The Pretreatment Experiment Study Of Reverse Osmosis Technology For Tailings Water

The project focuses on deep-recycle and treatment of tailings water from Baogang, which is constituted of water discharged from concentrator, rare earth and other units'wastewater. all the toxic substance in water seriously endanger the circumstance and resident's health around.Due to the water's quality verify a lot and the hardness is very high, maximal to higher than 3000mg/L. the ferric ion, sulfate, manganese ion, fluoride and Chloride ion abounded. RO technique is selected to treat the tailings water. The key question of the RO technique is the water quality, therefore, the pre-treatment of the water is the priority.After the analysis of water quality, soften-coagulation-sedimentation + filtration process is adopted for the pretreatment. The process is the main research object of the project.The paper first introduces the statistic experiment, which is constituted by two parts. One is softening experiment, by using the soft reagent like lime and soda. Single factors experiment and orthogonal experiment was performed individually, the experiment indicates that softening process by using lime and soda can lower the hardness efficiently. The rate can reach 85%. Total hardness decrease from 3300mg/L to 400mg/L. The other is coagulation test:Basing on the soft experiment result, individual add PAC and adding PAC and PAM together was tried, and it shows that the individual one is not as efficient as the together one, the water's Turbidity is as low as 2.0NTU.The project also investigate the dynamic test, which include two parts, one is soften-coagulation-sedimentation dynamic test. Guiding by the outcome of static test, we add drug such like lime, soda and PAC, PAM. The result tells us that the hardness removal rate still can reach 85%. At the same time, the process can remove the ferric ion, sulfate, manganese ion, fluoride, etc. I obtain the best drug dosage. The second part is whole pretreatment process's test. After the experiment, we can come to a conclusion that the water can meet reverse osmosis membrane's requirements by pre-treating. RO technique, by deep-treatment of the tailings water, can decrease the pollution also save the water resources by recycling the tailings water, Which is an obvious benefit to economy and society.