Experimental work in the Al 2 O 3 -H 2 O system at high pressure is largely restricted to corundum solubility experiments conducted at pressures of under 0.6 GPa. Results often differ by roughly an order of magnitude at the same conditions, probably due to equilibration problems. Only the work of Becker et al. Time series experiments indicate that equilibrium was obtained in less than 70 hours. In some cases, solubilities were also measured by weight loss, which showed close agreement to the ICP-AES results.
Solubility increases with increasing temperature and with increasing pressure.
Our results demonstrate that aluminum solubility is substantial at moderate temperature and high pressure. Aluminum may therefore be readily transported in medium-grade regional metamorphism or in subduction zones and the assumption of aluminum immobility is inappropriate in these environments. HCl is one of the most important components of hydrothermal fluids when considering mass transport. The solubility of charged species is pH dependent so a thorough understanding of material transport capability of such fluids depends on the dissociation of HCl. The present experiments measure directly the solubility of Cl at higher pressures.