Health & Environmental Research Online (HERO)


Print Feedback Export to File
1754940 
Journal Article 
EFFLUENT-FREE MANUFACTURE OF AMMONIUM PARATUNGSTATE (APT) BY RECYCLING THE BY-PRODUCTS 
Vadasdi, K 
1995 
Yes 
International Journal of Refractory Metals and Hard Materials
ISSN: 0958-0611 
13 
1-3 
45-59 
WOS:A1995RF39400005 
Within the framework of a review of the fundamental
processes applied for the manufacture of ammonium paratungstate (APT) the main byproducts and
wastes generated in these processes and their environmental impact are summarized. A subsidiary
process based on the electrodialytic recovery of NaOH for the elimination of the salt byproduct,
which is generated in the largest quantities, is outlined together with the main aspects to be
taken into account for large-scale industrial implementation. The present stage of development
and implementation of an APT production line for the processing of typical scrap material from
the light filament industry is shown, as well as the oxidizing and dissolving process of compact
and lumpy tungsten alloy scrap (Cu-W, Fe-Ni-W) and hard metal scrap (Co-WC, Co-WC-Ta(Nb)C-TiC).
Several as yet unexploited potentials are sketched which could, from scientific and engineering
standpoints, be interesting for the development of more efficient intermediate manufacturing
processes for APT and tungsten or process operation for a wide variety of raw materials.