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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Optimisation of electric arc furnace dust recycling and zinc recovery by scrap de-zincing

Janjua, Rizwan Ahmed 24 July 2009 (has links) (PDF)
A considerable rise in the Electric Arc Furnace steelmaking has taken place in the EU during the last decade. As a result, the amount of steelmaking dust has increased as well. This dust is recycled in order to recover the valuable amount of zinc present in it. In contrast to the increase in dust generation, the capacity of recycling sites has not changed accordingly and there are growing concerns over this imbalance. In the present thesis, logistics and resource allocation of dust recycling in the EU are analysed. Data collected through a questionnaire survey was used to formulate the transportation model of linear programming. The results of the model highlight the location of gaps in recycling capacity and its uneven geographical distribution. The state of the recycling can be improved by research in scrap de-zincing; a process that can recover most of the zinc prior to steelmaking thereby lowering the total amount of dust. To this effect experiments were conducted using electro-galvanized scrap samples in order to study the kinetics of zinc evaporation. Various parameters such as the flow rate of carrier gas, scrap heating rate, packed bed voidage, permeability, and specific surface area were studied with a view of a possible scale-up of the process. The results show that there is a potential of integrating the de-zincing step into high temperature scrap pre-heating processes using shaft type systems that utilize off-gases of steelmaking and auxiliary burners.
2

Optimisation of electric arc furnace dust recycling and zinc recovery by scrap de-zincing

Janjua, Rizwan Ahmed 09 September 2008 (has links)
A considerable rise in the Electric Arc Furnace steelmaking has taken place in the EU during the last decade. As a result, the amount of steelmaking dust has increased as well. This dust is recycled in order to recover the valuable amount of zinc present in it. In contrast to the increase in dust generation, the capacity of recycling sites has not changed accordingly and there are growing concerns over this imbalance. In the present thesis, logistics and resource allocation of dust recycling in the EU are analysed. Data collected through a questionnaire survey was used to formulate the transportation model of linear programming. The results of the model highlight the location of gaps in recycling capacity and its uneven geographical distribution. The state of the recycling can be improved by research in scrap de-zincing; a process that can recover most of the zinc prior to steelmaking thereby lowering the total amount of dust. To this effect experiments were conducted using electro-galvanized scrap samples in order to study the kinetics of zinc evaporation. Various parameters such as the flow rate of carrier gas, scrap heating rate, packed bed voidage, permeability, and specific surface area were studied with a view of a possible scale-up of the process. The results show that there is a potential of integrating the de-zincing step into high temperature scrap pre-heating processes using shaft type systems that utilize off-gases of steelmaking and auxiliary burners.

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