【作者】 吴金龙；

【导师】 程乐鸣； 施正伦；

【作者基本信息】 浙江大学 ， 工程热物理， 2021， 硕士

【摘要】 近年来,随着国内CFB（Circulating Fluidized Bed）燃煤锅炉数量和容量的增加,脱硫灰渣的产量大规模增长,其资源化、高值化和高性能化利用已是当前大宗固废发展的趋势。在当前节能减排的大背景下,水泥行业由于其高能耗、高CO₂排放的特性受到社会和政策的重点关注。水泥种类中,硫铝酸盐水泥在减少碳排放方面比硅酸盐水泥更具有优势,且因其具有早期强度发展快、耐腐蚀性能优异等特点,已成为我国产量最大的非硅酸盐类特种水泥。本文依托国家重点研发计划课题,针对贵州威赫660MW国家示范项目产生的CFB高钙脱硫灰渣开展其在硫铝酸盐水泥方面的应用探究。一方面,试验分别以CFB高钙脱硫灰和脱硫渣为原材料烧制硫铝酸盐水泥熟料,主要研究煅烧温度和配料参数对熟料抗压强度、f-CaO（free-calcium oxide）含量和矿物组成的影响,并对熟料水化放热特性给予表征。另一方面,试验将CFB脱硫灰渣作为掺合料以不同比例直接掺入硫铝酸盐水泥中,探究掺合料种类、掺加量对水泥抗压强度、凝结时间和膨胀率的影响。本文主要工作和结论如下:（1）试验研究了煅烧温度和碱度系数对熟料强度、f-CaO含量的影响。在熟料烧成区间1250℃-1350℃内,熟料抗压强度随煅烧温度升高而增大,随养护龄期延长而增大,熟料中f-CaO含量随温度升高而降低,随碱度系数Cm值增大而增大。使用脱硫灰制备熟料的最佳碱度系数Cm=1,使用脱硫渣制备熟料的最佳碱度系数Cm=0.98。相同条件下,渣体系熟料中f-CaO含量高于灰体系,抗压强度小于灰体系;（2）试验研究了熟料的矿物组成和影响因素,并对熟料水化过程进行表征。试验制备的熟料含有的主要矿物和设计值相近。熟料烧成温度区间内,温度升高对主要矿物的形成具有促进作用。相较于无水硫铝酸钙,熟料在水化时过程更复杂,水化时间更长;（3）试验将脱硫灰渣作为掺合料,以5%-25%不同比例直接掺入硫铝酸盐水泥中,得到结论:5%-25%掺量范围内,复掺体系抗压强度与脱硫灰渣掺入量关系为负相关,膨胀率与灰渣掺量正相关。脱硫灰渣掺入量≥10%时,脱硫灰渣具有缓凝作用,凝结时间满足标准。灰渣掺入量≤10%时,脱硫灰渣具有限制膨胀率的作用,膨胀率小于原水泥。更多还原

【Abstract】 In recent years,with the increase of the number and capacity of CFB boilers,the output of desulfurization ash has increased on a large scale,and its utilization of resources,high value and high performance has become the development trend of bulk solid waste.In the current context of energy conservation and emission reduction,cement industry has attracted the focus of social and policy attention due to its high energy consumption and high CO₂ emission.Sulphoaluminate cement has more advantages in reducing carbon emissions than Portland cement,and because of its high early strength,excellent corrosion resistance and other characteristics,it has become the largest non-silicate special cement in China.In this paper,the application of CFB high-calcium desulfurization ash and slag produced in Guizhou 660MW National Demonstration Project is investigated based on the national key research and development program.On the one hand,CFB high-calcium desulfurization ash and slag were used as raw materials to produce sulphoaluminate cement clinker.The effects of calcination system and ingredients parameters on the compressive strength,f-CaO content and mineral composition of the clinker were mainly studied,and the hydration characteristics of the clinker were characterized.On the other hand,CFB desulfurization ash and slag were used as admixtures to directly add sulphoaluminate cement in different proportions,so as to explore the influence of the type and amount of admixtures on the compressive strength,setting time and expansion rate of cement.The main research work and conclusions of this paper are as follows:（1）Effects of calcination temperature and alkalinity coefficient on clinker strength and f-CaO content:In the clinker firing range between 1250℃and 1350℃,the compressive strength of clinker increases with the increase of calcination temperature and the prolongation of curing age,the content of f-CaO in the clinker decreases with the increase of temperature and increases with the increase of alkalinity coefficient Cm value.The optimal basicity coefficient of the clinker prepared with desulfurization ash is Cm=1,and that prepared with desulfurization slag is Cm=0.98.Under the same conditions,the content of f-CaO in the slag system is higher than that in the ash system,and the compressive strength is lower than that in the ash system.（2）The mineral composition and influencing factors of clinker were studied,and the hydration process of clinker was characterized.The main minerals in the prepared clinker are close to the design values.In the range of clinker firing temperature,the increase of temperature can promote the formation of main minerals.Compared with anhydrous calcium sulfoaluminate,the hydration process of clinker is more complex and the hydration time is longer.（3）In the experiment,desulfurization ash slag was used as admixture and directly mixed into sulphoaluminate clinker at different proportions of 5%-25%,and the conclusions are drawn as follows:within the content range of 5%-25%desulfurization ash and slag,the relationship between the compressive strength of the complex doping system and the content of desulfurization ash is negatively correlated,and the expansion rate is positively correlated with the content of ash,the compressive strength of the mixing system is negatively correlated with the amount of admixture,and the expansion rate is positively correlated with the amount of admixture.When the content of the admixture is more than 10%,the desulfurization ash and slag have the retarding effect,and the setting time meets the requirements of the standard.When the amount of admixture is less than 10%,the desulfurization ash and slag have the function of limiting the expansion rate,and the expansion rate is less than the original cement.更多还原