Electro-flocculation And Chemical Flocculation For Silicon Removal Applications

With the continuous development of the country’s industrialization process,the problem of ecological environment damage has become increasingly serious.Water is an important foundation for human survival and an important support for the development of industrial industries,but the scarcity of water resources also puts forward higher requirements for the sustainable development of industrialization.Taking the recycling of coal gasification ash water as the starting point,aiming at the problem of pipeline scaling in the process of coal gasification ash water recycling,the causes of the scaling were analyzed,and the method of electroflocculation + chemical flocculation to remove silicon was proposed.The factors affecting the removal of silicon by electroflocculation and chemical flocculation were analyzed separately through small experiments,and liquid sodium metaaluminate was prepared.The effects of different electrode plates,p H,energization time,current density,and electrode plate spacing on the silicon removal effect of electroflocculation were analyzed.Different chemical dosage,p H,stirring speed,and reaction time affect the effect of chemical flocculation on silicon removal.In order to maximize the benefits of the two flocculation methods,combined with the actual situation of the site,the electro-flocculation and chemical flocculation were combined in the experiment.When the electro-flocculation and solid sodium metaaluminate acted synergistically,the silicon removal rate reached 89.7%,and the turbidity of the produced water was 5 NTU.the following.FESEM,FETEM and EDS analysis were carried out on the precipitation of the produced water,and it was judged that aluminum and silicon formed crystalline precipitation,which verified that the silicon in the gasification ash water was removed in the form of precipitation.In the experimental stage of the small test,the self-made liquid sodium metaaluminate was made.After the experimental analysis of the influencing factors of silicon removal by the self-made liquid sodium metaaluminate,the experiment was compared with the solid sodium metaaluminate.The silicon rate can reach 90.3%.Comparing the economic benefits of solid sodium metaaluminate and liquid sodium metaaluminate,it can save 2,600 yuan per ton of solid sodium metaaluminate with the same silicon removal effect.The results of the small-scale experiment were verified by the pilot-scale dynamic experiment.After adjusting the equipment parameters,the equipment ran stably for half a month.The silicon concentration of the water sample was reduced to below 50mg/L,the turbidity was within 5NTU,and the average silicon removal rate was 82.9%.The results of the small-scale experiment were verified by the pilot-scale dynamic experiment.After adjusting the equipment parameters,the equipment ran stably for half a month.The silicon concentration of the water sample was reduced to below 50mg/L,the turbidity was within 5NTU,and the average silicon removal rate was 82.9%,reaching the standard of gasification grey water recycling.