Chemical precipitation

Elina Merta, VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Finland, elina.merta(at)vtt.fi

Chemical precipitation techniques can be used to solve a number of problems in mine water treatment. Precipitation and co-precipitation are applicable for the removal of metals as hydroxides, carbonates or sulphides. Precipitation techniques are available also for the removal of sulphate. Conventional alkaline treatment where metals are mainly precipitated as hydroxides is evaluated separately.

The following Closedure articles describe in detail various chemical precipitation techniques targeting at the removal of metals, sulphate or arsenic and selenium:

Removal of metals:

• Sulphide precipitation

Sulphate removal techniques:

• Precipitation with barium salts
• Ettringite precipitation

Removal of As and/or Se:

• Iron co-precipitation