铁尾矿与碱渣基核壳高强陶粒的制备与性能研究

碱渣和细铁尾矿属污染性大宗固体废弃物，为了确定以它们为主要原料制备高强环保陶粒的可能性，进行了核壳结构烧结陶粒的制备工艺条件研究，并对主要工艺条件下烧结陶粒的矿物成分进行了分析。结果表明：①铁尾矿和碱渣用量增大，煅烧温度升高，煅烧时间延长，核壳结构烧结陶粒的吸水率、膨胀率均升高，筒压强度和堆积密度总体均降低，只是在较低煅烧温度、较短煅烧时间情况下核壳结构烧结陶粒的筒压强度均较低。②铁尾矿用量为70%，碱渣用量为6%，煅烧温度为1 140 ℃，煅烧时间为90 min情况下，核壳结构烧结陶粒的吸水率为1.25%、膨胀率为1.24%、堆积密度为870.3 kg/m3、筒压强度为10.67 MPa，符合国家标准中高强陶粒的要求（吸水率＜10%、堆积密度等级＜900 kg/m³、筒压强度等级＞6.50 MPa）。③该陶粒碎磨产品（0.075~0 mm）氯离子渗出率为0.000 1%，远低于标准中I类砂≤0.01%的要求。④核壳结构烧结陶粒核芯配合料中的碱渣是促进蓝晶石形成的重要原料，蓝晶石是影响该陶粒强度的关键性矿物，升高煅烧温度和延长煅烧时间均能促进陶粒中含氯化合物的形成，防止掺加碱渣的陶粒中氯离子的渗出。

Preparation and Performance of High-strength Ceramisite with Core-Shell Structure Based on Iron Tailings and Alkaline Residue

The alkaline residue and fine iron tailings belong to the polluted bulk solid waste， in order to determine the possibility of prepared the high strength and environmental ceramisite using them as main material， the preparation conditions of sintering ceramisite with core-shell structure were investigated， and the mineral composition of sintering ceramisite at the important technological conditions was analyzed. The results indicate that: ① with the dosage increasing of iron tailings and alkaline residue， and calcined temperature increase and calcined time prolonging， the water absorption and expansion rate of sintering ceramisites with core-shell structure increased， as a whole， the cylinder compressive strength of them decreased， which were lower only at the lower calcined temperature and shorter calcined time. ② The sintering ceramisites of core-shell structure with the water absorption of 1.25%， expansion rate of 1.24%， bulk density of 870.3 kg/m3 and cylinder compressive strength of 10.67 MPa were prepared， when the dosage of iron tailings and alkaline residue is 70% and 6%， respectively at the condition of 1 140 ℃ calcined temperature and 90min calcined time， it can meet the requirement of high strength ceramisite in the national standard （for the water absorption＜10%， bulk density grade＜900 kg/m³ and cylinder compressive strength grade＞6.5 MPa）. ③ The chloride exudation rate of the ground product （0.075~0 mm） for this ceramisite was 0.000 1%， which is far lower than that of class I sand （≤0.01%） in the national standard. ④ In the core batch of sintering ceramisite with the core-shell structure， the alkaline residue is the important raw material for promoting the formation of kyanite， which is a key mineral for influencing the cylinder compressive strength of this ceramisite， and the formation of chlorine compound in the ceramisite was promoted through elevating calcined temperature and prolonging the calcined time， and it can prevent the chloride exudation of this ceramisite with the addition of alkaline residue.