa Azoty (Poland)

5. Industrial Test Design 5 Di Attack – Hemi Filtration Di Attack 36 % P 2 O 5 Hemi Filtration 32% P 2 O 5 3% SO 3  – 

6. Industrial Test Design 6 Plant design - Dihydrate Nominal capacity: 150 tpd P 2 O 5 4 compartments 225 m³ Slurry cooled by flash cooler Filter : 40 m² useful – dry discharge 123 4 FC Filter

7. Industrial Test Design Filter 1234 FC Steam H 2 SO 4 Plant design – DA-HF

8. Test Process Parameters 8 DH residential time: 3h30 @ 100% capacity HH residential time: 1h20 @ 100% capacity Solids content DH: 25 – 30% SO 3 DH: 0.7 to 1 % SO 3 HH: 2.5 to 5 % Temp DH : 74 – 76 °C Temp HH : 97 – 99 °C %P 2 O 5 acid produced: 32 -34%

9. Test Results 9 Quality of acid and gypsum Calcium sulphate filterability Efficiency Plant operation

10. Test Results - Analyses with Egyptian Rock 10 ElementsUnit Rock Egypt Acid DH Gypsum (250°C basis) Acid HH Hemihydrate (250°C basis) P 2 O 5 WS% w/w28.536.03 32.850.2 P 2 O 5 UN% w/w 1.16 0.19 P 2 O 5 CO% w/w 0.78 0.29 Crystal water % w/w 19.60 6.22

11. Test Results - Analyses with Moroccan Rock 11 ElementsUnit Rock Morocco Acid DH Gypsum (250°C basis) Acid HH Hemihydrate (250°C basis) P 2 O 5 WS% w/w30.737.4 32.850.2 P 2 O 5 UN% w/w 1.42 0.11 P 2 O 5 CO% w/w 0.59 0.32 Crystal water % w/w 19.60 6.3

12. Test Results - Filterability 12 DH operation first test DA-HF operation Egypt rock DA-HF operation Morocco rock Conversion Slurry temperature°C7695 Filtrate Density20°C1.3081.4441.460 Filtration rate : Atm. Pressure (local) (mmHg)760 Filter Vacuum(mmHg)500 Filtration cycle(s)180 Filtration rate(TPD P 2 O 5 /m 2 )3.84.25.4

13. Test Results – DH Crystals 13 Small individual crystals No clusters Slurry easy to pump

14. Test Results – HH Crystals 14 Clusters Ball shape Aggregates easy to filter

15. Test Results – Efficiency 15 Industrial values observed: 97 – 98% To be compared with a DH process results by GA : 91 – 94%

16. Test Results – Plant Operations 16 Some difficulties due to filter hopper not designed for HH operation (solids accumulation) Operators could easily operate the plant Start-up and shut downs are as easy as for DH process Flash cooler to be operated at lower pressure

17. Lessons learned for conversion of existing DH plant 17 Most DH plants can be converted to DA-HF technology Main changes to be considered: Installation of a conversion tank Improvement of cooling capacity Adaptation of filter

18. Conclusion 18 DA-HF process can be operated on an industrial basis Increase of plant efficiency : about 2 to 4 % Acid produced with higher P 2 O 5 content : above 32% P 2 O 5 Existing DH plant conversion can be considered

19. Thank you for your attention ! 19 Contact: Tibaut THEYS Tel: +32.4.273.93.41 Fax: +32.4.275.09.09 prt@prayon.be