Description: Das Projekt "ECSC-WORKENV 5C, Direct recycling of zinc-contaminated LD filter dusts and slurries" wird/wurde gefördert durch: Kommission der Europäischen Gemeinschaften Brüssel. Es wird/wurde ausgeführt durch: Krupp Hoesch Stahl.Objective: The aim of the research is to return a greater proportion of LD than currently achieved directly, i.e. without prior thermal or other processing in special units, to the steel making process by introducing time-controlled separation. This would substantially reduce the cost of processing the remaining zinc-contaminated fines of the LD, as the quantity would be reduced. Although in theory (mainly thermal) processes are already available, at least as prototypes, for the processing of zinc-contaminated and dusts, the energy input and cost of such processes is enormous. A significant reduction in the quantities of LD which cannot by recycled directly therefore contributes to a reduction in the cost of this steel production process and hence to greater competitiveness and reduced pollution. General Information: In preliminary investigations the primary dust collection system was first examined qualitatively and quantitatively in order to establish the pre-requisites in terms of sampling location, sample quantity and sample number for targeted, systematic operational tests. The solids loading of the wet-cleaned converter dust was examined mechanically and chemically in respect of quantity, consistency and discharge behaviour over time. A fast zinc discharge rate of a dynamic nature preceding the discharge of dust was found. Quantitative sampling was successfully tested using a known zinc input quantity. The discharge behaviour of the dusts entering the secondary dust collection system was examined subsequently. The aim here was to investigate whether a process-dependent discharge rate could be identified, particularly for zinc, which inhibits recycling. This would make it possible to separate out dust fractions from the secondary dust collection system over the course of the process independently of the sludges from primary dedusting. Achievements: Monitoring over time of the zinc contents in the converter primary dust over the course of several heats revealed that even with average zinc quantities of 100 kg per heat, which is 50 per cent higher than today's average zinc input in charge scrap, separation of utilizable sludge fractions by purely mechanical means is possible if: - in the making of high-quality steels using blue scrap (zinc-free) the entire dust discharge is utilizable, - using low-zinc mixed scrap, timed separation into a 2/3 high-Zn and a 1/3 low-Zn utilizable sludge fraction is feasible. When using high-zinc old scrap suspected of containing alloying elements the entire dust charge, including the low-zinc fraction, was always higher than 0.4 per cent Zn and therefore not suitable for use in our sinter plant. These results suggest that a twin-runner system, controlled by a three-position selector switch depending on scrap grade, could be realized on a production basis. Using the scrap code for the scrap being used the steel mill process computer can determine and set the required switch position when the heat begins...
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Zinkgehalt ? Recycling ? Sinterung ? Klärschlammverwertung ? Reststoffverwertung ? Stahlindustrie ? Staubfilter ? Abfallverwertung ? Altmetall ? Zink ? Staub ? Entstaubung ? Filterstaub ? Hardware ? Industrieabfall ? Linz-Donawitz-Verfahren ? Recyclingquote ? Schlamm ? Energie ? Monitoring ? Stahlerzeugung ? Stichprobe ? Stahl ? Thermisches Verfahren ? Staubgehalt ? Stofftrennung ? Wettbewerbsfähigkeit ?
Region: Nordrhein-Westfalen
Bounding boxes: 6.76339° .. 6.76339° x 51.21895° .. 51.21895°
License: cc-by-nc-nd/4.0
Language: Englisch/English
Time ranges: 1992-12-01 - 1995-05-31
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