In what form is arsenic most stable when solidified?
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RT: In what form is arsenic most stable when solidified?
I seem to have seen a similar question on HaiChuan; I remember it saying that elemental arsenic is non-toxic, and that there is currently no technology capable of extracting elemental arsenic.
It is said that iron arsenate – smaltite is the most stable.
Arsenic sulfide, or processed into sodium arsenate
Stibnite doesn’t seem to be of much use; even after being solidified at high costs, it still has to be used to fill valleys.
Currently, the main focus is on producing arsenic trioxide or converting it into ferric arsenate
Ferric arsenate, calcium arsenate – vitrified sintered curing is the most stable
Ferric arsenate is the most stable; it suffices to oxidize arsenic to the +5 valence state and then precipitate it with lime, but sufficient amounts of ferric ions are required
Data shows that iron arsenate dihydrate (allanite), when placed in water in natural conditions for 11 years, has an arsenic content of less than 0.003 mg/l; therefore, among arsenic compounds, allanite is the most stable. In the fixation of arsenic, it is crucial to oxidize trivalent arsenic to pentavalent arsenic; moreover, allantoinite can be formed only in the presence of trivalent iron ions. Oxidation and control of the pH value are key factors. Oxidation using the Fenton technique, combined with proper control of reaction conditions, can effectively immobilize arsenic.