硫酸钙结疤清洗方法研究  

Study on CaSO_4 scabs removal techniques

作　　者：曹彩虹[1] 于增盛 曹战国 Cao Caihong;Yu Zengsheng;Cao Zhanguo(Tangshan Sanyou Group Co.,Ltd.,Tangshan 063305,China)

机构地区：[1]唐山三友集团有限公司,河北唐山063305

出　　处：《无机盐工业》2018年第9期57-59,共3页Inorganic Chemicals Industry

摘　　要：主要介绍碱法生产氯化钙过程中设备结疤的清洗方法。碱法制取氯化钙的原料来自纯碱蒸氨废液,其上清液经过自然摊晒提浓生成高浓度钙液,再经蒸发、干燥制成片状或球状氯化钙。因蒸发器对钙液进行再次提浓时受钙液中硫酸根、碳酸根等的影响,在设备管道中形成坚硬、致密的硫酸钙、碳酸钙结疤,如不及时清除将导致热损失增大,严重时造成生产系统停车、瘫痪。通过分析结疤特性,选取4种处理方法——高压水清洗法、盐洗法、乙二胺四乙酸二钠(EDTA)络合法、碱洗法,通过实验对比了4种方法的优缺点,以寻求最佳的处理方法。实验结果表明,选用碱洗的方法,即用2.5 mol/L的碳酸钠溶液将硫酸钙结疤转化成碳酸钙,再用质量分数为5%的稀盐酸与碳酸钙进行复分解反应,可对结疤进行有效清除。Scabs removal techniques for CaCl2 production using soda ash by-product are introduced.The CaCl2 production′s raw materials come from the waste residue generated during ammonia distilling process in the soda ash production.After tedd-ing process,the supernatant layer of the waste residue is concentrated.The following evaporation and drying processes crysta-llize CaCl2 slices and particles,eventually.Due to the SO42-and CO32-existing in the re-condense process,hard and dense CaSO4 and CaCO3 scabs forming in the equipments and pipes happens a lot.Heat loss increasing,even the whole production system being forced to shut down may be occur if the scabs are not to be removed in time.By analyzing characteristics of the scabs,there come up 4 methods for scabs removal.They are high pressure water cleaning,salt wash cleaning,EDTA complex-ation and Na2CO3 solution cleaning.These methods are chosen and compared for a best solution result,experimentally.It is re-vealed that 2.5 mol/L Na2CO3 solution reacts with CaSO4 to form CaCO3.Then the scabs can be effectively removed by the double decomposition reaction occurs between 5%(mass fraction)dilute hydrochloric acid and CaCO3,which indicates that Na2CO3 solution cleaning is an effective method for scabs removal.

关 键 词：氯化钙 硫酸钙结疤 碱洗 

分 类 号：TQ132.32[化学工程—无机化工]