[Kinetics of the growth of Ca oxalate crystals from supersaturated solutions].

Several factors influencing the nucleation and growth of Ca-oxalate crystals from metastable and instable solutions were studied in some detail. Factors of interest were the absolute concentration of calcium respectively oxalate, the quotient oxalate/calcium, repeated additions of calcium and/or oxalate, the presence or absence of crystal seeds, the agitation respectively stagnation of the metastable Ca-oxalate solution, the duration of crystallization, etc. The striking findings are the eminent role of oxalate in the formation of big crystals and crystal aggregates, the distinct inhibition of crystal growth at higher and very high calcium concentrations, as well as the substantial crystal enlargement at the presistent oxalate load.