Factors Affecting the Precipitation of Potassium Jarosite in Sulfate and Chloride Media

Abstract

The factors affecting the precipitation of potassium jarosite in both sulfate and chloride media were systematically investigated for the range of conditions likely to be encountered in hydrometallurgical practice. In sulfate solutions at 97°C, the amount of precipitate increases with increasing retention times up to 10 hours, with increasing temperatures to approximately 100°C, and with increasing ferric-ion concentrations. Despite the variations in the amount of precipitate, the composition remains nearly constant and is characteristic of that of potassium jarosite. The presence of potassium jarosite seed accelerates the rate of precipitation and results in near-maximum amounts of precipitate after just a few hours of reaction. The presence of ferrous sulfate has a negligible effect on both the product yield and composition. The amount of precipitate decreases with increasing acid concentrations, but the composition of the precipitates remains nearly constant, even for acid concentrations as high as 1.0 M H 2 SO 4 . Both the amount and composition of the precipitates vary as the K 2 SO 4 concentration increases; in the presence of excess ferric ions, nearly complete K precipitation occurs. Small amounts of Cu 2+ , Zn 2+ , and Pb 2+ are incorporated in the structure of potassium jarosite, and the amount increases with increasing concentrations of the divalent metal ions. Potassium jarosite is readily formed in chloride media at 140°C, provided that an independent source of sulfate ions is available. A minimum K concentration is required in order to avoid the formation of hematite; at higher K concentrations, however, the product composition becomes nearly constant and reflects that of potassium jarosite. Both the product yield and composition are independent of the chloride concentration, added as LiCl, and the ferrous ion concentration, added as FeCl 2 . Although increasing concentrations of HCl result in a near-linear decrease in the amount of precipitate, the composition is independent of the HCl concentration and is characteristic of that of potassium jarosite. Increasing temperatures to 200°C result in an increase in the product yield, but have no significant effect on the composition of the potassium jarosite precipitates.

A Two‐Step K‐Ar Experiment on Mars: Dating the Diagenetic Formation of Jarosite from Amazonian Groundwaters

“…Decreasing the K content of the jarosite increases its model age in this scenario. However, as described above, K‐rich jarosite is geochemically likely (Dutrizac, ). For a reasonable lower compositional limit of 1:1 K:Na, the model age of the jarosite alone is 4.25 ± 0.66 Ga.…”

The unique environment of the most acidified permanently meromictic lake in the Czech Republic

“…Compared to the bottom samples, the very low K + surface concentrations may be explained by the precipitation of particular sulphate minerals (K-jarosite) (Dutrizac, 2008). Additionally, priority uptake by plants for the synthesis of organic matter could also be involved (Pitter, 2009).…”

A Review on Various Aspects of Jarosite and Its Utilization Potentials

“…Many studies have focused on efficiency-enhancing of removal systems and obtaining better working conditions. Among various methods applied in removal efficiency enhancement such optimizing working condition and utilizing more appropriate materials [1][2][3][4]. Jarosite is a promising approach and it is an effective scavenger for metals in iron and sulfate rich acidic solutions.…”

“…Diverse jarosite group minerals are formed based on the substitution of A with cations. The A sites can be occupied by monovalent (K, Na, Ag, Tl, H3O), divalent (Ca, Sr, Ba, Pb), trivalent and quadrivalent (Th, U) ions [1][2][3]. Their mineral names, synthetic equivalents, the substitution of A and formulas are listed in Table 1.…”

“…Although biologically and chemically synthesized samples show some variation in their physical properties, chemical analysis helps to identify and categorize each type. Sodium jarosite and ammonium jarosite are costeffective than potassium jarosite and therefore, more commonly used in industry [2,3].…”