# Pyrometallurgical Technology for Extracting Iron and Zinc from Electric Arc Furnace Dust
## 4 Experimental EAFD Processing  
The pelletized charge was used for melting in laboratory experiments. The mill scale was de-oiled in a muffle furnace in a nitrogen environment without access to oxygen, thereby avoiding the ignition of the organic fraction. The test charge components were carefully homogenized in a porcelain mortar; water was then added to the resulting homogeneous mix to form a paste-like mass, and spherical granules 10-25 mm in diameter were manually formed. Carboxyl methylcellulose was used as a binder. Wet granules were dried for 30 min at 200 \({}^{\circ}\)C in an EKPS 10 laboratory muffle electric furnace (SKTB, Smolensk, Russia). The pelletized charge underwent reduction melting on a laboratory unit based on a high-temperature LHT 08/17 furnace (Nabertherm, Lilienthal, Germany) equipped with a water-cooled gas flue with the forced removal of gaseous products; see Figure 5.  
The sublimation products formed in the reduction melting were captured using a dust collecting system. Gaseous melting products were discharged through a pipe from the upper part of the furnace's working chamber by induced draft. The sublimed products entered the water-cooled gas flue, where the gas stream cooling, condensation, and partial precipitation of sublimates took place. Dust residues were captured by passing the dust-gas flow through a water filter (a flask with water). \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{A\({}^{4}\), \% *} & \multicolumn{8}{c}{Components} \\ \cline{2-13}  & C & H & O & N & S & SiO\({}_{2}\) & Al\({}_{2}\)O\({}_{3}\) & Fe\({}_{2}\)O\({}_{3}\) & CaO & MgO & K\({}_{2}\)O & Na\({}_{2}\)O & TiO\({}_{2}\) \\ \cline{2-13}  & \multicolumn{8}{c}{Content, wt\%} & \multicolumn{8}{c}{Content in ash, wt\%} \\ \hline
10.51 & 63.99 & 4.38 & 20.05 & 0.80 & 0.27 & 53.5 & 12.3 & 7.2 & 21.4 & 4.1 & 0.5 & 0.4 & 0.6 \\ \hline \hline \end{tabular}  
* A\({}^{4}\)—ash content.  
\end{table} 
Table 4: The chemical composition of DOM coal. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{Material} & \multicolumn{8}{c}{Components} \\ \cline{2-13}  & SiO\({}_{2}\) & CaO & Al\({}_{2}\)O\({}_{3}\) & Fe\({}_{2}\)O\({}_{3}\) & MgO & SO\({}_{3}\) & MnO & TiO\({}_{2}\) & H\({}_{2}\)O \\ \cline{2-13}  & \multicolumn{8}{c}{Content, wt\%} \\ \hline Quartz sand & 97.60 & 0.36 & 0.10 & 0.12 & 0.15 & - & 0.07 & 0.05 & 1.55 \\ \hline Lime & 0.4 & 90.80 & 1.42 & 1.50 & 5.68 & 0.20 & - & - & - \\ \hline \hline \end{tabular}  
\end{table} 
Table 5: The chemical composition of fluxes. To reproduce the reduction conditions in an industrial rotary hearth furnace, the experiments were performed in the following sequence:  
* 20-30 g of hard coal with a particle size of 3.0-4.0 mm was placed in a \(\sim\)55 mL corundum crucible;
* The prepared pelletized charge was placed on the bedding in the crucible;
* A water-cooled refrigeration chamber with the forced removal of gaseous reaction products was mounted at the furnace's off-gas outlet;
* The crucible with bedding and the pelletized charge was placed in a furnace heated to 1150 \({}^{\circ}\)C;
* The charge was reduction melted for 30 min according to the temperature regime defined in the theoretical study;
* The crucible with melting products was removed from the furnace and cooled to room temperature; the melting products were then externally examined and weighed;
* The sublime trap was cleaned, and the trapped and condensed products were weighed. Based on the data obtained on the separation nature, mass, and chemical composition of the charge melting products (granulated pig iron and slag), it was concluded that the charge composition and the chosen melting temperature regime are expedient. In the laboratory furnace, the charge underwent reduction melting in a way, reproducing a similar process in a rotary hearth furnace.