BIOTITA E FLOGOPITA COMO FONTE ALTERNATIVA DE POTÁSSIO PARA FERTILIZANTE: EXTRAÇÃO HIDROMETALÚRGICA.

Biotite and phlogopite as alternative sources of potassium for fertilizer production: hydrometallurgical extraction

Abstract

Biotite and Phlogopite are minerals of micas, constituents of rocks and available in various tailings or mineral resources. They are alternative sources of potassium for fertilizer production, but not yet commercial exploitation on a large scale, due to the lack of commercial technology that makes the business viable. The objective of this work was to evaluate the hydrometallurgical recovery of the potassium of these two minerals by leaching with sulfuric acid. The expected product was a solution containing potassium sulphate. The biotite source is a rock from the Carajás - Pará and the phlogopite comes from the Serra da Carnaíba - Bahia. The leaching was performed in a 5L rollers bottle rotated at 10rpm for 36h at room temperature (25°C). The particle size was 100% <1mm. The recovery of the potassium of the biotite in solution reached 67% for a mass ratio of H₂SO₄/rock of 0.85mL/g whereas for phlogopite the recovery was 33% for the same dosages. The dissolution of the potassium of the biotite varies proportionally to the increase of the chemical potential (free H₂SO₄) whereas phlogopite does not suffer great variations, but tends to increase. The biotite has a higher potassium release potential for fertilizer production than phlogopite.

Keywords: Fertilizer. Potassium. Hydrometallurgy. Biotite. Phlogopite.