Triboelectric charging and electrostatic separation of diverse, non-conductive mixed waste, especially plastic, employs enclosed vibro-conveyor followed by in-flight separation influenced by non-linear electrostatic field

摘要

The waste is reduced to particles. It is subjected to impacts, friction and mechanical shock between two uniformly-spaced surfaces. Positive and negative charging is achieved. Separation takes place in an electrostatic field. An Independent claim is included for corresponding plant. Preferred features: Particles are dosed judiciously into the process. Frequency, amplitude of impacts and cladding of the surfaces, are matched for the chemical composition of the waste. They are adjusted for maximum triboelectric charging. Strongly-charged particles are subjected to a field of controlled polarity and strength. Particles fly through electrostatically-adjustable paths to selection stations. Plant and its variations to carry out the process are described in considerable detail. This centers on an enclosed vibratory conveyor (D), which performs the electrostatic charging. Charged particles are carried away on a conveyor (E), from the end of which they leave, to be deflected into various bins, in accordance with their physical properties and charge. Their flight path is modified by a (known) rotary drum electrode, to which some particles adhere and are brushed off into a further bin.