摘要: |
以城市垃圾焚烧飞灰(MSWIFA)和焚烧底灰(BA)为原料,成功制备了一种以β型硅酸二钙(β-C2S)为主的低钙固碳水泥熟料.结果表明:熟料在1 150~1 250 ℃之间均可被烧结,且实际所需的n(Ca)/n(Si)值要高于理论设计值,即n(Ca)/n(Si)>2.6,否则容易过烧且易形成钙铝黄长石,不利于水泥强度的发展;n(Ca)/n(Si)值对水泥早期抗压强度和碳化程度的影响较大,总体来说抗压强度随着n(Ca)/n(Si)值的增加呈递减趋势,n(Ca)/n(Si)=2.8~3.2时水泥碳化养护2 d的抗压强度基本维持在50 MPa以上,甚至高达72 MPa;当n(Ca)/n(Si)值升至3.3~3.7时,水泥的抗压强度降至25~30 MPa,CaCO3生成量基本维持在12.00%左右;关于熟料各矿物的水化及碳化作用对其强度的贡献还需要进一步探究. |
关键词: 工业固废 低钙固碳 n(Ca)/n(Si) 矿物形成 煅烧温度 |
DOI:10.3969/j.issn.1007-9629.2022.11.002 |
分类号:TQ172.1 |
基金项目:国家自然科学基金资助项目(52250710158) |
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Composition Design and Sintering Process of Solid Waste-Based Low-Calcium Carbon-Fixing Cement Clinker |
WANG Xiaoli, LING Tungchai
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College of Civil Engineering, Hunan University, Changsha 410082, China
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Abstract: |
A low-calcium carbon-fixing cement clinker mainly composed of β-C2S was successfully manufactured using from municipal solid waste incineration fly ash and bottom ash. The results show that the clinker can be sintered at 1 150-1 250 ℃, and the actual n(Ca)/n(Si) value required is higher than the theoretical design value, that is, n(Ca)/n(Si)>2.6. Otherwise, it is easy to over sinter and prone to produce calcium alumina feldspar, which is not conducive to the clinker strength development. n(Ca)/n(Si) value has a significant influence on the early compressive strength and carbonation degree of cement, and the compressive strength decreases with the increase of n(Ca)/n(Si) value. The produced cement with n(Ca)/n(Si)=2.8-3.2 upon 2 days of carbonation can attain a compressive strength of 50 MPa, or even up to 72 MPa. However, when the n(Ca)/n(Si) value increases to 3.3-3.7, the compressive strength drops to 25-30 MPa with CaCO3 content of about 12.00%. Future research is needed to elucidate the role of hydration and carbonation mechanism of various minerals in contributing the strength development. |
Key words: industrial waste low-calcium carbon-fixing n(Ca)/n(Si) mineral formation sintering temperature |