14. Appendix. Appendix Substances and solvents. Magnesium sulfate hydrates. Transition point: MgSO 4 7H 2 O MgSO 4 6H 2 O at 48.

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1 14. Appendix 14.1 Substances and solvents Magnesium sulfate hydrates Transition point: MgSO 4 H 2 O MgSO 4 6H 2 O at 4.1 C /OTT02/ MgSO 4 H 2 O Magnesium sulfate heptahydrate Mineral name: epsomite Mol wt: Purchased from: Merck (pure) 0 µm MgSO 4 H 2 O crystals MgSO 4 6H 2 O Magnesium sulfate hexahydrate Mineral name: hexahydrite Mol wt: 22.4 Purchased from: Fluka (puriss. p.a.) 0 µm MgSO 4 6H 2 O crystals 113

2 Zinc sulfate hydrates Transition point: ZnSO 4 H 2 O ZnSO 4 6H 2 O at 3.0 C /ROH02/ ZnSO 4 H 2 O Zinc sulfate heptahydrate Mineral name: zinc vitriol Mol wt: 2.55 Purchased from: Merck (pure) 0 µm 0 µm ZnSO 4 H 2 O crystals L-Phenylalanine Transition point C H 11 NO 2 H 2 O C H 11 NO 2 at 3.0 C /MOHN01/ C H 11 NO 2 or C 6 H 5 CH 2 CH(NH 2 )CO 2 H L-Phenylalanine anhydrate Mol wt: Purchased from: Lancaster (assay, formula >%) 0 µm C H 11 NO 2 crystals 114

3 Borax hydrates Transition point: Na 2 B 4 O H 2 O Na 2 B 4 O 5H 2 O at 60. C /SMI02/ Na 2 B 4 O H 2 O di-sodium tetraborate decahydrate Mineral name: tincal, borax Mol wt: 31.3 Purchased from: Merck (extra pure) 0 µm Na 2 B 4 O H 2 O crystals Calciumchloride hydrates Transition point CaCl 2 4H 2 O CaCl 2 2H 2 O at 45.3 C /KEM02/ CaCl 2 2H 2 O Calciumchloride dihydrate Mineral name: sinjarite Mol wt: Purchased from: Merck (cryst. GR for analysis) 0 µm CaCl 2 2H 2 O crystals 115

4 Stearic acid Transition point B C between 2-32 C /BEC4, SAT4, SAT5/ C 1 H 36 O 2 Stearic acid Mol wt: 24.4 Purchased from: Merck 0 µm stearic acid crystals Methanol Methanol, dried, max % H 2 O, Merck 116

5 14.2 Additives CaSO 4 2H 2 O Calcium sulfate dihydrate, Merck (precipitated, GR for analysis) FeSO 4 H 2 O Iron(II) sulfate hydrate, Merck (extra pure) H 2 SO 4 Sulfuric acid, Merck (5-%, extra pure) KCl Potassium chloride, Merck (GR for analysis) KH 2 PO 4 Potassium dihydrogen phosphate, Merck (GR for analysis) K 2 SO 4 Potassium sulfate, Merck (cryst. GR for analysis) MgCl 2 Magnesium chloride, Merck (anhydrous, for synthesis) Na 2 B 4 O H 2 O di-sodium tetraborate decahydrate, Merck (GR for synthesis) NaCl Sodium chloride, Merck (extra pure) NaOH Sodium hydroxide, Riedel-de Haën (GR for analysis) Na 2 SO 4 Sodium sulfate, Riedel-de Haën (anhydrous, GR for analysis) NiSO 4 6H 2 O Nickel(II) sulfate hexahydrate, Merck (GR for analysis) 11

