Characteristics and thermal detinning of ferrous scrap from Spanish MSW compost plants

Abstract

Twenty samples of ferrous scrap from different Spanish municipal solid waste (MSW) compost plants were characterised in order to know their composition and tin contents, with a view to evaluating their metallurgical quality as a raw material for the steel industry. Eighty five percent of the samples had a high metallic fraction weight percentage, constituted principally by food and beverage cans and domestic aerosols. The average tin content was 0.43 wt.%. The ferrous scrap samples were subjected to fragmentation, cleaning and thermal detinning processes in order to improve their quality. The products obtained were chemically, mineralogically, metallographically and spectroscopically characterised. The thermal detinning process, performed at a relatively high temperature (700 °C) and with a short sample holding time in the furnace (10 min), yielded a very high quality ferrous scrap with a very low tin content (<0.05 wt.%) and a low oxidation degree of the steel. The corrosion degree in these conditions was practically negligible.