赤泥-钢渣基免烧陶粒的制备及除磷特性研究

Study on Preparation and Phosphorus Removal Characteristics of Red Mud and Steel Slag Based Non-Sintered Ceramsite

针对传统烧结陶粒制备过程中成本高、能耗大的缺点,以赤泥和钢渣为主要原料,通过免烧工艺制备出了具有磷吸附性能的陶粒。以解体率为其力学性能指标,通过正交实验确定了陶粒的最佳质量配比(赤泥、钢渣质量比4:3、稻壳灰添加量10%、石膏添加量4%、水泥添加量10%),最佳制备工况下的陶粒解体率为3.90%;所制作陶粒无重金属浸出风险,属于环境友好型材料。陶粒对水中磷的吸附特性实验结果表明,陶粒在酸性溶液中具有最佳的除磷效果;对于初始磷浓度为20 mg/L的溶液,设置30 g/L的陶粒投加量,除磷率可达96.40%;陶粒吸附过程遵循准二级动力学模型和Langmuir等温吸附模型,最大理论吸附量为0.99 mg/g;磷与陶粒表面的CO_(3)^(2-)、Ca^(2+)、Fe^(3+)、Al^(3+)发生离子交换和磷酸盐共沉淀反应,是水中的磷去除的机理,沉淀物质主要由Ca_(3)(PO_(4))_(2)、FePO_(4)、AlPO_(4)组成。

This study addresses the high cost and energy consumption associated with traditional sintered ceramsite production by preparing ceramsite with phosphorus adsorption properties using a non-sintered process.Red mud and steel slag were utilized as the primary raw materials.Through orthogonal experiments,the optimal mass ratio for ceramsite production was determined to be a red mud to steel slag ratio of 4:3,with 10%rice husk ash,4%gypsum,and 10%cement.Under these optimal conditions,the disintegration rate of the ceramsite was 3.90%.The resulting ceramsite poses no risk of heavy metal leaching and is classified as an environmentally friendly material.Adsorption experiments demonstrated that the ceramsite effectively removes phosphorus from water,with the highest removal efficiency observed in acidic solutions.At an initial phosphorus concentration of 20 mg/L and a ceramsite dosage of 30 g/L,the phosphorus removal rate reached 96.40%.The adsorption process adhered to both the quasi-two-stage kinetic model and the Langmuir adsorption isotherm model,with a maximum theoretical adsorption capacity of 0.99 mg/g.The mechanism of phosphorus removal involves ion exchange and phosphate co-precipitation with CO_(3)^(2-),Ca^(2+),Fe^(3+),and Al^(3+),resulting in the formation of precipitates primarily composed of Ca_(3)(PO_(4))_(2),FePO_(4),and AlPO_(4).