Co²⁺ + 2 OH⁻ → Co(OH)₂(s)Simplified assessment of dcobalt(II) hydroxide training.
Use when: Other species and oxidation states can occur in a real process.
Cobalt recovery by precipitation
Link pH, solubility and coprecipitation in a metalliferous solution.
What is happening?
Precipitation transforms a dissolved species into a poorly soluble solid. For a hydroxide, increasing the activity of the hydroxide ions can make the solution supersaturated.
Precipitation pH depends on concentration, complexes and impurities. A cobalt-rich precipitate can still retain solution or incorporate other elements; recovery and purity must be monitored separately.
The formulas, with their conditions.
Kₛ = a(Co²⁺) × a(OH⁻)²Dimensionless activities.
Use when: In equilibrium with the corresponding solid; supersaturation is judged with the ionic quotient.
Where is this principle used?
Cobalt factory
Form a hydroxide intermediate before refining.
Treatment of metal effluents
Reduce certain concentrations of dissolved metals.
What to observe in the experiment
Gradually increase the scenario pH and compare the quantity of cobalt recovered and the impurity content of the precipitate.
References and readings
This sheet explains the principles and their assumptions. Educational simulation can simplify the process; an industrial model requires suitable data and validation.
Have you understood the essentials?
Only one correct answer per question. Answer all three questions, then view the answer key.
Intu Lab · Understanding sheet · Kimba Christian