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The utilization of Reclaimed Asphalt (RA) in the road construction sector induces considerable economic and ecological benefits. The blending of the recycled material with new components is believed to be of great importance for the mixture’s properties. An extensive knowledge of the blending of the materials is crucial in optimizing the use of RA, especially at higher recycling rates. In this paper, the applicability of Fourier transform infrared (FTIR) microscopy in attenuated total reflectance (ATR) mode to study the bituminous coating of RA granulates is investigated. This method is a promising alternative to trace heterogeneous areas within the coating compared to methods that require extraction and recovery of bitumen. A method for sample preparation and FTIR spectra analysis is proposed. Four different samples were analyzed: a reference RA granulate, two types of RA granulates mixed with neat bitumen, and a RA granulate with rejuvenator. The results show that the use of ATR-FTIR microscope allows the tracing of different components, indications of blending, as well as proof of rejuvenation of the aged bituminous area.

This study investigates the feasibility of acid precipitation for the separation and recovery of lignin and hydrocarbon derivatives from the waste stream of the alkali extraction of recycled cardboard. The recovery of chemicals from this effluent is complex due to their heterogeneity. Apart from the lignin and hydrocarbon derivatives, also, fillers, inks, and polysaccharides are present. A procedure of fractional acid precipitation was designed, reducing the pH from 10.7 to 8.8, 7.2, 5.1, 3.1, and 1.5. Each solid fraction was analyzed by infrared spectroscopy to determine its chemical composition and amount of precipitate. A mixture of lignin and hydrocarbon derivatives was detected in the solids obtained at pH 3.1. A dichloromethane extraction of the hydrocarbon derivatives was performed. Both recovered lignin and hydrocarbon were analyzed by infrared and gel permeation chromatography. The lignin showed similar characteristics (e.g., molecular weight ≈ 10.000 Dalton) as commercial lignin from virgin softwood. For the hydrocarbon derivatives, a molecular weight range between 10000 Dalton and 150 Dalton was observed. In conclusion, this paper shows that the recovery of lignin and hydrocarbon derivatives is scientifically and technologically possible from the waste stream of the cardboard recycling processes. Further research is necessary to improve the extraction efficiency that was around 7.9% for the lignin and around 5.5% of the total amount of extractives compared to their amount in cardboard. Despite the low extraction efficiency, the estimated 9.6 million tons of lignin present in cardboard and the lignin price around 300-500 USD/ton make this research of industrial interest.

The study is a first investigation of the feasibility to preserve recycled fillers (e.g. calcium carbonate, kaolin) from deinking paper sludge for newspaper production using an alternative approach respect to the actual methods. Deinking paper sludge was incinerated at 575°C. The thermal stability of the incinerated sludge (ash) was evaluated by infrared analysis. Subsequently, the resulting ash was bleached by sodium dithionite. The particle size of the ashes was analysed by laser diffraction. The effect of recycled fillers on recycled paper pulp, after blending, was evaluated by the analysis of the physical and optical properties of the obtained paper sheets. Analysis showed the conservation of the calcium carbonate and other fillers' molecular structure, both after incineration of the sludge and after bleaching. The dithionite treatment of the ashes resulted in ISO brightness levels of more than 70. The brightness was stable over one month. Paper sheets made by blending the bleached ashes with recycled paper showed an improvement of brightness and opacity but a decrease in terms of porosity and breaking length compared to paper sheets made without any filler. The proposed method still requires further studies to evaluate the economical application but offers an opportunity for the recycling of inorganic materials and valorisation of the sludge.