Abstract

BALDERRAMA FLORES, Fausto Alfredo  and  QUISPE CHOQUE, Romer Lorgio. Cryptomelane lixiviation in acid solutions of ferrous sulfate. Rev. Met. UTO [online]. 2015, n.37, pp. 40-44. ISSN 2078-5593.

Abstract It has been studied the effect of the rate mineral/water, temperature, concentration of ferrous sulfate and sulfuric acid concentration on the extraction of manganese, a mineral from the Uyuni zone in the department of Potosi. The mineral studied contains 37.16% of Mn, and mineralogical analysis by X-ray diffraction indicated that consists mainly of cryptomelane (KMn₈O₁₆) and quartz (Si0₂). The study in the laboratory indicates that the solution of ferrous sulfate in an acidic medium is an excellent lixiviating agent for this mineral. With a solid concentration of 100 grams of mineral per kilogram of water, temperature of 15 °C, size of particles of -48 +65 #Ty, ferrous sulfate concentration of 1.25 times the stoichiometric concentration, concentration of sulfuric acid of 1.25 times the stoichiometric, agitation speed of 350 rpm and 2 hours of lixiviation, an extraction of 99.7% manganese was achieved. If the temperature of lixiviation is increased to 45 °C, and the size of the grain is decreased to -65 Ty, it's possible to decrease the lixiviation time at least 1 hour. Lixiviation temperatures above 45°C are detrimental to the process, because it's created a precipitate which contains dissolved manganese and reduces its extraction.

Keywords : Lixiviation; manganese minerals; cryptomelane..