The invention discloses a method for preparing electronic-grade
nickel sulfate from
nickel powder, a
crystallization device and a control method of the
crystallization device, and relates to the technical field of non-
ferrous metal hydrometallurgy. The method comprises the steps of oxidation, cooling, acid leaching,
copper removal, acid adjustment, concentration, cooling
crystallization,
drying and screening, and secondary leaching, and is characterized in that in the oxidation step, the temperature of
nickel powder in a calcining furnace is controlled to be 400-700 DEG C, the use amount of
compressed air for each
kilogram of nickel
powder is 1-5 m3, and the reaction is carried out for 1.0-2.5 hours; the acid leaching comprises the following steps: putting the cooled
nickel oxide in a reactor, controlling the temperature to be 45-70 DEG C, adding dilute
sulfuric acid to control the pH value to be 0.5-1.5, and reacting for 1-3 hours. The invention also provides a crystallization device and a control method of the crystallization device. According to the method,
metal nickel can be oxidized into
divalent nickel oxide,
hydrogen cannot be released when acid is added for
dissolution, a large number of oxidizing agents do not need to be additionally added, new
impurity ions are not added in the process, the nickel
ion concentration is relatively improved, and nickel
sulfate crystal particles are uniform.