赤泥沉降槽Ａ３钢盖板的腐蚀是保温层上的抹面灰泥吸水渗水，使硅藻土保温砖经常处于潮湿状态，其浸出液是碱性强电解质，Ａ３钢在此环境中发生电化学腐蚀．腐蚀产物是以Ｆｅ３Ｏ４、Ｆｅ２Ｏ３和ＦｅＯ（ＯＨ）为主铁的氧化物和氢氧化物．建议采用致密的石灰抹面并在抹面上施加煤焦油沥青覆盖层防止渗水． Red mud settling tank A3 corrosion of the steel cover plate is mortar on the insulation water absorption and water absorption, diatomite insulation brick is often in a wet state, the leaching solution is alkaline electrolyte, A3 steel electrochemical corrosion occurred in this environment . The corrosion products are oxides and hydroxides mainly composed of Fe3O4, Fe2O3 and FeO (OH). It is advisable to apply a dense lime plaster and apply a coal tar pitch over the plaster to prevent seepage.