Engineering Headlines

Billions of expensive waste soon comes to an end!


Researchers from Aachen have developed a process that makes them recyclable precious metal scrap.

The pollution with oxygen they fight with calcium. The so-called simple lime is separated off.

Airbus has more than 700 orders for its latest A350 aircraft. Around two dozen have already been delivered.

During the production of the blades for the powerful turbines, 100,000 tonnes of scrap remain, which can only be converted into titanium dioxide, which ensures brilliant white in colors.

Melting, in order to be able to use it again for blade production, is not yet possible because the material is contaminated by cooling liquid and is also oxidized.

The waste, if it could be used again for the production of shovels, would have a value of three billion euros.

Scrap melts at hellish 1600 ° C

In the future, the supposed scrap is worthwhile again.

Researchers at the Institute for Metallurgical Process Engineering and Metal Recycling (IME) at Aachen University of Technology have developed a recycling process that produces titanium blocks from which new turbine blades can be milled or cast.

“We have solved the crucial problem that makes recycling impossible so far,” says Professor Bernd Friedrich, who heads the institute.

This problem is called oxygen. Titanium scrap oxidises immediately when it comes into contact with air. This oxygen must be removed. “We did that,” says Friedrich.

The washed scrap lands in an induction furnace. At 1600 ° C it becomes liquid.

The oxygen escapes partially, but in large part it remains in the melt. It is bound by calcium, which is poured into the furnace. This produces calcium oxide, better known as lime.

It floats on the melt so that lime and titanium can be separated.

Recycling of scooped vanes

The second problem is not yet resolved. The scrap contains metal particles that have separated from the processing tools. The contaminated titanium alloy is re-melted.

The liquid “souvenirs”, Friedrich explains, are separated by a seal separation.

Titanium blocks remain, from which new blades can be made.

The process is also suitable for the recycling of complete shovels, which have served after a maximum of 20,000 flight hours.

First, the ceramic layer surrounding the blades to protect against oxidation is removed.Then they land as well as scrap in the induction furnace.

Currently, the researchers are preparing the industrialization of the process.One in five commercial aircraft is sent to the desert for parking.

Temporary or permanently no longer needed commercial aircraft at airports is extremely expensive.

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