Quartz solubility in sodium carbonate solutions at high pressure and temperature

In-situ Raman spectroscopic analysis of dissolved silica structures in Na2CO3 and NaOH solutions at high pressure and temperature

“…Even using the lowest estimation, the enhancing effect of the Na 2 CO 3 on quartz solubility in aqueous fluids was confirmed. The quartz solubility increased at greater Na 2 CO 3 concentrations, which is consistent with previous experimental data for up to approximately 4.7 m Na 2 CO 3 solutions obtained at 300-450 °C and an unspecified P (Friedman 1948), and for 0.3-3.5 m Na 2 CO 3 solutions obtained at 500-700 °C, and 0.4 and 0.5 GPa (Aranovich et al 2020). The measured solubilities were generally similar to the values for 0.50 and 1.50 m Na 2 CO 3 solution at 0.4 or 0.5 GPa calculated by linear interpolation of the Aranovich et al's (2020) data, except for the slightly higher results at 648 °C (1.3 GPa) and 730 °C (1.5 GPa) (Fig.…”

“…Comparisons with previous solubility data in Na 2 CO 3 solutions Aranovich et al (2020) determined the quartz solubility in 0.2-3.5 m Na 2 CO 3 solutions at conditions of 500, 600, and 700 °C and 0.4 GPa, and 600 °C and 0.5 GPa, using an internally heated pressure vessel and a phase assemblage bracketing method. Those authors showed a slight increase of quartz solubility in the Na 2 CO 3 solutions with increasing P and T. Figure 2 shows that our measured solubilities in 0.50 m Na 2 CO 3 solutions at 579 °C (0.92 GPa), 635 °C (0.84 GPa), and 695 °C (1.42 GPa), and 1.50 m Na 2 CO 3 solutions at 558 °C (1.20 GPa) and 629 °C (1.41 GPa) overlapped, within errors, with the calculated values from the Aranovich et al ( 2020) experiments at 0.4 and 0.5 GPa.…”

“…These experiments were conducted at near-neutral pH conditions, whereas the solubility behavior of quartz in high pH fluids could provide some insights into the nature of alkaline fluids in subducting lithologies such as crustal pelite (Galvez et al 2015(Galvez et al , 2016, crustal basalt (Galvez et al 2016), and sediments (Connolly and Galvez 2018). The enhanced silica solubility in high pH fluids has been confirmed by early and recent studies on supercritical Na 2 CO 3 or NaOH solutions (Friedman 1948;Anderson and Burnham 1967;Schmidt 2014;Aranovich et al 2020). Aranovich et al (2020) have systematically investigated quartz solubility in Na 2 CO 3 and NaOH solutions at 500-700 °C and 0.4 and 0.5 GPa using an internally heated pressure vessel and a phase assemblage bracketing method.…”

“…The enhanced silica solubility in high pH fluids has been confirmed by early and recent studies on supercritical Na 2 CO 3 or NaOH solutions (Friedman 1948;Anderson and Burnham 1967;Schmidt 2014;Aranovich et al 2020). Aranovich et al (2020) have systematically investigated quartz solubility in Na 2 CO 3 and NaOH solutions at 500-700 °C and 0.4 and 0.5 GPa using an internally heated pressure vessel and a phase assemblage bracketing method. The results showed the quartz solubility systematically increased with greater salt concentrations, reaching 4.1 m [mol kg H 2 O -1 ] of silica in 3.5 m Na 2 CO 3 and 2.4 m silica in 2.2 m NaOH.…”

“…These curves were lower than our lowest estimation of quartz solubility. Aranovich et al (2020) also reported that the quartz solubility in Na 2 CO 3 solutions based only on the above species underestimated the values at lower pressure ranges (0.4 and 0.5 GPa). Our solubility data, together with those of Aranovich et al (2020), indicated that the available speciation modeling was insufficient to explain the high quartz solubilities and aqueous speciation in the Na 2 CO 3 solution at high P-T conditions.…”