Purification of a Nigerian Wolframite Ore for Improved Industrial Applications
Increasing demands for pure wolframite ore in the form of ammonium paratungstate (APT), tungsten oxide cannot be over emphasized. Thus, treatment of a Nigerian wolframite ore containing admixtures of scheelite (CaWO4: 96-900-9631) and stolzite (PbWO4: 96-900-9813) by hydrometallurgical route was investigated in hydrochloric acid chelated with phosphoric acid to extract tungsten via solvent extraction. During leaching, parameters such as leachant concentration, chelate dosage and reaction temperature on ore dissolution were examined. At optimal conditions (1.5 mol/L HCl + 2.0 mol/L H3PO4 solution; 75 °C), 95.0% of the initial 10 g/L ore reacted within 120 min. The derived activation energy of 56.80 kJ/mol supported the proposed dissolution mechanism. The unreacted product analyzed by XRD was found to contain siliceous impurities. Tungsten recovery from leachate was carried out by solvent extraction with Aliquat 336 in kerosene. Pure tungsten was recovered as APT and beneficiated to produce high grade industrial tungsten oxide of industrial values.
KeywordsWolframite Scheelite Stolzite Hydrochloric acid Phosphoric acid Leaching Solvent extraction Tungsten Ammonium paratungstate
The authors wish to thank:
(i) CSIR–Institute of Minerals and Materials Technology, Bhubaneswar-751013, India for their benevolence in supplying the ALIQUAT 336 extractant used for this study;
(ii) I. N. Venantius Nig. Ltd. Located at No. 39, St. Finbarrs Road, Akoka, Lagos, Nigeria: A supplier of Scientific, Hospital Equipment, Laboratory furniture & fittings, Chemicals, Reagents and General Contractor; and
(iii) KAM Industries Nigeria Limited, Ilorin, Kwara State: One of the leading indigenous Steel Industries in Nigeria for their immeasurable supports for this research and part sponsorship to attend the TMS 2018 Meeting in Arizona, U.S.A.
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