| 초록 |
In the steelmaking industry, ferrochromium alloy is a very important raw material now-a-days. Most of the ferrochromium alloys are being produced using the electric furnace in the smelting process. Eventually, this process composed of pre-reduction step and main reduction process. In contrast, silicon sludge is the waste which is being discharged from the silicon ingot cutting process, consists of cutting oil, cooling water, Si, SiC and iron particles overwhelmingly. A large amount of sludge is being produced during the silicon wafer cutting process recently. In this study, the silicon sludge was used to reduce the chromium ore and to make ferrochromium alloy. The mixture of chromium ore and silicon sludge were pressed to make pellets. The pellets were subjected to the reduction at 1300~1500 ºC with the flow of high purity argon. From the exhaust gas analysis, it is found that starting temperature is changed for the samples with different carbon powder addition. In order to get information on the product, the reduction was made for different reaction time. The metal and slag samples were recovered, and their phases and chemical composition were analyzed precisely with various experimental tools such as XRF (X-ray Fluorescence), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS). The reduction ratio was examined with respect to reduction time. The cordierite phase was found mainly in the slag samples. Also, it is found that the metal droplets are coalesced easily for higher reduction temperature. It is estimated this the influence of the viscosities in metal and slag. Present study may provide the very important information on the reduction of chromium ore by the silicon sludge, resulting in the ferrochrome alloy. |
