Study On Adsorption Of Heavy Metal Ions On Blast Furnace Slag And Its Curing Performance

Blast furnace slag is a kind of solid waste produced in the process of blast furnace ironmaking.The main structure of blast furnace slag is the network structure formed by silicon oxygen tetrahedron[Si O₄]^4-through mutual connection under the action of polymerization,which has good adsorption effect on heavy metal ions in waste water.High slag adsorbing heavy metal ions can also be used as cement admixture,which greatly improves the utilization price of this industrial waste Value.In this paper,the adsorption performance and mechanism of heavy metal ions on blast furnace slag were studied,and the solidification performance of heavy metal ions on blast furnace slag as cement admixture was explored,which provided theoretical technology and technical support for resource utilization of blast furnace slag.Based on the amount of blast furnace slag,p H value of waste water,adsorption time and temperature,the adsorption efficiency of copper,cadmium and lead ions was determined.The optimal conditions of adsorption reaction were determined,and the adsorption isothermal model and adsorption kinetics were discussed.The results show that the more the amount of blast furnace slag is,the higher the p H value of wastewater,the longer the adsorption time and the higher the temperature,the greater the removal rate of heavy metals.Under the best reaction conditions of orthogonal test,the removal rates of copper,cadmium and lead ions can reach 99.9%,78.9%and100.0%respectively.The adsorption of copper,cadmium and lead ions by blast furnace slag conforms to the Langmuir adsorption isotherm model Quasi second order dynamic equation.The influence of the composition and structure of blast furnace slag on the adsorption of copper ions was studied from the aspects of the composition of blast furnace slag,vitreous structure,specific surface area,pore structure and zeta potential.The results show that when the calcium magnesium ratio of blast furnace slag is 8,the content of glass phase is 62.54%,the content of Q¹silicon oxygen tetrahedron in the glass structure is 87.64%,and the zeta potential is-18.64mv,the adsorption effect of copper ion is the best,and the removal rate is 100.0%..The curing and hydration properties of the composite cementitious material of absorbing heavy metal blast furnace slag and cement were studied.The results show that in the leaching method of GB/T 7023-2011,the leaching amount of copper ion on the solidified surface of blast furnace slag cement composite cementitious material in each leaching period is less than 1mg/L.Different amount of blast furnace slag has better effect on solidifying copper ion.In the leaching method of HJ/T300-2007,the amount of cupric ion leached by composite cementitious material solidified by different blast furnace slag is less than 1 mg/L after curing for 28 days,reaching the discharge standard of copper ion specified in the“surface water environmental quality standard”.