The Hydrolysis Behavior of Antimony Trichloride and Phase Transformation Mechanism of Hydrolysates with the Effect of Arsenic

Arsenic-containing SbCl 3 solution is a typical leachate in the extraction of antimony from antimony ores and smelting residues. Efficiently controlling the hydrolysis behavior of antimony and arsenic is crucial for obtaining target antimony products and remove impurity arsenic. This study mainly investigates the hydrolysis behavior of arsenic and antimony in arsenic-containing SbCl 3 solution by manipulating As(III)/As(V) concentration, temperature, the hydrolysis ratio and Cl − concentration. Meanwhile, the composition and phase transformation mechanism of hydrolysates are analyzed. The results reveal that during the hydrolysis of Sb(III), As(III) almost does not hydrolyze, while As(V) hydrolyzes concurrently with Sb(III). With increasing As(V) concentration, the hydrolysates of Sb(III) shift from crystalline Sb 4 O 5 Cl 2 to Sb 8 O 8 (OH) 6 · x Cl 2 and finally to amorphous arsenate antimonates. Furthermore, the increase of the hydrolysis ratio promotes the phase transformation of the hydrolysates from Sb 4 O 5 Cl 2 to Sb 8 O 8 (OH) 6 · x Cl 2 , while elevated temperature inhibits the occurrence of this transformation. Variation of Cl − concentration will not have a significant impact on the hydrolysis process and the phase of the hydrolysates. According to the composition of hydrolysates, for obtaining antimony hydrolysates with lower As(V) content, it is recommended to minimize the As(V) concentration, control a moderate hydrolysis ratio (1:8–1:12) and increase the hydrolysis temperature during the hydrolysis process.