Minerals and metallurgy

Oxidized titanium compounds are very common in nature; however, only rutile is used for the extraction, which contains 93-96% of titanium dioxide, which is extracted in the United States, Canada, Sweden and Norway, and ilmenite, which generally contains 44-70% of titanium dioxide, and is found in India, Siberia and Australia, also distributed as black sand on many beaches.
The most widespread industrial process for the preparation of titanium is the Kroll process (reduction of titanium chloride, prepared from rutile and ilmenite). A first chlorination operation of the mineral at 800 ° C leads to titanium tetrachloride. This is purified by distillation and then reduced with magnesium or sodium at 900 ° C in a helium atmosphere. The metal thus obtained is in powder or flakes (titanium sponge), and must be recast in a particular electric arc furnace in an argon atmosphere (VAR method, Vacuum Arc Remeltin) to obtain the ingot. From the ingot the various products are subsequently obtained, with traditional processes. Another method to obtain titanium is the electrolysis of titanium tetrachloride. However, the considerable amount of energy required for the transformation of titanium oxides, to reach the metallic state, significantly affects the final cost.
After the manufacturing process, titanium must be processed:
• In surface cleaning;
• With chemical passivation;
• Sterilization.

The ASTM specifications for the final treatment of the implants include immersion in molten salts with an alkaline base followed by etching with a solution of nitric and hydrofluoric acid. The intention is to eliminate contaminants such as iron, which demineralize the bone matrix.
Other processes can be used, such as sandblasting (Corundum) or the ionic process, the laser treatment, with relative advantages and disadvantages.
The final sterilization is now carried out on gamma rays, and most producers deliver the assembled implants in sterile tubes. This method represents a convenient and advantageous system.
Today protein deposits, the film of organic and pollution traces can best be treated with radiofrequency.
The direct recovery of a plant and the self-management of the sterilization cycle can best be done with a protocol for sterilization with ultraviolet rays, with great efficacy on spores and biological contaminants.