Fulfilling environment protection and energy conservation tasks

Fulfilling Environment Protection and Energy Conservation Tasks in Management of Aerospace Industrial Wastes

O.M. Shapovalova, I.A. Markova, E.P. Babenko (Dnepropetrovsk State University).

The wastes of aerospace industry include ferrous and nonferrous alloys, glass-reinforced and carbon-fiber-reinforced composites, various nonmetallic materials, slurries, slags etc. and thus are extremely diverse in chemical composition, condition and properties. This necessitates a systems approach to their reuse.

A system for recycling these wastes was developed enabling fabrication of new, recycled composites through utilization of non-melting technologies.

The materials and modular waste-free processes thus devised offer following advantages:

safety and environmental friendliness,
energy conservation due to a 100-fold reduction in power consumption over conventional practices,
lowering the working area 10⁴-fold and the labor input 10⁵-fold,
a 10⁴-fold reduction in capital expenditures,
material composite structure resulting in combined functions of deoxidizers, inoculators, modifiers, desulfurazing and dephosporizing agents and master alloys for processing steels and alloys,
enhanced yields due to high specific surface, and
high-effective selective action on metal melts.

The commercial facilities for waste treatment in aerospace and related industries ensured an output of more than 4,000,000 t steel in 32 grades processed using the recycled composites.

These displayed following advantages:

enhanced deoxidizing capacity leading to a 3 to 5-fold reduction in oxygen levels compared to conventionally processed steels,
lowering sulfur and phosphorus in steel by 20 to 40 % and sinking the cold brittleness threshold by at least 50 %,
higher and more stable mechanical properties,
finer microstructure and enhanced morphology,
dramatic reduction in nonmetallic inclusions and their improved distribution and composition, and
primary grain refinement by a factor of 1.5 to 3.

Also developed and successfully tested were secondary alloys of titanium, aluminum, magnesium and iron and materials recycled from rocket thermal insulation.