High temperature calorimetric studies of the heat of solution of La2O3 in silicate liquids

摘要: Abstract High temperature calorimetry at 1760 K has been used to measure the heat of solution La2O3 in a series simple alkali and alkaline earth silicate liquids. The these solvents is strongly exothermic varies as function liquid composition. However, variation does not follow trends related cation size or charge little with concentration. composition reflects ability La(III) perturb transient framework compete other cations for oxygen. This complex pattern melt energetics consistent recent spectroscopic measurements which suggest extreme perturbation by La(III), sufficient isolate oxygen from silicon. interpretation suggests presence phase-ordered regions rich incipient liquid–liquid immiscibility suggested previous calorimetric studies. Within error capacity La-bearing liquids same over super-cooled range stable liquid, no evidence large capacities associated restructuring. Thus are dominated reactions form La-clusters do dissociate increases up K.