摘要
煤气化渣是煤气化工艺产生的固体废弃物,随着煤气化工艺的广泛推广与应用,大量煤气化渣的产生对生态环境造成威胁的同时也制约着煤化工行业的发展。为实现煤气化渣的资源化、工业化利用,以煤气化粗渣为研究对象,对其矿物赋存形态和化学组成进行分析,提出煤气化渣净化除杂-酸浸提铝制备聚合氯化铝(polyaluminum chloride,PAC)的总体构思。利用煤气化渣中各元素与酸溶液的反应活性差异,在低酸体系下浸出Fe^(2+),Ca^(2+)及少部分Al^(3+),再利用离子沉淀pH差异,将钙、铁与煤气化渣选择性分离,实现酸渣富铝。以富铝酸渣为原料,酸浸制备PAC前驱体。考察铝酸钙粉添加量、聚合温度、聚合时间对产品品质及絮凝效果的影响。结果表明:在60%理论耗酸量下,煤气化渣浸出Al^(3+),Fe^(2+),Ca^(2+),将反应液pH调至3.5,Al^(3+)选择性沉淀,固液分离后制备富铝渣,钙、铁的去除率可达84.06%和79.79%,Al_(2)O_(3)质量分数由原来的10.84%提升至14.38%;富铝酸渣添加酸后再次溶出,酸溶液中氧化铝质量浓度可达到28.4 g/L;按固液比为10 g∶100 mL向酸溶液添加铝酸钙粉,在80℃下聚合2.5 h,可获得符合GB/T 22627-2022要求的PAC产品;通过FTIR和XRD对PAC产品进行表征,表明生成的产品为PAC,将该产品应用于模拟废水中,去浊率高达92.90%。
Coal gasification slag is a solid waste produced from coal gasification process.With the extensive promotion and application of coal gasification process,the substantial coal gasification slag production threatens the ecological environment and hampers the development of the coal chemical industry.To facilitate the resourceful and industrialized utilization of coal gasification slag,taking coal gasification slag as the research object,its mineral occurrence form and chemical composition were analyzed,and a comprehensive approach to prepare poly aluminum chloride(PAC) from alumina-rich acidic leach solution was proposed.Firstly,using the difference of reactivity between each element in coal gasification slag and acid solution,Fe^(2+),Ca^(2+) and a small portion of Al^(3+) were leached out under low acid system.Subsequently,the selective separation of calcium and iron salts from the slag was achieved based on ion precipitation pH,enriching the aluminum content in the acid-treated slag.Then,utilizing aluminum-rich acidic slag as the raw material,the acid leaching was used to prepare the precursor of PAC.Moreover,the effects of the amount of calcium aluminate powder added,the polymerization temperature,the polymerization time on the performance of the product and flocculation effect were examined.The results show that in 60% of the theoretical acid consumption,Al^(3+),Fe^(2+),Ca^(2+) are leached from the slag.By adjusting the pH of the reaction solution to 3.5 and facilitating selective precipitation of Al^(3+),the removal ratio of calcium and iron reaches 84.06% and 79.79%,respectively,with Al_(2)O_(3) mass fraction increasing from 10.84% up to 14.38%;Further dissolving the aluminum-rich acidic slag with the theoretical acid amount resultes in an alumina mass concentration of 28.4 g/L;Adding calcium aluminate powder to acid solution at a ratio of 10 g∶100 mL and polymerizing at 80 ℃ for 2.5 h produces PAC that meets the quality of GB/T 22627-2022.FTIR and XRD analysis on the PAC product confirm that the synthesized product is polymerized alumina chloride.The product is applied to simulated wastewater,and the turbidity removal ratio is as high as 92.90%.
作者
李艳欢
伍琴
夏举佩
孙建平
侯翠利
LI Yanhuan;WU Qin;XIA Jupei;SUN Jianping;HOU Cuili(Faculty of Chemical Engineering,Kunming University of Science and Technology,650500 Kunming,China;Shaanxi Coal Chemical Technology Research Institute Company Limited,710100 Xi’an,China;State Key Laboratory of Energy Coal Quality Clean Transformation,710100 Xi’an,China)
出处
《煤炭转化》
CAS
CSCD
北大核心
2024年第4期55-67,共13页
Coal Conversion
基金
陕西煤业化工技术研究院委托技术开发项目(HZ2023K0040A)。
关键词
煤气化粗渣
分步酸浸
选择性沉淀
除杂
聚合氯化铝
coal gasification slag
step acid leaching
selective precipitation
impurity re-moval
polyaluminum chloride
