Recovery of tungsten by liquid-liquid extraction from a wolframite concentrate after fusion with sodium hydroxide

摘要

This work presents the results of the tungsten recovery from a wolframite concentrate (61.5% WO_3) from Igarape Manteiga (Rondonia - Brazil) after fusion with NaOH followed by leaching with water. The optimum fusion conditions required temperatures above 550 °C to avoid partial manganese leaching. 98.6% of tungsten was leached as Na_2WO_4 after fusion at 650 °C for 1 h. More than 99% of the element was extracted in one stage with Aliquat 336 or Alamine 336 (5-10 vol.% in kerosene, A/O = 1 (v/v), 25 °C). Stripping was easily performed in one stage ( > 99.9%) with 2 mol L~(-1) NH_(3(aq)) (A/O= 1 v/v, 25 °C) when Alamine 336 was the extractant. Tungsten was recovered as ammonium paratungstate (APT).