Lignite is a soft brown fuel with characteristics that put it somewhere between coal and peat. It contains more moisture than coal but, when dried, it crumbles easily.
Sand and gravel contaminated by lignite is not suitable for use in several markets, particularly concrete sand and building sand. Concrete producers will only use sand the meets the ‘Standard Specification for Concrete Aggregates' of less than 0.5% (although this can vary between applications). This has had a major impact on the market value of lignite-affected sand in regions where lignite is common.
Due to Lignite's brittleness it breaks down during the washing process to small sizes and is often dealt with during the sand washing stage, however in some areas where large pieces of lignite are present it must also be removed from the gravel fraction. The removal of Lignite provides an uncontaminated sand and gravel for further processing. Duo offer complete turn key systems for the removal of lignite from both sand and gravel. Our systems are tried and tested and bespoke for each to each application.