Potassium extraction from the silicate rock Verdete using organic acids

Although Brazil is one of the world's leading exporter agricultural products, country highly dependent on importation potassic fertilizers. K-bearing silicate rocks are reported as potential solutions to reduce external K dependency. This work evaluated extraction from Verdete rock, a glauconite-bearing rock containing 10 % K2O, by solubilization with organic acids. Firstly, was reacted during 3-120 h citric or oxalic acid at 2 (m/v) in Erlenmeyer flasks shaking. Oxalic extracted 6.5 Verdete, while 2.3 %. Another experiment performed evaluate effect various concentrations (2, 4, 6, 8, and %) differing reaction times (12, 24, 48, 72 h) rock. Soluble concentration nearly doubled increase time 12 h, rising 20 37 mg L–1. Increments were obtained increasing up 6 above this concentration, no significant gain observed. The X-ray diffraction data showed that resulted formation oxalate-metal complexes metals