Sorption purification of nickel solutions of metal impurities

The paper discusses the possibility of sorption purification of nickel solutions of zinc, copper and iron in the production of nickel sulphate reagent of “Fine chemicals” grade with resins having functional groups, such as aminodiacetic (Lewatit TP207); bis-2,4,4-trimethylpentyl-phosphinic acid (Lewatit TP272); aminophosphonate (Purolite S940). The values of static (SOY) and dynamic (DOE) exchange capacity of investigated sorbents for impurity metals in technological solutions of the composition (g/dm3) are defined: 147.6 Ni; 2.02 Zn; 0.36 Cu; 0.17 Fe; 9.8 H2SO4, and model binary “nickel-metal” solutions (g/dm3): 75.9-88.6 Ni; 7.1 Zn; 0.52 Cu; 0.34 Fe; 4.7 H2SO4. In the static mode the increase of the ratio of volumes of the sorbent and the solution (sol/liq) leads to the increase of the metal extraction degree. When sol/liq = 0.1, the metals most completely extracted from technological solutions in resins are, in %: Cu, > 60 (TP207) and Fe (III), ≈ 50 (S940), while simultaneous sorption of other metals does not exceed 8-14 % of the original content. Sorption isotherms of metal impurities from model solutions according to values of correlation coefficients (R2 > 0.95) are satisfactorily described by Langmuir and Freundlich models. The use of the sorption technology does not allow to perform sufficient purification of solutions from impurity metals, which is made by the use of step extraction with D2EHPA and Versatic 10.