This study reports on the impact of the curing conditions on the mechanical properties and leaching of inorganic polymer （IP） mortars made from a water quenched fayalitic slag. Three similar IP mortars were produced...This study reports on the impact of the curing conditions on the mechanical properties and leaching of inorganic polymer （IP） mortars made from a water quenched fayalitic slag. Three similar IP mortars were produced by mixing together slag, aggregate and activating solution, and cured in three different environments for 28 d： a） at 20℃ and relative humidity （RH） - 50% （T20RH50）, b） at 20℃and RH≥90% （T20RH90） and c） at 60℃ and RH - 20% （T60RH20）. Compressive strength （EN 196-1） varied between 19 MPa （T20RH50） and 31 MPa （T20RH90）. This was found to be attributed to the cracks formed upon curing. Geochemical modelling and two leaching tests were performed, the EA NEN 7375 tank test, and the BS EN 12457-1 single batch test. Results show that Cu, Ni, Pb, Zn andAs leaching occurred even at high pH, which varied between 10 and 11 in the tank test＇s leachates and between 12 and 12.5 in the single batch＇s leachates. Leaching values obtained were below the requirements for non-shaped materials of Flemish legislation for As, Cu and Ni in the single batch test.展开更多
A lot of iron-bearing slags were produced,and whose grade is much more than that of industrial iron ore grade.Chemical analysis and phase identification shows that the iron-bearing slag is amorphous,has fayalite main ...A lot of iron-bearing slags were produced,and whose grade is much more than that of industrial iron ore grade.Chemical analysis and phase identification shows that the iron-bearing slag is amorphous,has fayalite main phase,iron grade is 36.10%,and is difficult to recover iron from the slag.Thermodynamic calculation indicates that CO cannot reduce fayalite at high temperature and carbon direct reduction can be effective.Moreover,the reaction begins at 770 ℃ and the temperature can be reduced down to 500℃ when CaO is added.On this basis,a method is put forward to making direct enrichment of iron by taking carbon contained pellets to realize the rapid reduction of fayalite,and the direct reduction process were studied in this paper.Experiments show that xC/xO should be less than 1.5 for the need of reduction and carburization,and CaO and Al2O3 can spur the reduction of fayalite.On conditions that xC/xO is 1.2,metallization rate can be 77% when temperature is 1 250 ℃ and only carbon is added,and metallization rate can be 74% when temperature is 1 200 ℃ and only CaO is added.Moreover the addition of Al2O3 can get a higher metallization rate（10% or so） than usual as R is between 0.4 and 1.0.Under the optimized condition of R equals to 0.6,temperature of 1 250 ℃,slag melting point of 1 320 ℃,and time of 30 min,the metallization rate can reach 88.43%.展开更多
文摘This study reports on the impact of the curing conditions on the mechanical properties and leaching of inorganic polymer （IP） mortars made from a water quenched fayalitic slag. Three similar IP mortars were produced by mixing together slag, aggregate and activating solution, and cured in three different environments for 28 d： a） at 20℃ and relative humidity （RH） - 50% （T20RH50）, b） at 20℃and RH≥90% （T20RH90） and c） at 60℃ and RH - 20% （T60RH20）. Compressive strength （EN 196-1） varied between 19 MPa （T20RH50） and 31 MPa （T20RH90）. This was found to be attributed to the cracks formed upon curing. Geochemical modelling and two leaching tests were performed, the EA NEN 7375 tank test, and the BS EN 12457-1 single batch test. Results show that Cu, Ni, Pb, Zn andAs leaching occurred even at high pH, which varied between 10 and 11 in the tank test＇s leachates and between 12 and 12.5 in the single batch＇s leachates. Leaching values obtained were below the requirements for non-shaped materials of Flemish legislation for As, Cu and Ni in the single batch test.
基金Item Sponsored by National Science and Technology Support Program for 11th Five-Year Plan of China(2009BAB45B05)
文摘A lot of iron-bearing slags were produced,and whose grade is much more than that of industrial iron ore grade.Chemical analysis and phase identification shows that the iron-bearing slag is amorphous,has fayalite main phase,iron grade is 36.10%,and is difficult to recover iron from the slag.Thermodynamic calculation indicates that CO cannot reduce fayalite at high temperature and carbon direct reduction can be effective.Moreover,the reaction begins at 770 ℃ and the temperature can be reduced down to 500℃ when CaO is added.On this basis,a method is put forward to making direct enrichment of iron by taking carbon contained pellets to realize the rapid reduction of fayalite,and the direct reduction process were studied in this paper.Experiments show that xC/xO should be less than 1.5 for the need of reduction and carburization,and CaO and Al2O3 can spur the reduction of fayalite.On conditions that xC/xO is 1.2,metallization rate can be 77% when temperature is 1 250 ℃ and only carbon is added,and metallization rate can be 74% when temperature is 1 200 ℃ and only CaO is added.Moreover the addition of Al2O3 can get a higher metallization rate（10% or so） than usual as R is between 0.4 and 1.0.Under the optimized condition of R equals to 0.6,temperature of 1 250 ℃,slag melting point of 1 320 ℃,and time of 30 min,the metallization rate can reach 88.43%.
