Preparation Of Modified Steel Slag Ceramsite And Its Application In Soil Infiltration System

In recent years,the amount of sewage discharged has increased,resulting in the pollution of large areas of lake water.One of the most serious water pollution problems is the eutrophication of water bodies.Phosphorus is a decisive factor influencing the eutrophication of water bodies.As a kind of steelmaking waste,steel slag has a huge annual output in China,and its utilization efficiency is low.Improper handling can cause environmental pollution.Steel slag has good adsorption and phosphorus removal performance.In recent years,more and more scholars have carried out modification research on steel slag and applied it to wastewater treatment,which better reflects the utilization value of steel slag.This paper takes Tangshan converter steel slag as the research object,studies its modification conditions,and further determines the optimum process conditions of phosphorus removal.The data were fitted to isothermal adsorption models,kinetic adsorption models,and further through characterization experiments to analyze the mechanism of phosphate removal by modified steel slag ceramsite.The details are as follows:1.Study on modification of steel slag.Firstly,the modifiers added in the modified steel slag were screened.By comparing the phosphorus removal rates of four metal oxides and four different calcium forms of compounds,CaO was determined as the best modifier.Further study of steel slag,modifiers,montmorillonite and starch ratio was finally determined to be45%:15%:25%:15%.The calcined conditions of the ceramic granules were optimized,and the optimum calcination temperature was determined to be 1000°C.and the calcination time was 30 min.2.Analyze the static adsorption test results,and study the effect of modified steel slag ceramite dosage,adsorption time,solution pH,and initial phosphorus concentration on the effect of phosphorus removal,and confirm that the modified steel slag ceramsite is suitable for treatment concentration lower than 2.0 Phosphorus-containing waste water of mg/L has the best removal effect at a pH of 11 and the dosage of modified slag ceramics is 10 g/L.When the adsorption time reaches 120 min,the removal rate reaches 92.3%.3.Data analysis of phosphorus removal from modified steel slag ceramsite indicates that the adsorption process of modified steel slag ceramsite is more in line with Langmuir isotherm adsorption and Lagergren quasi-secondary kinetics adsorption.Therefore,the modified steel slag ceramsite adsorption belongs to monolayer chemisorption.he specific surface area of the steel slag before and after modification increases by 2.3421 m~2/g,and the pore volume increases by 2.2125 cm~3/g.The main component of the modified steel slag ceramsite is calcium silicate,and the main product after phosphorus absorption is calcium phosphate,indicating that the modified steel slag The calcium ions in the ceramsite absorb phosphate ions to form precipitates,thereby removing phosphate from the wastewater.4.Test simulation of soil infiltration system,select Baoding river water,hydraulic load is0.03m~3/(m~2·d),water quality COD,ammonia nitrogen,total nitrogen,total phosphorus mean were 100.79mg/L,2.03mg/L,6.59 respectively Mg/L,1.25 mg/L.When the modified steel slag ceramisite was used as a matrix,the mean values?of effluent were 21.12mg/L,0.53mg/L,1.98mg/L,and 0.09mg/L respectively,indicating that the modified steel slag ceramsite is more suitable as the matrix of the soil infiltration system.