| 摘要 |
<p>PURPOSE: To produce fine artificial aggregate for concrete which is made non- polluting and is densely crystallized from molten slag of incineration ashes, dried powder of sewer sludge, etc. CONSTITUTION: The incineration ashes, etc., 4 compounded with coke breeze are reduction melted by a submerged arc fusing method by using an electric melting furnace to reduce the easily reducible metal oxides of Fe, Cr, P, etc., in the incineration ashes, etc., 4 to form molten pig iron 5. Simultaneously, molten slag 6 consisting essentially of SiO2 , etc., having a low gas content is formed on the molten pig iron 5. This molten slag 6 is rapidly extracted and is immediately splashed toward a water cooled wall in order to suppress the heat radiation at the time of slagging off, etc., of the molten slag 6 so that the molten slag 6 is formed to finer grains by collision against the water cooled walls. After sand grain-like slag 8 having solidified surfaces is formed, the slag is accumulated in a furnace body 3A before its temp. falls. The slag is then held in a temp. atmosphere of 800 to 900 deg.C for 3 to 4 hours. The sand grain-like slag 8 having the shells formed amorphous crystallizes overall to form the aggregate approximate to natural sand.</p> |
