Abstract
Depleting iron-ore deposits put the problem of processing poorer and hard-to-dress ores point-blank. Developing blast-furnace ironmaking as the key iron ore processing technique is hindered by the growing shortage of coking coal and significant environmental issues. The research is aimed at studying the impact of the charge reduction parameters and composition on the direct-reduced (granulated) ironmaking when processing South Ural Bakal Mining Administration LLC’s siderite ore (Bakal, Chelyabinsk Region) to obtain granulated iron. The research object was siderite ore samples with an iron oxide content of ~49.5 % wt. (according to X-ray fluorescence analysis). The basic ore sample minerals are siderite (~90 %) and dolomite (~10 %); traces of quartz are also detected. As a reducing agent to extract iron from ores, the Shubarkol deposit (Karaganda, Kazakhstan) coal with 0.25 mm particles was used. Magnesite and calcium and silicon oxides (with 0.1 mm max. particles) were added to the charge as fluxes to obtain a slag of the following composition, % wt.: 25 CaO, 55 SiO2, 20 MgO. Carboxymethyl cellulose was used as a binder in the charge sintering technology adjustment experiments. The temperature regime of the pelletized charge melting was as follows: furnace charging at 1200°C, gradual (for 10 min) heating up to 1350 °C, heating up to 1400°C for the next 10 min, and holding at this temperature for 5 min. The experiments confirmed the possibility of ironmaking from the siderite ore being studied, however, the iron extraction turned out to be quite low – 38 %. It is further planned to concentrate this ore and perform experiments to obtain granulated iron from the concentrate.
Keywords:
Bakal Mining Administration, siderite ores, granular pig iron, pellets, slag, pig iron.