FINEST Mineral Additives

Introduction

Sub-project 2 develops and demonstrates mixed mineral/plastic waste recycling value chains by combining pyrolysis of mechanically pretreated demolition ETICS with minerals calcination to maximize both, utilization of organic and inorganic as secondary industrial feedstock. Main achievement is a ready-to-transfer demonstration of the generic value chain at TRL 5 level, making use of the pyrolysis pilot plant and the new “R-Zement” calcination pilot plant at KIT. We will evaluate toxicological risk of waste feedstocks, intermediate and recycled materials and develop a networked concept for waste ETICS.

With an annual use of approx. 7,5 Mt fine and ultra-fine mineral additives in plastics account for approx. 2 % of the global plastics production (380 Mt., [28]). Mineral additives are frequently used as fillers to lower the consumption of polymers. Increasingly important is their ability to improve chemical and physical properties (e.g. reinforcement, pigments, etc., [32], Table 4) and the tendency to produce nano-enabled plastics, which are based on nanometer sized particles like carbon nano-tubes, Fe2O3 or TiO2 [76]). Furthermore, finely distributed inorganic components are generated from plastic waste, for example during thermal conversion of metal-containing organic additives such as heat stabilisers or polymers that contain chlorine and bromine.

Scientific approach and required competencies

The research addresses the management of material flows from different mixed plastic wastes in chemical recycling including the adhering and incorporated additives and accompanying substances. For this purpose, the project is structured in 6 work packages (WPs). At first, Finest Mineral Additives in mixed plastic wastes (WP1) investigates the occurrence of mineral fines qualitatively and quantitatively from literature data as well as analytically from real samples. The (potential) relevance of specific wastes is evaluated based on toxicity, dissemination into the environment, quality change of product and waste streams, process effects, quantities, conventional disposal effort, etc. Waste streams including mineral additives with high relevance are additionally investigated in depth in WP 2 to 6. WP2, sensor technology selects suitable sensors for input control, sorting, process control, monitoring, and quality assurance of a decentralized recycling plant together with potential industrial partners (manufacturers, recycling industry, plant constructors, B2B customers).

WP3, Pyrolysis of mixed plastic waste investigates reactions and kinetics during pyrolysis of wastes from different sources containing finest mineral additives. It will determine the final partitioning of the additives including particle generation and consumption in the off-gas (synthesis gas), liquid, and solid fractions. WP4 Inertisation of fines in clinker processing uses fines from pre-sorting and pyrolysis waste streams in cement/belite processing. Experimental trials and analytical approaches are complemented with digital models. Main focus is the determination of capacity limits and the influ-ence on the products. Particle flows relevant to the environment or health in gas streams WP5 examines gas streams in the pyrolysis and cement process as basis to design the necessary gas cleaning steps for a higher TRL. Finally, WP6 Assessment of local/decentral and integrated plastics and mineral fines recycling investigates the techno-economic and environmental aspects of FINEST removal technologies (WP2-WP5) and develops a networked concept for the decentralised management of mineral fines in chemical recycling. This concept is integrated into an overall concept for decentralised recycling.