The vacuum-thermal demercurisation process
The vacuum-thermal processing used in demercurisation requires a sealed enclosure in charging operation. The mercury held within the waste is then evaporated at temperatures ranging between 340°C and 650°C and pressures of just a few millibar, and recovered in crude form after condensation at lower temperatures. Organic components are oxidized as required in an oxygen-rich burning chamber at temperatures ranging from 800°C to 1000°C. The residue which remains at the end of the vacuum-thermal process is essentially mercury-free and depending on its composition is either recycled or disposed of safety. The crude mercury recovered is then refined to the highest quality via a multi-stage cleaning process and brought to market.
New special technology for sludge treatment
In 2002 the GMR introduced a new developed vacuum recycling plant for the demercurisation of residues and naturally radioactive slurries containing mercury taken from the natural gas industry. This plant provides dust free treatment of these waste products through the entire process. As they have been designed for mobility, they can also be operated by clients locally. The plant works in charging operation with a capacity of approximately 1 t/d. The demercurisation takes place in a vacuum sealed, double wall heated mixer, using thermal oil with a maximum temperature of 340 °C as the heating medium. For dust separation a high efficient vapour filter is used. Via fractional distillation separate recovery of water and contaminated samples (hydrocarbons/mercury) is possible. The cooling/conditioning of the demercurisated residue then takes place in an integrated cooling mixer connected via vacuum to the heating mixer. For the withdrawal of the mineral residues a discharge screw is used. The intensive mixing during distillation guaranties an optimal energy exchange and provides short energy saving processes.
Representation of the process