Abstract: This study systematically examines the effects of polyacrylamide (PAM) and polyethylene oxide (PEO) as filter aids on the dewatering performance of limonite ore, and explores their underlying mechanisms of action through comprehensive experimental analysis. The solid-liquid separation behavior was evaluated using bench-scale sedimentation tests, vacuum-assisted dewatering experiments, and pilot-scale plate-and-frame filter press filtration. The samples were comprehensively characterized by Zeta potential analysis, Fourier-transform infrared (FTIR) spectroscopy, laser-diffraction particle-size distribution measurements, and high-resolution scanning electron microscopy (SEM). The results showed that PAM and PEO could reduce the moisture content of filter cake. Under optimal dosage (PAM 20 g/t, PEO 10 g/t) and acidic conditions (pH=2), the filter cake moisture contents decreased to 17.42% and 16.55%, respectively. In addition, under simulated industrial conditions with a filter press pressure of 0.8 MPa, the moisture contents further decreased to 16.85% (PAM) and 15.88% (PEO), which were 0.57 and 1.54 percentage points lower than that of the raw ore, demonstrating a remarkable improvement in dewatering efficiency. Mechanistic analysis revealed that PAM promoted particle flocculation primarily through electrostatic repulsion and adsorption bridging, whereas PEO improved the filtration performance by forming surface complexes and enhancing particle hydrophobicity. These findings indicated that PEO outperformed PAM in limonite dewatering. PEO can not only achieve lower moisture content at lower dosage, but also obtain higher dehydration efficiency and more stable filtration performance. This study provides theoretical basis and technical support for efficient dehydration of limonite. By improving the dehydration efficiency, the research helps to significantly reduce energy consumption and operational costs, while improving the overall production efficiency. The findings lay a foundation for future scientific research and large-scale industrial application of limonite dewatering, and also provide a new way to optimize the beneficiation process.

Key words: limonite, filter aid, polyacrylamide, polyethylene oxide, dehydration, moisture content

摘要： 本工作研究了聚丙烯酰胺(PAM)和聚氧化乙烯(PEO)作为助滤剂对褐铁矿脱水效果的影响及其作用机制。通过沉降试验、脱水试验和板框压滤试验，结合Zeta电位、红外光谱、粒度分布和扫描电镜分析，系统评估了两种药剂的脱水性能与机理。结果表明，PAM和PEO均能显著降低滤饼含水率，在最佳用量(PAM 20 g/t, PEO 10 g/t)和酸性条件(pH=2)下，滤饼含水率分别降至17.42%和16.55%。当采用板框压滤模拟工业过程、压榨压力为0.8 MPa时，滤饼含水率进一步降至16.85% (PAM)和15.88% (PEO)。机理分析表明，PAM主要通过静电斥力和吸附架桥促进颗粒絮凝，PEO则通过形成络合物和增强疏水性改善过滤性能。本研究为褐铁矿高效脱水提供了理论依据和技术支撑，有助于降低烧结球团过程的能耗，提升生产效率。

关键词: 褐铁矿, 助滤剂, 聚丙烯酰胺, 聚氧化乙烯, 脱水, 含水率