Neutralizace kyselých složek odpadních plynů s pomocí metalurgických odprašků

Abstract

In recent years, amount of waste PVC have rapidly increased due to the end of the life cycle of long life PVC products, produced since the beginning of a massive expansion of PVC in the middle of the last century. Rather different waste material is metallurgical dust of landfilled. It is a hazardous waste due to high content of zinc and other heavy metals. The work is focused on reducing the amount of PVC waste by pyrolysis in presence of the steelmaking dust. The idea was to convert of organically bound chlorine into inorganic salts, which can prevent formation of chlorinated dioxins and similar toxic substances. Possibility to gain metal materials as a byproduct may be the other goal of the process. Pyrolysis of PVC was investigated studying its destruction and release of hydrogen chloride. Then, efficiency of chlorine capture was determined by PVC co-pyrolysis with metallurgy dust. The dust under investigation was taken as an averaged refuse of the steel-making plant. The results of experiments show good sorption and neutralization potential of the dust to capture the hydrogen chloride in nascent state. Moreover, all the formed hydrogen chloride has been transferred to inorganic salts, 92% of them being water soluble. From the viewpoint of the metal separation, it is primarily the zinc chloride, which can be leached along with minor heavy metal chlorides. The insoluble solid phase dust residuum is enriched by iron oxides and some carbonaceous pyrolysis product. Unfortunately, iron and zinc cannot be completely separated under by the one-step process. Greater amounts of zinc is transferred into the soluble form at lower temperatures, however it occurs for iron as well. To conclude, the presented study demonstrates feasibility of the process of chlorine abatement and simultaneous zinc gain from a couple of dangerous waste materials. Some proposals for following research leading to further potential improvements of the suggested technology are outlined.