21-Mat-B2 Pyrometallurgy, May 2015: worked solutions

Paper format. National Exams, May 2015 — 10-Met-B2, Hydrometallurgy and Electrometallurgy. Three hours, closed book, approved Casio/Sharp calculator only. Six numbered Problems, each worth 20 marks: Problems 1 and 2 are compulsory; the rubric asks for any 3 of the remaining 4 (Problems 3-6). All six Problems are answered below.

Note on the exam title

Nothing on the paper is a pyrometallurgy (roasting, smelting) question; the syllabus actually examined is aqueous leaching, solubility/Eh-pH (Pourbaix) diagrams, electrowinning thermodynamics, and hydrometallurgical flowsheeting.

Reference texts. The answers below are keyed to the works normally recommended for this syllabus code:

F. Habashi, A Textbook of Hydrometallurgy, 2nd ed. — leaching, solubility/speciation diagrams, solvent extraction, ion exchange, cementation and precipitation, electrowinning and electrorefining.
M. L. Free, Hydrometallurgy: Fundamentals and Applications, 1st ed. — Eh-pH (Pourbaix) diagram construction and reading, aqueous speciation, electrochemical cell design.
T. Rosenqvist, Principles of Extractive Metallurgy, 2nd ed. — general extractive-metallurgy context and process flowsheeting.

21-Mat-B2 Pyrometallurgy: May 2015