Particulate emissions in the flue gas of flat glass production after electrostatic precipitators

Abstract

As a contribution to the current discussion about fine dust and fine quartz and cristobalite particulate emissions and immissions, the authors point out the role the flat glass industry plays in this context. The main part of the raw material used in this industry is quartz sand (about 60 %), but the latter's granulometry is such that it contains practically no fine particles. This fact is inherent in undisturbed glass production because quartz sand particles with grain size below 80 μm would cause bad glass quality. Also other possible sources for silicon dioxide in the flue gas are discussed. In order to show the composition of the dust escaped to the electrostatic precipitators (EPs), the filters exclusively used in flat glass production, a number of quartz glass fiber filters used to measure the dust content in various plants were analyzed by X-ray diffraction and scanning electron microscopy. Only in one case a quartz or cristobalite grain was identified, but with 30 μm it was bigger than the respiratory fraction (< 10 μm) under discussion. In summary, it can be said that the findings are not at all alarming. In order to finally prove that there is no need to worry about emissions of carcinogenic dust for the whole glass industry future cooperative research will be necessary.