Sand Regeneration

Reusing resources – a core competence for the future

In times of continuously rising costs for old sand disposal, land-filling and new sand procurement, the topic of used sand regeneration is becoming an increasing focus of foundries in their efforts to maintain efficiency. In particular with the emerging shortage of landfill sites and changing legal framework conditions, the disposal of used sand is becoming increasingly complicated.

HWS is setting new benchmarks with the new product range of type USR-II for the mechanical regeneration of used sand as green sand and organically bonded core sand.

  • The process

    The type USR-II mechanical regeneration system for used sand operates with the method of removing the casing shells with a particularly gentle friction process from grain to grain. This results in a basic moulding material, similar to new sand, that is suitable for reuse.

    With this, removal of the used casing shells is only the “core element” of the overall process of mechanical regeneration. This usually encompasses the following steps:

    Bentonite-bonded mould sand and organically bonded core sands, as well as pure green sand can be efficiently and gently regenerated with the USR-II.

  • The principle

    The active principle of friction is used to remove the binder residue from the sand grains. This is generated by rotating the sand in a drum and applying the necessary pressure to the sand via ceramic pressure rollers. Thanks to the variable contact pressure, the active principle can be individually tailored to the sand characteristics of our customers. The binder residue is rubbed off, grain by grain. This principle is the most gentle variant of mechanical regeneration and results in a very high reclaimed product yield (ratio of regenerated sand to the input quality of used sand) with very good cleaning results.

    The following are important signal components for the degree of regeneration with:

    1) Bentonite-bonded sands:
    Loss on ignition, active clay content, slurry, pH value, electrical conductivity

    2) Organically bonded core sands:
    Loss on ignition, slurry, pH value, electrical conductivity

  • The advantages

    • Efficiency (new sand – landfill – binder content)
    • Environmental protection – recycling economy – conservation of resources
    • Improved grain form – grain rounding
    • Smoothing of the surfaces
    • Removal of fine portions or dust (old binder constituents, etc.)
    • Lower costs (initial and ongoing costs) than with thermal or thermal-mechanic regeneration
    • No special environmental requirements (see thermal regeneration: exhaust gas, CO2, etc.)
    • No continuous operation required (no long heat-up times, etc.)
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