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Welcome to Virtual Curtain

VCL has worked with CSIRO since 2008 to provide long term solutions for the remediation and neutralisation of above and below surface acidic and contaminated geochemically-complex wastewaters from mining and industry to a quality suitable for reuse or for discharge into the natural environment.

The treatment (licensed by CSIRO to VCL) involves the synthesis and application of hydrotalcites – a layered double hydroxide mineral, primarily composed of magnesium and aluminium.

Simple, generally one-step application methodology suitable for:

  • In-situ, one-off treatment of large contaminated open-pit lakes
  • Batch treatment (“pump and treat”) of contaminated open-pit lakes using satellite pits
  • “In circuit” treatment and remediation of process plant waste water
  • Sub-surface treatment of contaminated aquifers by injecting a “virtual curtain” of reagents to interact with and neutralise groundwater plume

The technology has world-wide application for:

  • New mining/industrial projects which are subject to increasingly stringent environmental operating and project closure licences
  • existing mining and industrial projects which produce acidic and/or contaminated wastewater
Advantages of hydrotalcite technology

Virtual Curtain technology offers superior outcomes to the traditional use of lime-based additives to remediate acidic and contaminated waste water, with advantages including:

  • Typically one-step process with simultaneous removal of anions and cations and significantly reduced sludge volumes, by up to 90 per cent compared with lime-based precipitated sludges.
  • Additives can be dissolved for solution-solution mixing with rapid reaction kinetics (less than one minute to form) and rapid de-watering.
  • Hydrotalcites can be formed from acid, neutral, and alkaline waters, and from fresh to (hyper)saline waters, so have a wide range of applications.
  • Hydrotalcites form rapidly using commercially available reagents.  Rapid settling and dewatering means that a large proportion of the treated water is immediately available for reuse or discharge.  In contrast to lime, the smaller precipitate volumes and higher solids content means dewatering is generally unnecessary.  This also means less materials handling and smaller final/disposal void requirements compared to lime.  A Na-dominated cation chemistry and the removal of particulates, colloids, and most foulants including Al, Fe and Si mean that the technology can also be used as a pre-treatment for Reverse Osmosis (“RO”) to enhance operational efficiency.
  • Hydrotalcite precipitates encapsulate high concentrations of uranium, rare earth element, copper and other valuable metals (200-500 times enrichment), often at ore grade, which can be reprocessed to offset remediation costs.
  • Hydrotalcites can be further stabilized via calcining to form spinel or silicified to produce a synthetic chlorite analogue for permanent storage for a range of radionuclides liberated during or after cessation of uranium mining.