A study was made on the processing of domestic blast furnace slag by flotation and chemical purification for the use of slag as a raw material in making soda lime glasses. Feasibility study has been made for the use of reprocessing slag as a source material for both coloring and chemical components (such as CaO, $Al_2O_3$, MgO and etc.) in the glass making process. Chemical composition of chemically purified slags ranges; $SiO_2$ 34.5~37.5, $Al_2O_3$, 16.2~14.1, $Fe_2O_3$ 0.33~0.14, CaO 34.5~38.8, MgO 4.0~5.2, NmO 0.16~0.39, <TEX>$TiO_2$</TEx> 0.23~0.35, S 0.08~0.42, ignition loss 3.3~8.4 and others 0.48~0.51%. It was found that either amber or greenish color could be easily obtained with the addition of salg up to 24%, however the slag addition to glass batches much impaired the transmitancy of glass products, thus a glass made with 7% slag addition showed 82% in transmitancy value at 510 nm.