Insight into mineralizer modified and tailored scorodite crystal characteristics and leachability for arsenic-rich smelter wastewater stabilization

Abstract

The addition of appropriate mineralizers is a potentially effective strategy for the control of crystal growth, and could be used in the disposal and stabilization of arsenic-rich non-ferrous effluents.

The effect of precursor speciation on the growth of scorodite in an atmospheric scorodite synthesis

“…The result is consistent with XRD characterization that the growth of some crystal planes is inhibited. The scorodite with lamellar structure was also observed in a previous study, which was identified as incomplete developed scorodite [22].…”

Disposal of high-arsenic waste acid by the stepwise formation of gypsum and scorodite

“…The synthesis can be modied by using a catalyst or additives. 27,28 Owing to the above properties, scorodite is recognized as the best arsenic-stabilization mineral and attracts widely attentions. 16,17,[29][30][31][32][33][34][35][36][37][38][39][40][41][42] The synthesis of scorodite is of great importance for arsenic removal rate from a arsenic-bearing solution.…”

Arsenic immobilization as crystalline scorodite by gas-diffusion electrocrystallization

“…The product formed using As 3+ at a temperature of 70 °C was significantly bigger than in the other instances tested, which is desirable for lower leachability, because leaching is a heterogeneous process and thus the rate of leaching is directly proportional to the area of the product that is being leached out. 39 The larger particle size of scorodite produced at 70 °C is partly attributed to the higher synthesis temperature, which is one of the conditions to induce crystallinity in a precipitate. Yet, a higher temperature alone is not enough to induce crystallinity in scorodite; it requires the simultaneous control and maintenance of a low supersaturation environment.…”

“…42 Larger particle sizes, including non-homogeneous particles (from fine particles <1 μm to large particles >5 μm), were generated by a slow H 2 O 2 production rate at 70 °C, together with an enhanced dissolution caused by the more extended electrode polarization periods using As 3+ as the precursor (304 hours) vs. 50 hours using As 5+ as the precursor. Sun et al 39 demonstrated that scorodite undergoes crystal shape changes during aging, from a laminar to polyhedral to octahedral structure. This was here observed, and it seems to have contributed significantly to decrease As-leachability.…”