Solubility of annabergite

The solubility of annabergite is characterized by the concentrations of Ni and As. TCLP tests showed that there was a little poorly crystalline product in the annabergite synthesized by the authors.The long-term solubility tests were conducted to evaluate the stability of resultant product and the results showed that the dissolution of annabergite gradually reached equilibrium after 15 days. The solubility was strongly dependant on the pH of the medium with the concentrations of Ni and As decreasing remarkably with increasing pH.The lowest concentrations were 48 mg·L -1 As and 0.2 mg·L -1 Ni at pH 9.Nickel and arsenic of annabergite dissolved at the same step[n(Ni)∶n(As)=1.5]with the theoretical figure of molecular formula, but the Ni/As molar ratio was much lower than the theoretical figure because of Ni(OH)_2 precipitated. The solubility of annabergite was much lower than that of Nishimura et al’s.