Mehanochemical synthesis of calcium oxalate from calcium sulfate

Kalcijevi oksalati su sastavni dio bubrežnih kamenaca i oni su kalcijeve soli oksalne kiseline. Sve više ljudi u današnje vrijeme ima problema sa bubrežnim kamencima stoga su istraživanja na tu temu sve intenzivnija, najviše se istražuju procesi taloženja kalcijevih oksalata te načini njihova mogućeg uklanjanja ili prevencije njihova nastanka. U medicinskom smislu ovaj problem se naziva urolitijaza ili nefrolitijaza. Ovisno o uvjetima, kalcijev oksalat može kristalizirati u tri hidratna oblika, kalcijev oksalat monohidrat (COM) koji je termodinamički najstabilniji, te metastabilni dihidrat (COD) i trihidrat (COT) koji se vrlo rijetko može naći u sastavu bubrežnih kamenaca. U ovom radu je cilj bio provjeriti koji hidratni oblik kalcijeva oksalata nastaje mehanokemijskom sintezom i to na dva načina, bez dodatka otapala (samo praškasti reaktanti) i s dodatkom minimalne količine otapala, u ovom slučaju vode. Dobiveni rezultati su obrađeni i interpretirani FT-IR spektroskopijom, termogravimetrijskom analizom te optičkom mikroskopijom.Calcium oxalates are components of kidney stones and they are calcium salts of oxalic acid. Nowadays more and more people have problems with kidney stones therefore research on this subject are more intensive, mainly precipitation processes of calcium oxalate and the ways of their possible removal or prevention of crystal growth. In medical way this problem is known as urolithiasis of nefrolithiasis. Depending on conditions, calcium oxalate cristallizes in three hidrate forms, calcium oxalate monohydrate (COM) which is thermodynamically most stable, and metastable dihydrate (COD) and trihydrate (COT) which is the rarest to be found in kidney stone composition. The goal of this work was to see which hydrate form of calcium oxalate will form by mechanochemical synthesis and it was done in two ways, without adding minimum quantity of solvent (only pulverised reactants) and with adding a minimum quantity of water, in this case water. Results were processed and interpreted with FT-IR spectroscopy, thermogravimetric analysis and optical microscopy