碱液净化系统设计探讨

针对当前冷轧清洗段采用磁过滤仅能去除碱液中的铁磁性物质,碱液中非铁磁性或者灰分成分难以被有效去除而导致机组吨钢碱液消耗过大,碱液排放废水量大的问题,结合碱液清洗工艺,分析了带入到碱液中悬浮物的成分和特性,利用碱液中悬浮物成分的铁磁性、沉降性、颗粒性、黏性和絮凝性、起泡性等特性,根据工程实践,提出有针对性地采用不同的工艺单元对碱液进行净化的方案,包括采用常规的棒链式和转毂式磁滤器、改进型的高磁过滤器、斜板沉淀槽和压榨机,微滤装置、冷却搅拌静置除油装置,分离并及时去除碱液中的悬浮物和油分,提升碱液清洁度,减少碱液的提前排放,提高碱液的使用效率,实现清洗段碱洗工序的节能减排。

Discussion on design of alkali purification system

At present, there are many problems in cleaning section of cold rolling unit, such as high alkali consumption per ton of steel and large discharge of alkali waste water,which caused by the fact that magnetic filtration can only remove ferromagnetic substances in lye, while non-ferromagnetic and ash components cannot be effectively removed. In view of the current problems,combined with alkali cleaning process, some properties of suspended solids in lye were analyzed, such as ferromagnetism, sedimentation, granularity, viscosity, flocculation and foaming. Based on these analysis and engineering practice, the purification schemes of lye for different alkali cleaning process were proposed. By using some devices such as conventional bar chain type magnetic filter, hub type magnetic filter, improved high magnetic filter, inclined plate precipitation tank, the micro-filter device and cooling & stirring & standing oil removal device, the suspended matter and oil in lye could be separated and removed in time, the cleanliness of lye was improved, the advance discharge of lye was reduced, the use efficiency of lye was improved. The energy saving and emission reduction of alkaline cleaning process was realized.