Abstract: To address issues such as inclined tube clogging, floating misalignment, and frequent “pool pressure” (siltation overload) accidents, and to ensure the stable operation of the coal slime water treatment system while enhancing thickening efficiency, a comprehensive retrofitting scheme was implemented at the Changzhi Jingfang Guohua Coal Preparation Plant. The optimization involved replacing inclined tubes with inclined plates (lamella plates), installing a pneumatic-hydraulic combined agitation device, adding high-power sewage pumps, and incorporating a water replenishment dilution device. Post-retrofit results indicate that the average annual downtime decreased from 362 h to 80.5 h, and the circulating water concentration dropped from 20 g/L to 0.5 g/L. The clarification and thickening efficiency of the coal slime water were significantly improved, “pool pressure” accidents were effectively prevented, and both labor intensity and desilting safety risks were greatly reduced. The project generated an annual economic benefit of approximately 48.8169 million yuan. This comprehensive retrofit scheme, characterized by low investment and rapid returns, effectively resolves common problems such as clogging, siltation, and misalignment in thickeners, providing a valuable reference for similar challenges in other coal preparation enterprises.