The use of laser equipment to recover refractory materials can reduce 800,000 tons of carbon dioxide emissions

Refractory material can withstand high temperature above 1500℃. They are essential materials for industrial furnaces that produce glass or ceramics, non-ferrous metals and steel.

The service life of manufactured refractory products can range from a few days to many years, depending on the material, the temperature in the melting vessel and other operating parameters. As a result, although as much as 32 million tons of used refractory materials are produced worldwide each year, only a small fraction of this is recycled.

The production of refractories from primary feedstocks generates a considerable amount of CO2, mainly because CO2 must be removed from carbonate-type feedstocks. In addition, raw materials are mainly imported to Europe. There is currently no obvious alternative - and laser devices would be an excellent solution to this problem.

Automatic sorting by laser device

Alexander Leitner, resource project Coordinator at RHI Magnesita, explains: "Refractory products can be precisely adapted to customer requirements. The optimal composition of a high temperature resistant material depends on the intended application, the manufacturing process, and the associated chemical properties of the process medium. This means that our products have very different ingredients. So we have to separate them as precisely as possible before recycling them."

Therefore, the centrepiece of the project is an automatic sorting system for used refractory materials. The laser device will be used to identify the composition of the materials used on the conveyor belt without coming into contact with them. The Laser technology comes from Laser Analytical Systems & Automation (LSA) in Aachen, a spin-off company of the Fraunhofer ILT, which focuses on the development and production of real-time laser analysis systems for industrial applications.

"At Fraunhofer ILT, we have developed an online measurement technology that allows direct analysis of metal scrap on conveyor belts and detects the composition of each scrap." Dr. Cord Fricke-Begemann, head of the Materials Analysis group at Fraunhofer ILT, said, "With this multi-element analysis, we can detect a large number of alloys. We are now transferring these findings to refractories."

The research partners expect that as a result of the findings of this project, they can increase the potential recycling share of the industry from the previous 7% to 30-90%. "We are combining the latest analytics with state-of-the-art software to address current environmental concerns." We are on track to reduce CO2 emissions in Europe by 800,000 tonnes a year." Mr Cord Fricke-Begemann said.

A new method using laser as an underwater metal cutting tool

The demand for modern demolition techniques for underwater use is also growing. For example, to increase the generating capacity of offshore wind farms, old steel frames must first be removed below sea level and then rebuilt on a larger scale.

The Fraunhofer Institute for Materials and Beam Technology (IWS) in Dresden, Germany, has now found a technical way to use lasers as an efficient, environmentally friendly and energy efficient cutting tool in water.

To cut steel and other metals below the surface of the water, IWS researchers use a short-wavelength green laser that can cut even in water. At the same time, water acts as a tool to expel the resulting melt through the incision through pressure. This eliminates power loss, additional gas lines, and other drawbacks. In the lab, this has worked.

In September 2023, IWS will present this innovative process at the SchweiBen & Schneiden Welding and Cutting Exhibition in Essen, Germany.

Cutting metal with lasers is not a new method. However, it is usually operated in a dry environment - infrared or other fairly long lasers are used to cut metal after obtaining magnification benefits.

The IWS engineers used a green laser that has a much shorter wavelength than most current industrial lasers. However, this is possible because green lasers of more than 1kW class have become available to achieve the necessary cutting power.

In the future, a blue laser version with a shorter wavelength is also expected to be easily achieved. This short-wave laser can even penetrate water without causing major damage and loss, so it can also be used in water bodies. This medium, which is abundant in the ocean, can replace the cutting gas required in dry environments, thus eliminating the need for natural gas pipelines.

Source: OFweek