Electric arc furnace dusts are among the most environment polluting wastes. Numerous utilization technologies have been developed for dusts containing up to 4% of Zn and more than 20% of Zn. However, the remaining part of steelmaking dusts are the most problematic ones, as they are mostly dumped generating costs and posing serious environmental threats. This paper provides an analysis of the potential utilization options for dusts containing ca. 10% of zinc generated in a single electric steelmaking shop. Physical and chemical properties of dusts have been determined and examined, and furthermore, results of the studies on the EAFD utilization in production of cement clinker and industrial glass have been discussed. It has been found that a particularly beneficial feature of the production technology proposed is that the iron content exceeds 30%. The influence of the dusts used on the functional properties of the products obtained has been established as well as the environmental impact of the processes and products in question and the dust mass possible to be utilized in the production technology proposed have been determined.
The iron and steel industry is one of the largest sources of waste materials, primarily in the form of steelmaking dusts, sludge and slag. Those wastes are a serious threat to the environment. Main precondition for the protection of natural resources in the environment is to recover raw material and energy from waste. The use of waste as raw materials does not involve the storage and creates the possibility of closure of the existing landfill. The article presented utilization of same metallurgical waste containing 4-20 wt. % zinc in non-metallurgical industry. Performed chemical analyzes of pollutants contained in waste tested (dusts, sludge and slag) and in manufactured products (cement bricks, ceramic construction materials, colored glass products and slag for road construction). Aqueous extracts analysis results were compared with the maximum values for the sewage entering into water and soil. The performed research proves that proposed technologies (production of cement clinker, construction bricks, hollow glass, decorated glass) do not pose threat to environment. Harmful impurities are eluted from the products – clinker, constructions bricks and slag after the recovery of zinc recovery. Proposed technologies substitution of primary raw materials recyclable materials can reduce environmental degradation.
The mill scale is a waste from the iron and steel industry. Due to the high content of iron in the form of oxides, it is an attractive material for the recovery of metallic iron by reduction. The product of mill scale reduction is an iron with a very extended surface and a high affinity for oxygen. The smaller iron particles are, the easier it is for spontaneous rapid oxidation, which can be linked to pyrophoricity. This article presents results of experiments using the TG/DTA thermal analysis method aimed at verifying the possibility of recovering iron from the mill scale by a reduction with carbon monoxide at 850 °C, 950 °C, and 1050 °C, taking into account the phenomenon of secondary oxidation in contact with oxygen from air at temperatures of 300 °C, 350 °C, and 400 °C. Two forms of mill scale were used for tests, in the original state and after grinding to develop the surface.
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