In the next of our series covering the heavy minerals contained in the Fingerboards mineral sands deposit, we focus on titanium – the ninth most abundant element in the earth’s crust and the fourth most abundant metallic element.
Titanium is found in the minerals rutile, ilmenite and leucoxene. Almost every igneous rock contains these titanium-bearing minerals. Like quartz, these minerals are physically and chemically inert, meaning they survive the earth’s weathering process well. Both ilmenite and rutile are abundant in the ancient beach which is the Fingerboards deposit.
Forty percent of the world’s rutile is sourced from Australia and half of that resource occurs in Victoria. Australia hosts 19 percent of global ilmenite resources and more than 20 percent of that occurs in Victoria.
Rutile and ilmenite are refined into titanium dioxide (80 percent of the world’s market) or titanium metal (the remaining 20 percent of the world’s market). Titanium dioxide is an ingredient in products rather than a primary material.
Titanium dioxide is produced by oxidising ilmenite or other titanium minerals at high temperatures. It is then ground into the fine powder required for its many uses, the most common of which is as a whitening, brightening and opacifying agent.
Common in paints, it’s used as a whitening pigment (replacing lead) and to increase reflectivity. The same properties make it useful in sunscreen as it refracts light and absorbs ultraviolet rays. Titanium dioxide is also commonly used in high quality paper, rubber, plastics, cosmetics and toothpaste, and increasingly being used as a food additive (E171) to whiten products or make them look more opaque - chewing gum, skim milk, marshmallows, lollies (such as Smarties) and supplements are some examples.
Titanium metal is known for its strength and weight (as strong as steel and less than half its weight), resistance to rust, and a high melting point. Titanium combines with iron, aluminium, vanadium, nickel, molybdenum and other metals to produce high performance alloys. It is used in jewellery, sporting equipment (tennis rackets, goalie masks, golf clubs, bicycle frames), surgical tools, scissors, and mobile phones. Other high-performance products containing titanium include jet engines, spacecraft, military equipment, bearings, and body armour. A Boeing 737 Dreamliner is made of 15 percent titanium.
Due to its biocompatibility, titanium is widely used in medicine, particularly as implants to replace or stabilise broken bone. Hips and knees are common examples, plus pacemaker cases, dental implants, craniofacial plates and Cochlear implants.