Efficiency of chlorides removal from zinc-containing products depending on the parameters of calcination by microwave electromagnetic field

The world production and zinc consumption is gradually increasing its recycling. Ferrous and copper-containing dust from the processing of galvanized and brass scrap is one of the main sources of secondary zinc. The use of Waelz technology makes it possible to involve these sources in the production of zinc metal. Waelz oxide is a product of Waelz process of zinc-containing mixture. It is necessary to perform a preliminary removal of chlorides for Waelz oxides usage in zinc production technology. Heating and calcination of zinc-containing products by a microwave field of super-high frequency is a promising method for use in metallurgy. The influence of technological parameters of calcination in electromagnetic field of super-high frequency on the efficiency of chloride-ion removal from zinc-containing product has been investigated in the laboratory conditions. The investigation was performed using the method of mathematical planning of experiments. The laboratory microwave oven with aspiration for capturing fumes and special thermal insulation was used for this investigation. The possibility of zinc-containing products calcination when influencing of microwave field of super-high frequency has been confirmed. During investigation the dependences of the initial mass of the sample, the radiant power of the microwave field of super-high frequency and the duration of calcination on the efficiency of chloride-ion removal from the zinc-containing product have been identified. For visualization, the results of the performed investigations are given in the form of graphs and tables of the dependence of changes in the power and duration of calcination, and the initial mass on the efficiency of chloride-ion removal from zinc-containing product. The possibility of chlorides removal from zinc-containing product to their residual content of 0.05 wt.% is shown under the following conditions: microwave oven power - 1400 W, calcination process duration - 600 seconds and initial sample weight - 20 grams.