The synthesis of large scorodite particles in non-ferrous metallurgical industries usually requires a high-cost operation involving heating and high-pressure autoclaving. To overcome these obstacles, an atmospheric-pressure process for scorodite synthesis (DMSP~R) was developed, in which ferrous ions were oxidized by oxygen gas in the presence of pentavalent arsenic ions. This process gives scorodite of good crystallinity with particle sizes as large as 15-20 urn. The solutions used for scorodite synthesis in the DMSP~R are prepared from various residues containing arsenic from non-ferrous smelters. The solutions may be contaminated with Cu, Sb, and Bi, for example, and therefore the effects of such impurities on the formation of crystalline scorodite need to be investigated. In this study, the effects of Cu, Sb, and Bi contaminants on the formation behaviors of scorodite particles in the DMSP~R were investigated systematically.
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