VARISORT+ CARBON BLACK: Fully Functional MWIR Sorting System
From virtual presentation to fully operational system: At the end of June, Sesotec transferred the first VARISORT+ CARBON BLACK sorting system from production to its in-house technical center, where it can now test various customer applications. The high demand for the new system has exceeded expectations, and all efforts are now focused on the immediate execution of product tests.
With the VARISORT+ CARBON BLACK, Sesotec bridges one of the last technological gaps in optical plastic sorting. This system detects black plastic parts at a relatively coarse grain size after pre-shredding and reliably sorts them by material type—before the final grinding into fine granulate. Previously, sorting black plastics was often only possible at much smaller grain sizes during the granulate stage. This meant material separation occurred later in the process, requiring significantly more sorting effort.
At the heart of our innovation is Mid-Wave Infrared Technology (MWIR), which allows Sesotec to strategically expand its sensor portfolio into the wavelength range essential for reliably detecting carbon-black-containing plastics. While black plastics largely absorb visible light and the Near-Infrared range (NIR), making them difficult for conventional optical systems to detect, they exhibit distinctive spectral signatures in the MWIR range. This enables precise material classification.
The material is illuminated with mid-wavelength radiation. An MWIR sensor captures the material-specific spectra, which are then analyzed using intelligent software, established AI models, and Sesotec's extensive expertise in spectral analysis. This enables reliable differentiation of plastic types such as PE, PP, or ABS—even with highly absorbent carbon-black-containing plastics.
The key advantage of this technology is its seamless integration into the existing Sesotec platform. Users can continue to leverage proven software, algorithms, and AI models, ensuring high classification accuracy with minimal implementation effort.
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“By transferring the system to our technical center, we've reached a crucial milestone,” says Tobias Eder, Head of Technologies Sorting & Plastics at Sesotec.
“The feedback at IFAT highlighted the significant demand for a reliable solution to sort black plastics. With the combination of MWIR technology, intelligent software, and our extensive experience in spectral analysis, we can tackle this challenge early in the recycling process.
Once integration is complete, we will deploy the system with our customers under real-world conditions and fine-tune it based on practical insights to perfectly suit each application.”
The VARISORT+ CARBON BLACK is now entering practical trials in our technical center under realistic conditions. Customers can test their own material streams and evaluate the system's performance for their specific applications. Insights gained from these trials will drive further optimization. With VARISORT+ CARBON BLACK, Sesotec expands its portfolio with a key technology for high-quality plastic recycling, making a significant contribution to closing material loops.