Polarography in Fused Alkali Metaphosphates.

A New Concept for Producing White Phosphorus: Electrolysis of Dissolved Phosphate in Molten Chloride

“…Gruber 9 filed a patent in 1957 to produce phosphorus by electrolyzing molten NaPO 3 . Caton et al 10 in 1963 successfully obtained phosphorus by electrolyzing molten NaPO 3 or LiPO 3 -KPO 3 . However, these studies did not result in a practical production.…”

“…Extraction of phosphorus by electrochemical techniques may be an alternative to carbothermic reduction due to the advantages in simplicity and cleanness. Several attempts in history can be found. − Metaphosphates with low melting points were once utilized as the electrolyte. Gruber filed a patent in 1957 to produce phosphorus by electrolyzing molten NaPO 3 .…”

“…However, these studies did not result in a practical production. Metaphosphates are not suitable to perform the role as an electrolyte due to the large viscosity. , Laitinen et al in 1966 and Franks et al in 1970 studied the electroreduction behavior of sodium phosphates in molten LiCl-KCl or NaCl-KCl. However, no proof of phosphorus formation was given in their paper, perhaps due to the poor diffusion of phosphate in the above-mentioned chlorides.…”

Efficient Electrosynthesis of White Phosphorus from Molten Condensed Phosphate Salts

“…Historically, the electrolysis of molten metaphosphates has been investigated in the context of a potential flux for metal electrodeposition (16)(17)(18)(19)(20)(21)(22)(23)(24)(25), although research in this area was largely abandoned in the early 1970s. While the electroreduction of metaphosphates was observed with concomitant evolution of P4, these studies provide few quantitative insights or synthetic handles for maximizing the efficiency or selectivity of phosphate reduction, limiting the development of practical phosphorus electrosynthesis technologies.…”

“…Even with a carbon anode, such electrosynthesis emits half as much CO2 per molecule of P4 as the incumbent process; the carbon footprint may be further reduced by the incorporation of oxygen-evolving anodes (19,25). Further extending this work to lower-melting condensed phosphate eutectics, such as lithium-potassium metaphosphate (MP 518 °C), could enable a combined concentrated solar thermal/electrochemical approach to carbon-neutral P4 synthesis powered solely by renewable energy sources (21,48,49). In a decarbonized future economy, such electrolytic phosphorus synthesis may one day 'short-circuit' the thermal process entirely.…”