Pulverization of end-of-life tires by ultra-high pressure water jet process

Abstract

<jats:title>Abstract</jats:title> <jats:p>Crumb rubber (CR), as a final product from end-of-life tires through size reduction process, has proved an appropriate end product for accumulated discard waste tires all around the world. Unlike pre-existing pulverization methods, such as ambient or cryogenic grinding and solid-state shear extrusion, an entire cool pulverization process utilizing ultra-high pressure water jet (UHPWJ) was proposed in this paper. Pulverization experiments under various processing parameters were designed and conducted. The particle size distributions of produced CR were obtained using laser particle analyzer. Microscopic morphologies of CR and rubber fracture surface were observed under scanning electron microscopy. The crosslink density and gel fraction of produced CR were experimentally determined. Influence of four main processing parameters as pump pressure, transverse velocity, standoff distance and impacting angle was discussed in detail, and the most suitable processing parameters were recommended. The results show that the particle size distribution of produced CR with UHPWJ is between 45 μm and 200 μm, and the surface of CR is coarse and porous. High compressive shear effect and erosion are the main mechanisms in UHPWJ pulverization. Besides, the produced CR has already been partly devulcanized after UHPWJ pulverization, and polymer degradation occurred in the meanwhile.</jats:p>

Mechanochemical devulcanization of waste tire rubber in high pressure water jet pulverization

“…The qualitative analysis on the flow filed of HPWJ was conducted under different working pressures within 140–220 MPa. 32 The experimental setup is given in Table 2. The modification performances of GTR in asphalts were evaluated by comparison experiments.…”

“…31 Previous studies had showed that WJPul process is a fine WTR pulverization method, and both rubber depolymerization and devulcanization can be detected during the WJPul process. 25,32,33 However, the interactions between HPWJ and WTR are not well understood yet, and the devulcanization mechanisms of WTR in WJPul remain still undefined, which are just the focuses of this work.…”

Recent Advances in Development of Waste-Based Polymer Materials: A Review

“…Wang et al [240,241] investigated the quality of GTR (e.g., particle size distribution; average particle size; cross-link density) and sol fraction as a function of water-jet pulverization parameters. The results showed that the average particle size of GTR obtained by water-jet pulverization was below 200 µm, while the microstructure of GTR indicates that high compressive shear forces acting on cross-linked rubber during water-jet treatment might result in partial reclaiming on the GTR surface.…”