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Laboratory production of calcium sulfoaluminate cements with high industrial waste content
Cement & Concrete Composites ( IF 10.5 ) Pub Date : 2019-11-22 , DOI: 10.1016/j.cemconcomp.2019.103475
Oğulcan Canbek , Sahra Shakouri , Sinan T. Erdoğan

A drawback of conventional calcium sulfoaluminate (CS̄A) cement production is the use of the costly raw material bauxite as a source of alumina to form the main clinker phase ye'elimite. Replacement of bauxite with industrial wastes can benefit CS̄A cements economically and environmentally. This study demonstrates the use of high amounts of red mud, a sulfate-rich/high-lime fly ash, and desulfogypsum as raw materials in producing CS̄A clinkers and cements with better mechanical performances than an all-natural raw material CS̄A reference cement. Mineralogical compositions of the clinkers and hydrated cement pastes were investigated using x-ray diffraction, isothermal calorimetry, thermogravimetric analysis and scanning electron microscopy. Compressive strength development of mortars, made with citric acid, were studied up to 28 d. It was found that increasing fly ash increases the belitic nature, and increasing red mud increases the ferritic nature of the clinkers. Mortars with 28-d strengths exceeding 40 MPa could be made with cements containing ~38% waste and only half the bauxite in the reference. Medium early and ultimate strength mortars could be made with a ~55% waste cement when bauxite was reduced to a quarter of the reference, with small additions of Ca(NO3)2·4H2O or Li2CO3. Desulfogypsum, as a source of sulfates, was more beneficial to strength development than natural gypsum. Ye'elimite reactivity was enhanced in red-mud containing cements. Cements with both fly ash and red mud experienced lower carbonation than those made with only one of the two wastes.



中文翻译:

具有高工业废料含量的硫磺铝酸钙水泥的实验室生产

常规的硫铝铝酸钙(CS̄A)水泥生产的一个缺点是使用昂贵的铝土矿原料作为氧化铝的来源,以形成主要的熟料相。用工业废料代替铝土矿可以使CS̄A水泥在经济和环境方面受益。这项研究表明,在生产CS̄A熟料和水泥中,使用大量的赤泥,富含硫酸盐/高石灰的粉煤灰和脱硫石膏作为原材料,比全天然的CS̄A参比水泥具有更好的机械性能。使用X射线衍射,等温量热法,热重分析和扫描电子显微镜研究了熟料和水合水泥浆的矿物学组成。研究了用柠檬酸制得的砂浆的抗压强度,直到28天。发现增加的粉煤灰增加了贝氏体性质,增加的红泥增加了熟料的铁素体性质。28d强度超过40 MPa的砂浆可以用水泥制成,水泥中含〜38%的废料,而铝土矿的参考量仅为一半。当铝土矿减少到参考值的四分之一时,用少量的Ca(NO)可以用〜55%的废水泥制成中度早期和极限强度的砂浆。32 ·4H 2 O或Li 2 CO 3。作为天然硫酸盐的来源,脱硫石膏比天然石膏更有利于强度发展。在含有赤泥的水泥中,极限活性提高。既有粉煤灰又有赤泥的水泥比仅由两种废物之一制成的水泥的碳化程度较低。

更新日期:2019-12-11
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