Latest investigations proved that foodstuffs packed in recycled cardboard packaging like cereals, flour, rice, noodles, and even chocolate from advent calendars may contain high amounts of mineral oil components which are suspected to pose risks to human health. These mineral oil components are mainly constituents of printing inks used in offset coldset processes. Due to their high volatility these substances are capable to migrate from the recycled packaging into foodstuffs at ambient temperature. In order to meet future limits for migration, investigations on mineral oil removal during stock preparation were carried out. To this end, a flotation process and two different heat treatment processes prior to pulping were investigated according to their ability to remove mineral oils. For flotation a correlation between removal of mineral oils and inorganic particles could be found for all process chemicals used in this study. By optimization of chemical concentration and dosing sequence up to 80 % of mineral oils could be removed while keeping the total losses smaller than 15 %. The heat treatment processes achieved mineral oil removal rates that were in some cases even higher than those for flotation. For these processes the most important parameters appeared to be the specific energy applied, the temperature, and the particle size distribution of recovered paper components. However, the specific energy consumption was quite high.
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