高钙粉煤灰固碳降碱反应特性及煤矿井下规模化利用新途径  

Reaction characteristics of carbon fixation and alkali reduction in high calcium fly ash and new way of large-scale utilization in coal mine

作　　者：尹希文 于秋鸽[1,2] 甘志超 浮耀坤 樊振丽[1,2] 纪龙 YIN Xiwen;YU Qiuge;GAN Zhichao;FU Yaokun;FAN Zhenli;JI Long(CCTEG Coal Mining Research Institute,Beijing 100013,China;Coal Mining and Design Branch,China Coal Research Institute,Beijing 100013,China;College of Engineering,Huazhong Agricultural University,Wuhan 430070,China)

机构地区：[1]中煤科工开采研究院有限公司,北京100013 [2]天地科技股份有限公司开采设计事业部,北京100013 [3]华中农业大学工学院,湖北武汉430070

出　　处：《煤炭学报》2023年第7期2717-2727,共11页Journal of China Coal Society

基　　金：国家重点研发计划资助项目(2022YFB4102100);陕西省厅市联动重点资助项目(2022GD-TSLD-40);天地科技开采设计事业部科技创新基金资助项目(KJ-2021-KCQN-03)。

摘　　要：高钙粉煤灰浆pH较高,直接用于煤矿井下防灭火易污染地下水。为研究CO_(2)矿化利用粉煤灰制井下防灭火材料固碳降碱反应特性,选取陕北某煤电一体化企业粉煤灰为样品,通过XRF、XRD分析了粉煤灰组分及物相结构,利用N2和CO_(2)的混合气模拟电厂烟气,开展了CO_(2)矿化利用粉煤灰实验室小试及扩试试验,研究了粉煤灰固碳降碱反应过程中浆液pH变化规律及模拟烟气CO_(2)体积分数、烟气流量、固液比、温度、搅拌方式等关键参数对矿化反应过程的影响,并从粉煤灰固碳降碱浆液特性、矿化反应装置研制等方面提出了井下规模化应用有待攻克的关键技术,研究结果表明:(1)粉煤灰原样中富含Ca^(2+)、Mg^(2+)、K^(+)、Al^(3+)等碱金属元素,其中CaO质量分数高达17.8%;(2) CO_(2)与粉煤灰中含Ca^(2+)、Mg^(2+)等碱性矿物产生矿化反应,反应后CO_(2)以方解石型碳酸钙附着在粉煤灰球形颗粒表面,表明了高钙粉煤灰固碳降碱具有可行性;(3)矿化反应过程中,浆液pH下降呈“慢—快—慢”3个阶段,当粉煤灰浆液pH降至7.0~7.5后,浆液返碱p H不会超过9,满足煤矿井下粉煤灰防灭火材料要求;(4)确定了最优矿化反应参数为CO_(2)体积分数10%~15%、固液比300 g/L、每升浆液的烟气流量1.0 L/min、温度不高于55℃;(5)综合考虑固碳量、降碱返碱速度以及反应规模等因素,提出了涡流式反应器与旋桨式反应器串并联两级耦合反应系统。High calcium fly ash slurry has a high pH value,which is prone to contaminating groundwater when it is directly used for fire prevention and extinguishing in gob.To study the reaction characteristics of carbon fixation and alkali reduction in the production of underground fire extinguishing materials using fly ash by CO_(2) mineralization,the fly ash from a coal and electricity integrated enterprise in northern Shaanxi is used to analyze its composition and phase structure through XRF and XRD.At the same time,using a mixture of N2 and CO_(2),laboratory experiments on CO_(2) mineralization is conducted to analyze the variation law of pH value during the carbon fixation and alkali reduction reaction process of fly ash,and the influence of key parameters such as CO_(2) concentration,gas flow rate,solid-liquid ratio,temperature and stirring method on the mineralization reaction process.Also,the key technologies that need to be addressed for a large-scale underground application are proposed from the characteristics of fly ash carbon fixation and alkali reduction,development of mineralization reaction equipment,diffusion law of slurry in gob,and the entire preparation process.The research results indicate that fly ash is rich in alkali metal elements such as Ca^(2+),Mg^(2+),K^(+),Al^(3+),with CaO content of up to 17.8%,belonging to high calcium ash.CO_(2) can be reacted with Ca^(2+),Mg^(2+) in the fly ash and CO_(2) is attached to the surface of spherical particles of fly ash with calcium carbonate type after the reaction,indicating the feasibility of carbon sequestration and alkali reduction of high calcium fly ash.During the mineralization reaction process,the pH value of the slurry decreases in three stages:slow-fast-slow.When the pH value of the fly ash slurry drops to 7.0-7.5,the pH value return will not exceed 9,meeting the requirements for fire prevention and extinguishing materials for coal mine gob.The optimal mineralization reaction parameters are that CO_(2) concentration being of 10%-15%,solid-liquid ratio

关 键 词：高钙粉煤灰 矿化反应 固碳降碱 防灭火材料 两级耦合反应装置 

分 类 号：TD745[矿业工程—矿井通风与安全] TD849