Nickel is recovered through extractive metallurgy .
Concentration is done by froth floatation
Next stage is roasting and reduction of the sulphide ore which yields 75% pure nickel
Refining is done by “Monds Process”
Nickel is reacted with carbon monoxide at around 50 °C to form volatile nickel carbonyl . Any impurities remain solid while the nickel carbonyl gas passes into a large chamber at high temperatures in which tens of thousands of nickel spheres, called pellets, are constantly stirred. The nickel carbonyl decomposes, depositing pure nickel onto the nickel spheres. Alternatively, the nickel carbonyl may be decomposed in a smaller chamber at 230 °C to create fine nickel powder. The resultant carbon monoxide is re-circulated through the process. The highly pure nickel produced by this process is known as carbonyl nickel.
The crystal structure of titanium at ambient temperature and pressure is close-packed hexagonal α phase . At about 890°C, the titanium undergoes an allotropic transformation to a body-centred cubic β phase which remains stable to the melting temperature.
Some alloying elements raise the alpha-to-beta transition temperature (i.e. alpha stabilizers) while others lower the transition temperature (i.e. beta stabilizers).
Aluminium, gallium, germanium, carbon, oxygen and nitrogen are alpha stabilizers.
Molybdenum, vanadium, tantalum, niobium, manganese, iron,chromium, cobalt, nickel ,copper and silicon are beta stabilizers.
Alpha alloys which contain neutral alloying elements (such as tin ) and/ or alpha stabilisers (such as aluminium or oxygen ) only. These are not heat treatable.
Near-alpha alloys contain small amount of ductile beta-phase. Besides alpha-phase stabilisers, near-alpha alloys are alloyed with 1-2% of beta phase stabilizers such as molybdenum , silicon or vanadium.
Alpha & Beta Alloys , which are metastable and generally include some combination of both alpha and beta stabilisers, and which can be heat treated.
Beta Alloys , which are metastable and which contain sufficient beta stabilisers (such as molybdenum, silicon and vanadium to allow them to maintain the beta phase when quenched, and which can also be solution treated and aged to improve strength.
Engine parts such as connecting rods, wrist pins, valves, valve retainers and springs, rocker arms and camshafts, to name a few, lend themselves to fabrication from titanium, because it is durable, strong, lightweight and resists heat and corrosion.