制浆造纸厂富铁污泥性质及其回用为污泥调理剂研究
Study on Properties of Iron？？Rich Sludge in Pulp and Paper Industry and Its Recycling as Sludge Conditioning Agent

针对制浆造纸废水芬顿氧化过程产生的富铁污泥含铁量高的优势,及其易引起混合污泥脱水困难的问题,提出对富铁污泥进行酸处理溶出其中的Fe3+,以用作污泥调理剂的资源化利用新思路。采用元素分析仪、X射线荧光分析仪(XRF)和电感耦合等离子体发射光谱仪(ICP？？OES)等分析富铁污泥的组成,采用X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)分析富铁污泥中铁元素的存在形式;以铁的溶出率和酸消耗量为指标优化酸处理富铁污泥的反应条件,以污泥比阻的降低程度为指标评价制得的污泥调理剂的调理效果,并与FeCl3进行对比。结果表明:富铁污泥中铁的质量分数可达39？？32％,主要以三价的水合氧化铁形式存在;常温下富铁污泥酸处理的优化条件是硫酸与绝干富铁污泥的质量比为0.91 g/g,反应时间为180 min,在此条件下铁溶出率可达57.24％。经酸处理后的富铁污泥制得的调理剂在投加量(以铁质量计)为城市污水处理厂剩余污泥干质量的3.45％时,可将污泥比阻降为其初始值的17.90％,与FeCl3的污泥调理效果相当,这说明该方法是制浆造纸厂富铁污泥资源化利用的一种可行工艺。
Iron？？rich sludge produced from the Fenton oxidation process of pulp and paper mill wastewater contains high content of iron, leading to the dewatering difficulty of the mixed sludge. To solve this problem and reuse the iron？？rich sludge, an innovative approach, acidifing the iron？？rich sludge to leach out Fe3+ as a sludge conditioning agent, was proposed in this study. The composition of iron？？rich sludge was analyzed by elemental analyzer, X？？ray fluorescence spectrometry (XRF), and inductively coupled plasma optical emission spectrometry (ICP？？OES). The chemical phase and valence of iron were determined by X？？ray diffraction (XRD) and X？？ray photoelectron spectroscopy (XPS). The acidification conditions were optimized according to the iron leaching rate and acid consumption. The performance of the chemical conditioning agent obtained by this approach was estimated according to the decrease of sludge specific resistance, and was compared with the conditioning performance of FeCl3. The results indicate that the iron content is 39.32％ in the iron？？rich sludge from a pulp and paper mill, and ferrihydrite is the main form of ferric iron. The optimal condition for acidification at room temperature is that the mass ratio of sulfuric acid to dry sludge is 0.91 g/g and the reaction time is 180 min. Under the optimal condition, 57.24％ of the iron in the sludge can be leached into the solution. When the dosage of conditioning agents made from iron？？rich sludge reaches 3.45％ (by the mass of Fe) of dry sludge, the specific resistance of excess sludge can be reduced to 17.90％ of the initial value, which is quite close to the conditioning performance of FeCl3 at the same dosage. The results show that this proposed method is a feasible process for the recycling of the iron？？rich sludge from pulp and paper mills