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Division 1.10.5 Metal emissions

United Kingdom

Original text. Later amendments are not shown.

TechniqueDescription
Selection of raw materials for the batch formulation with a low content of metalsThe technique consists of a careful selection of batch materials that may contain metals as impurities (e.g. external cullet), in order to reduce at source metal emissions which arise from the decomposition of these materials during the melting process
Minimising the use of metal compounds in the batch formulation, where colouring and decolourising of glass is needed, subject to consumer glass quality requirements

The minimisation of metal emissions from the melting process may be achieved as follows:

  • minimising the quantity of metal compounds in the batch formulation (e.g. iron, chromium, cobalt, copper, manganese compounds) in the production of coloured glasses

  • minimising the quantity of selenium compounds and cerium oxide used as decolourising agents for the production of clear glass

Minimising the use of selenium compounds in the batch formulation, through a suitable selection of the raw materials

The minimisation of selenium emissions from the melting process may be achieved by:

  • minimising/reducing the quantity of selenium in the batch formulation to the minimum commensurate with the product requirements

  • selecting selenium raw materials with a lower volatility, in order to reduce the volatilisation phenomena during the melting process

Application of a filtration systemDust abatement systems (bag filter and electrostatic precipitator) can reduce both dust and metal emissions since the emissions to air of metals from glass melting processes are largely contained in particulate form. However, for some metals presenting extremely volatile compounds (e.g. selenium) the removal efficiency may vary significantly with the filtration temperature
Dry or semi-dry scrubbing, in combination with a filtration systemGaseous metals can be substantially reduced by the use of a dry or semi-dry scrubbing technique with an alkaline reagent. The alkaline reagent reacts with the gaseous species to form a solid which has to be removed by filtration (bag filter or electrostatic precipitator)