Chemical Properties of Tungsten and Tungsten Compounds

Yih, Stephen W. H.; Wang, Chun T.

doi:10.1007/978-1-4899-5025-3_7

Cited by 1 publication

(2 citation statements)

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“…The theoretical total charge required for the complete reduction of 2.5 g of CaWO 4 was 5027 Coulombs as calculated from Eq. [3] by taking 100% current efficiency. As it can be seen in Figure 5, complete reduction of CaWO4 was obtained in the experiments except the one that employed 2.0 V base potential.…”

Section: Resultsmentioning

confidence: 99%

“…Although scheelite is the most abundant mineral of tungsten, wolframite is used more than scheelite due to easier dissolution in alkaline solutions used in present processing methods (2). The present production method of tungsten starts by first producing intermediate tungsten bearing compounds, converting them to ammonium paratungstate (APT) and then converting APT to tungsten oxide and then reducing tungsten oxide to tungsten by a reducing agent, such as carbon or hydrogen, depending on the targeted purity (3). Due to large number of steps involved and high energy consumption in conventional production method, alternative production methods have been investigated for a long time (4)(5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

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A Pulse Voltage Application in Electrochemical Reduction of Solid CaWO₄Powder

Goksu¹,

Erdogan²,

Karakaya

2016

ECS Trans.

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Scheelite is the most abundant mineral of tungsten, but wolframite is used more than scheelite due to easier dissolution in alkaline solutions used in present processing methods. An alternative method based on electrochemical reduction of CaWO4 by direct current applications in molten salt solutions was recently reported. Pulse voltage and constant voltage reduction mechanisms were compared and an optimization of reduction kinetics was achieved in this study. The results have shown that faster reduction rates could be achieved during pulse voltage applications compared to constant voltage applications, when average value of pulse voltage application was the same as its constant counterpart. Furthermore, analysis of charge, energy and theoretical reduction graphs showed that reduction of calcium tungstate occurs at higher potential differences than 2.2 V, between calcium tungstate and graphite.

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Section: Resultsmentioning

confidence: 99%