Titanium life in titanium hands: advanced use and reuse.

PROJECT DESCRIPTION

BACKGROUND

Metal recycling plays an important role in manufacturing activities, providing environmental benefits in terms of energy saving, reduced greenhouse gas emissions and reduced waste volumes. Manufacturing activities attempt to reduce the related costs and shorten the recycled metal supply chain. In the case of titanium, recycling is even more important, because the current titanium extractive metallurgy process, leading to titanium sponge, is extremely labour-, energy- and capital-intensive. Moreover, subsequent crushing and repeated melting of the sponge is necessary to remove inclusions and reach the required level of uniformity. Therefore, the multiple steps of the primary metallurgical processes mean that titanium-embodied energy is relatively high compared to that of other commonly-occurring metals.

OBJECTIVES

The LIFE for life's material project aims to develop and test two innovative technologies: cryogenic machining and spark plasma sintering (SPS). Either technique alone would not allow reprocessing or recovery of titanium chips on site, but used in conjunction they open the way for a completely new approach to machining and closed cycles with zero waste production. The project will thus combine the two technologies to develop a small demonstration line for complete and direct recycling of titanium chips, and the chip removal process (about 1 500 kg/year). The process entails lower temperature and low thermal conductivity, meaning longer useful life of cutting tools and higher machining speeds for greater energy efficiency. By using liquid nitrogen instead of lubricant oil, high-quality grade 5 titanium pieces will be produced, titanium chips will not be superficially polluted by oils, and the final product will be protected against oxidation.

Expected results:

Complete elimination of the use of lubricants and lubricating/cooling oils or their emulsions in titanium grade 5 machining. Currently, the estimated consumption of lubricating/cooling oil is 2 000 Kg/year;

Longer useful life of cutting tools by up to 40% in the case of turning or by 260% in the case of milling. This will result in less waste and a lower level of contamination of the titanium chips processed;

Full recycling of titanium swarf that is no longer contaminated by organic lubricant/coolant, for an annual amount of 1 500 kg, without any treatment prior to sintering;

Energy consumption reduced by 40-60% compared to remelting in a vacuum induction furnace;

Elimination of the need to clean the titanium chips (no use of soaps, detergents and pickling acids) or the machined components, as liquid nitrogen just evaporates into the air without polluting;

Development of lighter and innovative high-performance components;

Production of titanium components at a lower cost compared to those obtained by processing bars or by casting; and

Elimination of the costs of disposal of titanium swarf contaminated by lubricant and coolant.