6 14.3 Ultrasonic velocity of magnesium sulfate solutions Ultrasonic velocity of magnesium sulfate solutions for concentrations between 25 and 4 wt%. ultrasonic velocity [m/s] concentration [-] ultrasonic velocity [m/s] The ultrasonic velocity y in aqueous magnesium sulfate solutions in dependence on temperature x 1 and concentration x 2 can be correlated by the following equation: y = a + b x c x 2 d x1 e x 2 f x1 x 2 Variables for concentrations between 0-25 and 25-4 wt% magnesium sulfate variables concentration 0-25 wt% 25-4 wt% (R 2 = 0.4) (R 2 = 0.3) a b c d e f

7 14.4 Solubility of magnesium sulfate in aqueous solution Comparison between own experimental data (exp.) and data from literature (lit.) /SEI65/. concentration [MgSO4 / 0 H2O] 60 epsomite - lit. epsomite - exp. 55 hexahydrite - lit. hexahydrite - exp Solubility of epsomite saturation concentration [g anh. / 0g H 2 O] (exp.) (lit.) ** ** ** Solubility of hexahydrite saturation concentration [g anh. / 0g H 2 O] (exp.) (lit.) 20.0** ** ** ** solubility of the metastable phase 11

8 Supersolubility of epsomite concentration [g anh. / 0g H 2 O] saturation nucleation T max * [K] Supersolubility of hexahydrite concentration [g anh. / 0g H 2 O] saturation nucleation T max * [K] * average of 3-5 measurements with ultrasound, K / h, seed crystal, moderate stirring 120

9 14.5 Influence of additives on the solubility of magnesium sulfate Additive Concentration [wt%] -- ph: CaSO 4 2H 2 O FeSO 4 H 2 O H 2 SO 4 ph: KCl KCl KCl KH 2 PO K 2 SO K 2 SO MgCl MgCl MgCl Na 2 B 4 O H 2 O Na 2 B 4 O H 2 O Na 2 B 4 O H 2 O Na 2 B 4 O H 2 O Na 2 B 4 O H 2 O Na 2 B 4 O H 2 O NaCl NaCl NaOH ph: Na 2 SO Na 2 SO NiSO 4 6H 2 O Saturation temperature [ C] 121

10 14.6 Metastable zone (maximum allowable supercooling) of magnesium sulfate in aqueous solution with additives,5 CaSO 4 2H 2 O FeSO 4 H 2 O KH 2 PO 4,5,5,5,5,5 pure 0.1 wt% CaSO4 3 3,2 3,4 3,6 3, 4 4,2 pure 20 ppm Fe2SO4.H2O 1 t% Fe2SO.H2O4 3 3,2 3,4 3,6 3, 4 4,2 pure 1 wt% KH2PO4 3 3,2 3,4 3,6 3, 4 4,2 122

11 ,5 K 2 SO 4,5 pure 2 wt% K2SO4 5 wt% K2SO4 3 3,2 3,4 3,6 3, 4 4,2,5 MgCl 2,5 pure 0.1 wt% MgCl2 1 wt% MgCl2 2 wt% MgCl2 3 3,2 3,4 3,6 3, 4 4,2,5 NaCl,5 pure 2 wt% NaCl 5 wt% NaCl 3 3,2 3,4 3,6 3, 4 4,2 123

12 ,5 Na 2 SO 4,5 pure 2 wt% Na2SO4 5 wt% Na2SO4 3 3,3 3,6 3, 4,2 4,5 4,,5 NiSO 4 6H 2 O,5 pure 1 wt% NiSO4.6H2O 3 3,2 3,4 3,6 3, 4 4,2,5 ph,5 pure (ph 6.4) ph 2.5 ph. 2, 3 3,2 3,4 3,6 3, 4 4,2 124

13 14. Solubility of zinc sulfate heptahydrate in aqueous solution Solubility of zinc sulfate heptahydrate saturation concentration [g anh. / 0g H 2 O] ** ** solubility of the metastable phase + solubility of zinc sulfate hexahydrate Supersolubility of zinc sulfate heptahydrate concentration [g anh. / 0g H 2 O] saturation nucleation T max * [K] * average of 3-5 measurements with ultrasound, K/h, seed crystal, moderate stirring 125