Hello all dear
The shear mechanism is mentioned on this site, can anyone explain more?
https://www.recyclingtoday.com/article/system-extracts-pigments-from-mixed-plastic-scrap/
Thanks in advance
The process described involves the extractive removal of pigment particles from plastic (solid-liquid extraction). This is a diffusion-driven process in which the pigment diffuses into the solvent. To increase the intensity, we need a large contact area between the solid particles (shredded plastic) and the liquid extractant (e.g. xylene). Using high shear forces (“shear mechanism”), the liquid phase can be finely distributed (crushed, emulsified), creating a large surface area (phase area, contact area), which promotes mass transfer.
What “shear mechanism” has in common here is that the liquid phase is exposed to high shear forces (= high flow speed in narrow cross sections, sharp deflection of the flow, deflection of the flow direction, high turbulence, etc.) e.g. in the extruder, emulsifier unit, two or more counters -rotating rollers, a baffled oscillation separation system or a shredder etc. In addition to diffusion, the high flow velocity increases mass transport and ensures permanent renewal of the phase interface.
The term “shear mechanism” was certainly used here for patent law reasons in order to claim the patent claim for as many apparatus solutions as possible, just in case something was forgotten or overlooked when listing.
Here are some references related to shear mechanisms in plastic recycling:
Please note that these references cover various aspects of shear mechanisms in plastic recycling and can provide you with more detailed information on the subject.
Article Solid-State Shear Milling for Recycling Aluminum–Plastic Pac...
https://verra.org/wp-content/uploads/2020/02/Terms-of-Reference-for-the-Plastic-Standard-29-JULY-2020-formatted-version.pdf
https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-34874.pdf
https://www.mdpi.com/2071-1050/15/7/6144/review_report
Good luck
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