Ash-Melting Process Utilizing Thermite Reaction between Chromium Electroplating Sludge and Aluminum Dross

Abstract

The aim of this work is to evaluate the possible application of the thermite reaction to the melting process of the municipal solid waste incineration ash (MSWI ash). The thermite agent was produced by mixing calcined chromium electroplating sludge with aluminum dross in appropriate stoichiometric proportions and then forming the mix into variously sized balls. The effect of size of the ball on the amount of melted MSWI ash, aggregation of metallic substances in the slag, and the level of environmental safety of generated slag were investigated. The reaction was initiated by heating a mix of single thermite ball and MSWI ash in a muffle furnace, and generated molten slag. The amount of MSWI ash increased with the weight of the thermite balls linearly, and its ratio was from 2.0 to 2.4. Comparative elution tests of untreated MSWI ash, MSWI slag, and thermite-derived slag show the environmental benefits of this type of approach. This paper presents the feasibility of ash melting process with thermite agent, the maximum amount of MSWI ash melted by one thermite ball, and the environmental benefits. Mixing a thermite agent with MSWI ash as an exothermic agent enhances the efficiency of the melting process, alleviates the energy consumption, and can be used to conventional melting techniques.