Solvent extraction of molybdenum (VI), tungsten (VI) and rhenium (VII) by diisododecylamine from leach liquors

• Published in: Hydrometallurgy Vol. 60; no. 1; pp. 1 - 5
• Main Authors: Gerhardt, N.Iatsenko, Palant, A.A, Petrova, V.A, Tagirov, R.K
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2001
• Subjects: Molybdenum; Rhenium; Tungsten; Molybdenum; Tungsten; Rhenium
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/S0304-386X(00)00123-7

Solvent extraction of molybdenum (VI), tungsten (VI) and rhenium (VII) by diisododecylamine (DIDA) from leach liquors encountered in the processing of tungsten and molybdenum ores was studied. This study applies results published previously. Solutions formed during the oxidizing roasting operation of molybdenite sulphide concentrates obtained from a wet dust collector (1.15 g/L Re and 18.6 g/L Mo, 1.1 M H 2SO 4) and leach liquor formed during the autoclave soda decomposition process of wolframite concentrates were used. The organic phase comprised 15% v/v technical grade DIDA (86% DIDA+14% tri- n-octyl amine (TOA)) in ‘light’ kerosene (boiling point 200–250°C) without modifiers. Recovery of tungsten and molybdenum in organic phase using a second stage extraction scheme was >99%, and the recovery of tungsten was 99.9% using the first stage of solvent extraction. However, the formation of stable dispersion was observed during the extraction of tungsten by DIDA from concentrated solutions (>100 g/L). The formation of stable dispersion can be avoided by diluting the solution to 50 g/L W (VI). Metals in the loaded organic phase were stripped quantitatively by aqueous ammonium solution at an aqueous/organic phase ratio ranging from 1:1 to 1:2 in either the first or second stage scheme. The organic phase was regenerated by treatment with 10% H 2SO 4 and was re-used in extraction. We demonstrate that DIDA is an extractant specific enough for rare refractory metals and that the co-extraction of such impurities as copper, magnesium, manganese, iron, aluminum and cobalt does not exceed 1–2%.