水洗处理赤泥初步脱碱

赤泥是氧化铝冶炼工业生产过程中排放的固体废弃物，是一种严重的碱性污染源。实验采用不同温度（20、55、75、95 ℃）的水分别对强碱性赤泥进行洗涤。结果表明，首次洗涤所得洗涤液的质量浓度较高，6次洗涤液的平均质量浓度在2.44~2.72 g/L，其中冷水洗涤赤泥所得的溶液质量浓度最高。每次洗涤得到的洗涤液的pH变化不大。不同温度的水洗涤赤泥，回收碱的效率相差不大，前3次洗涤碱的回收量占总量的70%以上。其中，冷水洗涤赤泥回收碱的质量最多。经过6次洗涤后，每克赤泥中最终回收的氢氧化钠的质量最高达8.18 mg。

Preliminary dealkalization of red mud by washing process

Red mud,a solid waste residue of alumina refinery industrial production,is a serious pollution source because of its strong basicity.Experiments of washing strong alkaline red mud with water of different temperatures(20,55,75,95 ℃) were carried out.Results showed that the mass concentration of initial washing solution was relatively higher,average mass concentration of 6-time′s washing solutions was at 2.44~2.72 g/L,and mass concentration of the solution washed by cold water(20 ℃) was the highest.pH of each washing liquid had little change.Recovery efficiency of alkali was not changed significantly with washing water of different temperatures and the alkali recovery amount of the former 3 time′s washing accounted for more than 70% of the total.Among them,recovery amount of alkali with the cold water washing was the highest.After 6 time′s washing,the mass of recoveried sodium hydroxide was as high as 8.18 mg from every gram of red mud.