Resumen

DI YORIO, C; RANGEL, C; BETANCOURT, E  y  Y RUS, J. Lixiviación dinámica de NI y CO a presión atmosférica de laterita utilizando ácido sulfúrico y cítrico con posterior precipitación selectivaDINAMIC LEACHING OF Ni AND Co AT ATMOSPHERIC PRESION OF LATERITE USING SULPHURIC AND CITRIC ACID WITH LATER SELECTIVE PRECIPITATION. Rev. Fac. Ing. UCV [online]. 2006, vol.21, n.1, pp.29-37. ISSN 0798-4065.

The following work studies the dynamic leaching of a nickeliferous laterite with sulphuric and citric acid to hydrometallurgically extract nickel and cobalt. After the leaching process, it was investigated the selective precipitation of nickel and cobalt in both acid solutions. The laterite ore and the precipitates were characterized to obtain their particle morphology and chemical composition by means of X rays diffraction, electron microscopy and quantitative chemical analysis. During the leaching process, acids concentration were varied from 0.5M, 1M and 3M for the sulphuric acid and 0.1M, 0.2M y 0.5M for the citric acid, at a 20% of pulp density and a temperature variation between ambient, 60ºC and 80ºC. At 80ºC it was obtained recoveries of nickel of 73.4% in sulphuric acid and 20.29% in citric acid, meanwhile it was achieved recoveries for cobalt in the order of 46.29% and 38.88 in sulphuric and citric respectively (4 hours leaching). Also it was tested to recirculate the liquor and the leached pulp for three times. It was obtained 551.2 mg/l of nickel and  .3 mg/l of cobalt in the liquor with recoveries up to 40% for Ni and 46% for Co. The  technique was based in lime addition to the sulphuric acid solution where the pH for precipitation occurs around 4, with 86.45% of the nickel and 57.31% of the cobalt reported in the precipitate; meanwhile in citric solution water steam and CO2 was added separately to displace the metallic cation associate to the quelate in the leaching solution, besides to preserve the citric acid in the solution. The quantity of the nickel and cobalt that precipitate was 48.84% and 62.06% respectively.

Palabras clave : Leaching; precipitation; nickel; cobalt; sulphuric acid; citric acid; chelate.