Nickel waste or sludge frequently contains higher copper, iron, cobalt, chromium, molybdenum, and other non-ferrous metals, and can take the extracted impurity separation process the recovery of nickel. After the nickel-containing waste is soaked and filtered by hot acid, the filtrate is adjusted to pH 1-3, sodium chlorate is added at 90 °C, Fe2+ is oxidized to Fe3+ in the solution, and 18% Na2CO3 solution is added dropwise to control the pH value of the process. , filtered after about 2h. The reaction that takes place in the process is as follows. 6FeCl2+NaCIO3+3H2O+6Na2CO3====6FeOOH↓+13NaCl+6CO2↑ The filtration performance of the resulting β-FeOOH precipitate was good. After iron removal by goethite method, the removal rates of iron and chromium were over 99%, and the recovery rates of cobalt and nickel were 91% and 99% respectively. The extracting agent N235 is a tertiary amine extracting agent having the formula (CnHm) 3N (m==15-21, n-7-10), and is monosulfonated with N235 (35%)-isooctanol (15%). coal oil (50%) as the organic phase. Because the maximum extraction rate of N235 to copper is only 70% in the co-extraction and impurity removal, and the residual copper and cobalt co-extraction affects the purity of cobalt when extracting nickel and cobalt, the copper should be removed before extracting and separating cobalt nickel. The active nickel powder was added at 1.2 times the theoretical amount. At 80 ° C, the solution of the iron and chromium after the crater (Ph=2) was added with lg of active nickel powder per liter to reduce the copper in the solution to o. 002 ~ 0.008 g / L; in addition to copper solution can be extracted by N235 separation of nickel, cobalt. When the chloride ion concentration in the solution is less than 100 g/L, 70% of Cu2+ and all of Fe3+ are extracted, and cobalt is hardly extracted; when the Cl- concentration in the solution is increased to about 300 g/L, the cobalt extraction rate is 100%. The extraction rate of nickel and chromium in the solution is only about 18%. In order to improve the separation effect of nickel and cobalt, the solution obtained by removing copper is concentrated to 1/3 of the original volume, thereby increasing the concentration of chloride ions in the solution to a suitable extraction degree. N235 (35%)-isooctanol (15%) monosulfonated kerosene (50%) organic phase at room temperature, in the organic phase: aqueous phase = 2:1, pH = 2, first-stage extraction Iron, 8 grade cobalt extraction, 0.2 mol/L hydrochloric acid grade 3 washed cobalt-rich organic phase, directly with 1 mol / L hydrochloric acid back extraction (iron inhibition in the organic phase) to obtain a pure cobalt solution. The extraction rate of iron from N235 increases as the acidity of the solution increases. 9%。 99. 93%. After the recovery of the nickel and cobalt, respectively, 99. 89%. 99. 93%. The content of Cu, Fe and Cr in the cobalt-rich organic phase is low, and it can be inhibited by high acid stripping in the organic phase. Co:Ni reaches 2315, and Ni:Co in the aqueous phase reaches 843. The raffinate aqueous phase can be directly concentrated and crystallized to produce industrial grade nickel sulfate. The cobalt-rich organic phase is back-extracted with 2 mol/L hydrochloric acid to obtain a pure cobalt solution, which can be further processed into a cobalt salt product or sent to electrolysis to produce 1# cobalt.
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