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Solubilities of sideronatrite and ferrinatrite in the system Na2SO4- Fe2O3-H2SO4-H2O.

Flynn CM Jr.; Eisele JA
Reno, NV: U.S. Department of the Interior, Bureau of Mines, RI 9100, 1987 Jan; :1-17
The solubilities of sideronatrite [Na2Fe(OH)(SO4)2.3H2O] and ferrinatrite [Na3Fe(SO4)3.3H2O] were determined by the Bureau of Mines in the Na2SO4-Fe2O3-H2SO4-H2O system at 25 deg, 40 deg, 60 deg, and 90 deg C. The solution compositions investigated ranged from Na+-Fe3+ mol ratios of 0.5 to > 100 (Na2SO4 saturation) and H+- SO4 2- mol ratios of 0 to 1.0. The results are presented in the form of contour plots. The solubilities were determined by seeding supersaturated solutions of known composition with the specified solid phase to precipitate a substantial amount of solid. Water was then added in small portions to the solution until the last portion of the solid dissolved. Equilibration times at 25 deg, 40 deg, 60 deg, and 90 deg C were 2 days, 1 day, 8 to 16 h, and 2 to 4 h, respectively. The accuracy of the solubility data is estimated to be 1 to 2 pct. Low iron solubilities of < 0.36 pct Fe2(SO4)3, or 1 g Fe/kg solution, were obtained in solutions containing at least 8 pct Na2SO4 in the absence of H2SO4 or a total of at least 36 to 38 pct Na2SO4 + H2SO4 at high acidity. The filterability and density of sideronatrite and ferrinatrite in comparison with other iron compounds are reported. These compounds are suitable vehicles for iron removal in Na2SO4-rich solutions. Additional solubility data on the Na2SO4-H2SO4-H2O system were also obtained.
Hydrometallurgy; Iron-sulfate; Solubility; Metalliferous-minerals; Mining-research; Materials-recovery; Iron-inorganic-compounds; Siderite; Ferrite
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IH; Report of Investigations
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Reno, NV: U.S. Department of the Interior, Bureau of Mines, RI 9100
Page last reviewed: November 19, 2021
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