粉煤灰浸取液与盐湖富镁卤水制备镁铝水滑石及其性质研究

Study on Preparation and Properties of Magnesian Aluminum Hydrotalcite from Fly Ash Leaching Solution and Magnesian-rich Brine of Salt Lake

近些年来,粉煤灰和盐湖老卤镁资源的综合利用逐渐成为人们关注的焦点之一,绿色制备低成本类水滑石是有效的解决方式之一。本文以Na 2 CO_(3)和NaOH为沉淀剂和pH调节剂,以高浓度粉煤灰浸取液中Al 3+和近饱和富镁卤水中的Mg^(2+)为金属离子源,采用共沉淀-水热法,成功制备了镁铝水滑石。通过XRD和SEM的测试分析探讨了陈化温度、陈化时间、镁铝摩尔比、碱液浓度等因素对镁铝水滑石形貌结构的影响。结果表明用加料方式A:将铝源与镁源依次加入碱液中;陈化时间6h;陈化温度140℃;Mg/Al摩尔比2;摩尔比为1;粉煤灰浸取液滴加速度为0.3 mL/min(料液体积为9mL);富镁卤水滴加速度为0.6 mL/min;反应温度60℃;NaOH浓度4 mol/L时,合成的镁铝水滑石为六边形片层结构,形貌更为规整(颗粒粒径为100~200 nm),结晶度更高。本文研究为粉煤灰浸取液和盐湖老卤废弃物的高值化利用奠定一定的理论基础。

In recent years,the comprehensive utilization of fly ash and salt lake old brine magnesium resources has gradually become one of the focuses of people's attention,and the green preparation of hydrotalcite is one of the effective solutions.In this paper,Na 2 CO_(3) and NaOH are used as precipitants and pH regulators,Al 3+in the high-concentration fly ash leaching solution and Mg^(2+)in the nearly saturated magnesium-rich brine are used as the metal ion source,and the co-precipitation-hydrothermal method is used to successfully prepare magnesium Aluminum hydrotalcite.Testing and analysising by XRD and SEM,the influence of factors such as ageing temperature,ageing time,molar ratio of magnesium to aluminum,concentration of lye and other factors on the morphology and structure of magnesium aluminum hydrotalcite was discussed.The results show that using feeding method A:add aluminum source and magnesium source to the lye in turn;aging time 6h;aging temperature 140℃;Mg/Al molar ratio is 2;CO_(2)-3/Al 3+molar ratio is 1;fly ash leaching droplets The acceleration is 0.3 mL/min(the volume of the material liquid is 9mL);the acceleration of the magnesium-rich halogen water droplets is 0.6 mL/min;the reaction temperature is 60℃;when the NaOH concentration is 4 mol/L,the synthesized magnesium-aluminum hydrotalcite has a hexagonal lamellar structure,The morphology is more regular(particle size is 100~200 nm),and the crystallinity is higher.This study lays a certain theoretical foundation for the high-value utilization of fly ash leaching liquid and salt lake brine waste.