Hairunnisha, S. and Sendil, G.K. and Prabhakarrethinaraj, J. and Srinivasan, G.N. and Adaikkalam, P. and Kulandaisamy, S. (2007) Studies on the preparation of pure ammonium para tungstate from tungsten alloy scrap. Hydrometallurgy, 85. pp. 65-71.

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Abstract

Ammonium paratungstate was prepared from tungsten alloy swarf employing anodic dissolution in sodium hydroxide using a packed bed configuration followed by chemical conversion into ammonium tungstate through tungstic acid. The alkaline tungstate solution was dialysed to recover sodium hydroxide, which could be recycled to the electrolytic dissolution. The influence of anodic current density and other parameters on dissolution/recovery was studied and discussed. It was observed that a current density of 600 mA/100 g scrap could be applied when the concentration of NaOH was maintained around 2.5 M. The energy consumption for anodic dissolution was 2.14 kWh/kg W with more than 90% recovery achieved. XRD studies indicated that the exhausted scrap contained an alloy of nickel and iron with a very low percentage of tungsten. APT sample prepared through anodic dissolution in NaOH was characterized.

Item Type:	Article
Uncontrolled Keywords:	Tungsten; Ammonium para tungstate; Anodic dissolution; Tungsten alloy scrap
Subjects:	Electrohydrometallurgy
Divisions:	UNSPECIFIED
Depositing User:	ttbdar CECRI
Date Deposited:	27 Mar 2012 15:43
Last Modified:	27 Mar 2012 15:43
URI:	http://cecri.csircentral.net/id/eprint/653

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