METALS AND METALLURYG

SYLLABUS

➧ Occurrence of metals in nature :• Mineral and ore-Meaning only.• Common ores of iron, aluminium and zinc.➧ Stages involved in the extraction of metals :(a) Dressing of the ore-hydrolytic method, magnetic separation, froth floatation method.(b) Conversion of concentrated ore to its oxide-roasting and calcination (definition, examples and equations).(c) Reduction of metallic oxides-some can be reduced by hydrogen, carbon and carbon monoxide (e.g., copper oxide, lead (II) oxide, iron (III) oxide and zinc oxide) and some cannot (e.g., Al2O3, MgO) - refer to activity series. Active metals by electrolysis e.g., sodium potassium and calcium (reference only).Equations with conditions should be given.(d) Electro refining-reference only.➧ Extraction of Aluminium.(a) Chemical method for purifying bauxite by using NaOH-Baeyer’s Process.(b) Electrolytic extraction - Hall Heroult’s process :Structure of electrolytic cell- the various components as part of the electrolyte, electrodes and electrode reactions.Description of the changes occurring, purpose of the substances used and the main reactions with their equations.➧ Alloys-composition and uses :Stainless steel, duralumin, brass, bronze, fuse metal/solder.