Decarbonation of geothermal waters by seeding with aragonite crystals coupled with air bubbling

Fil, H El; Manzola, A.S.; Amor, Mohamed Ben

doi:10.1016/s0883-2927(03)00013-1

Cited by 10 publications

(5 citation statements)

References 8 publications

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“…The supersaturation coefficient ( Ω ) decrease with the nucleation time allows suggesting the occurrence of an heterogeneous CaCO 3 nucleation. Indeed, it was shown that the metastability of the calcocarbonic system CaCO 3 ‐CO 2 ‐H 2 O can be immediately broken, for more lower supersaturation coefficients, after adding seed particles of calcite, SiO 2 or other inert materials as the PVC. In our experimental conditions, the dependence of CaCO 3 precipitation kinetics on ferric content allows suggesting that iron (III) precipitate plays this role of seed.…”

Section: Resultsmentioning

confidence: 99%

Speciation of Fe(II) and Fe(III) effect on CaCO₃ crystallization

Mejri

Salah

Tlili

2015

Crystal Research and Technology

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The present work was carried out to investigate separately the effect of Fe 2+ and Fe 3+ on the precipitation kinetics and the microstructure of CaCO 3 . For this an experimental procedure was proposed. Precipitation tests were made by using the dissolved-CO 2 degassing method. Both air and nitrogen were employed to strip the CO 2 from a Ca(HCO 3 ) 2 solution initially rich in this gas. At anoxic medium, it was shown that iron (II) prolongs the nucleation step and decelerates the crystalline growth rate. X-ray diffraction analysis shows that its presence inhibits calcite and promotes aragonite variety. By using air, the reaction medium is rich in oxygen and iron (II) is rapidly oxidized. Seeing the higher solution pH (> 6.5), iron hydroxide forms before the onset of CaCO 3 precipitation and plays a role of seed permitting to initiate CaCO 3 nucleation. So, contrary to the observed effect of iron (II), the presence of iron (III) accelerates the precipitation rate of CaCO 3 . As for iron (II), iron (III) inhibits calcite formation but favored the vaterite variety instead of the aragonite one.

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Section: Resultsmentioning

confidence: 99%

Speciation of Fe(II) and Fe(III) effect on CaCO₃ crystallization

Mejri

Salah

Tlili

2015

Crystal Research and Technology

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“…This is evident in Figure 6B, where, at flowrates greater than 5 L min -1 , there is no significant increase in the rate at which calcium is removed. The rate of CaCO3 formation could be increased by increasing the operating temperature, which would decrease the 𝐾𝐾 𝑠𝑠𝑠𝑠,𝐶𝐶𝑎𝑎𝐶𝐶𝐶𝐶 3 (Stumm and Morgan, 2012) or by adding seeds, which would increase the 𝑘𝑘 𝐶𝐶𝑎𝑎𝐶𝐶𝐶𝐶 3 (El Fil and Manzola, 2003;Song et al, 2006). The results ultimately show that it is important to have a rate of CO3 2formation greater than the precipitation rate of CaCO3, but the CO2 dissolution rate should be small enough to allow for substantial calcium removal before the buffer capacity of the solution is depleted.…”

Section: Understanding the Processes Involvedmentioning

confidence: 99%

Calcium removal from stabilized human urine by air and CO2 bubbling

2021

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“…The scaling power of real geothermal water, where an extensive scaling takes place in the cooling towers, was also assessed. 33 The geothermal water reaches the surface having a temperature and a pH of about 65°C and 6.8, respectively. Its Ca hardness is around 10 mM with HCO 3 Ϫ concentration of about 2 mM and an ionic strength close to 0.07.…”

Section: Evaluation Of the Novel Saturation Index For Some Experimentmentioning

confidence: 99%