铁尾矿人工湿地填料的制备及其成孔机理研究

Study on the Preparation of Filler Using Iron Tailings for Constructed Wetlands System and Its Mechanism of Pore Formation

为解决铁尾矿堆积问题,以铁尾矿和木屑粉为主要原料,制备出性能较好的铁尾矿人工湿地填料FITCWS。该填料焙烧前后的主要矿物成分由长石和角闪石转变为辉石。焙烧温度(T)、木屑粉用量(η)、木屑粉粒径(dw)和尾矿粒径(di)均可影响FITCWS的物理性能。T是影响吸水率和颗粒强度的主要因素,dw和di是影响比表面积和孔容的主要因素,dw、T和di是影响孔径的主要因素。T越高,FITCWS的颗粒强度越大,吸水率越低;dw和di越小,FITCWS表面的粗糙度越低,比表面积、孔容和孔径越大。制备FITCWS的优选方案是:η为0.3,T为1200℃,dw和di均为200~250目(58~74μm),所制FITCWS的吸水率为44%,颗粒强度为115.9 N,比表面积为6.932 m^(2)/g,孔容为0.017 cm^(3)/g,孔径为3.169 nm,孔形为通透的狭缝。

In order to solve the problem of iron tailings accumulation,the filler with good properties for constructed wetlands FITCWS was prepared using iron tailings and wood dust as the main raw materials.During calcination,the main mineral composition of the FITCWS were changed from feldspar and hornblende to augite.Temperature(T),the amount of wood powder(η),the particle size of wood powder(dw)and tailings(di)had impacts on the physical properties of FITCWS.The main influencing factors of water absorption and particle strength were T,the main influencing factors of specific surface area and pore volume were dw and di,and the main influencing factors of pore width were dw,T and di.With the increase of T,the particle strength of FITCWS was increased also,however the water absorption was opposite.The specific surface area,pore volume and pore width were increased with the decrease of dw and di,whereas the surface of FITCWS particles became smooth.The optimal experimental scheme for the preparation of FITCWS was as follows:ηwas 0.3,T was 1200℃,dw and di were both 200-250 of mesh(58-74μm).The water absorption rate,particle strength,specific surface area,pore volume and pore width of prepared FITCWS were 44%,115.9 N,6.932 m^(2)/g,0.017 cm^(3)/g and 3.169 nm,respectively,and the pores were narrow and permeable.