Accelerating the Decrease of Free CaO in Basic Oxygen Furnace

• Main Authors: I-Shiun Lin, 林益璇
• Other Authors: Chien-Kuei Chang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/70590323450760672513

碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系 === 99 === “Basic Oxygen Furnace Slag” is the industrial wastes in an “Integrated Steel Mill”. The physical-chemical properties of Basic Oxygen Furnace Slag are between blast furnace slag and electric furnace slag. However, their application is much lower than blast furnace slag. In past decades, “sea dumping” was the most adopted way for treatment of Basic Oxygen Furnace Slag. Until 1972, the resourced study of Basic Oxygen Furnace Slag was conducted by many countries due to the “Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter”(London Convention) and the “1996 London Protocol” passed by United Nations. In this work, the chemical immersion was investigated. The control factors include the particle size of Basic Oxygen Furnace Slag, sampling time, vacuum degree, solvent concentration, pH, and reaction time. Different solvents including the sulfuric acid, nitric acid, hydrochloric acid, sodium carbonate and water were also investigated for comparing the treating feasibility of f-CaO. The results demonstrated that the microstructure of Basic Oxygen Furnace Slag have both porosity and non-porosity characteristics. The cross section pictures (SEM/EDS) showed the f-CaO was covered by iron oxide and manganese oxide. Therefore, inside f-CaO cannot be decomposition directly. But it cannot be confirmed the f-CaO could be decreased below 1.2 % after long time immersion, indicating that it is difficult to convert Basic Oxygen Furnace Slag to aggregate directly. Keywords: Basic Oxygen Furnace Slag, f-CaO, vacuum treatment, chemical immersion, porosity