To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 4...To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 400 kg/m3 were tested. Ground granulated blast-furnace slag (GGBS) as a source material was activated by the following two types of alkali activators: 10% Ca(OH)2 and 4% Mg(NO3)2, and 2.5% Ca(OH)2 and 6.5% Na2SiO3. The main test parameters were water-to-binder (W/B) ratio and the substitution level (RFA) of fly ash (FA) for GGBS. Test results revealed that the dry density of AA GGBS foamed concrete was independent of the W/B ratio an RFA, whereas the compressive strength increased with the decrease in W/B ratio and with the increase in RFA up to 15%, beyond which it decreased. With the increase in the W/B ratio, the amount of macro capillaries and artificial air pores increased, which resulted in the decrease of compressive strength. The magnitude of the environmental loads of the AA GGBS foamed concrete is independent of the W/B ratio and RFA. The largest reduction percentage was found in the photochemical oxidation potential, being more than 99%. The reduction percentage was 87% - 93% for the global warming potential, 81% - 84% for abiotic depletion, 79% - 84% for acidification potential, 77% - 85% for eutrophication potential, and 73% - 83% for human toxicity potential. Ultimately, this study proved that the developed AA GGBS foamed concrete has a considerable promise as a sustainable construction material for nonstructural element.展开更多
A new electric arc furnace (EAF) steelmaking process with increasing hot metal charging ratio and improving slagging regime simultaneously was developed and applied in a 50 t electric arc furnace for more than a year ...A new electric arc furnace (EAF) steelmaking process with increasing hot metal charging ratio and improving slagging regime simultaneously was developed and applied in a 50 t electric arc furnace for more than a year at No.1 Steelmaking Plant of Shanxi Taigang Stainless Corporation Limited. The essential fact of the new EAF steelmaking process was to charge hot metal in two portions or steps: firstly, 35wt%-40wt% hot metal was pretreated by blowing oxygen in a specially designed reactor for decar-burization and improving hot metal temperature and melting premelted slag; secondly, 30wt% hot metal was charged into EAF with high basicity refining slags from ladle furnace (LF)-vacuum degassing furnace (VD) refining process. The results show that the hot metal charging ratio can reach to about 65wt%-70wt% for the new EAF steelmaking process; meanwhile, the tap-to-tap time of a 50 t EAF can shorten by 5-10 min, the electricity consumption can decrease by 35-50 kW·h/t, the lime consumption can reduce by 10.5 kg/t of molten steel, and the content of harmful heavy metals in molten steel can be easily controlled to less than the upper limits of aimed steel specification or grade compared with the traditional EAF steelmaking process. In addition, the dephosphorization ability shows a slight strengthening, however, a small degree of lessening for desulphurization ability is observed for the new EAF steelmaking process, but the weakness of desulphurization ability cannot become an obstacle to its further application since a stronger desulphurization ability can be achieved during secondary refining of LF coupled with VD after EAF steelmaking process.展开更多
Surface tension of calcium aluminate refining slag was measured by the Slide method at 1823 K.Based on different levels of the MgO content and the mass ratio of CaO to Al_2O_3,the effects of MgO content and the mass r...Surface tension of calcium aluminate refining slag was measured by the Slide method at 1823 K.Based on different levels of the MgO content and the mass ratio of CaO to Al_2O_3,the effects of MgO content and the mass ratio of CaO to Al_2O_3 on surface tension were investigated.The results indicate that surface tension decreased with increasing MgO content(from 0 to 4.86%),followed by an increase with further increasing MgO content up to 11.33%.The trend that surface tension changed with the mass ratio of CaO to Al_2O_3 was the same as the trend that surface tension changed with the MgO content.The surface tension was varied from 0.617 N/m to 0.710 N/m,for the mass ratio of CaO to Al_2O_3 varying between 0.60 and 1.28.An attempt was made to estimate surface tension of CaO-Al_2O_3-MgO slag and its sub-system,and the application showed that the model worked well.展开更多
The liquid iron containing elements Nb,Mn and Si has been equilibratedwith MgO-SiO<sub>2</sub>-MnO slag melts at 1600℃ in a Mo wire-wound resistance furnace with aduration of 4h.The oxygen activities in l...The liquid iron containing elements Nb,Mn and Si has been equilibratedwith MgO-SiO<sub>2</sub>-MnO slag melts at 1600℃ in a Mo wire-wound resistance furnace with aduration of 4h.The oxygen activities in liquid iron were measured with oxygen sensors.Usingthe known equilibrium constants of concerning reactions and the oxygen activities in liquidiron,the activities of components in the slag melts can be calculated.It was found that the par-tition ratios of Nb.Mn and Si have a close linear relationship with α<sub>FeO</sub> in logarithmicscale.The dependence of Nb partition ratio on mole fractions of the slag components was al-so obtained.展开更多
With the proper choice of the ion speciespresent in the Panzhihua blast furnace slag,the sulphur partition ratio was calculated basedon the ionization theory of the slag. It canbe concluded that TiO<sub>2</su...With the proper choice of the ion speciespresent in the Panzhihua blast furnace slag,the sulphur partition ratio was calculated basedon the ionization theory of the slag. It canbe concluded that TiO<sub>2</sub> reacts as an acidtc oxideand the Panzhihua ore or concentrate cannotbe treated as a semi-self-fluxing ore.展开更多
The distribution behavior of residual elements copper and tin between FeO rich slag and iron solution was investigated under the condition of an induction furnace. The results indicate that a part of copper and tin is...The distribution behavior of residual elements copper and tin between FeO rich slag and iron solution was investigated under the condition of an induction furnace. The results indicate that a part of copper and tin is incidently oxidized when oxygen is blasted into bath to react with iron element. The distribution ratio of copper and tin between slag and metal is about 0.1. Phenomena of Cu and Sn elements segregation and accumulation in slag were observed by means of EPMA analysis. The distribution ratio of copper and tin between slag and metal may descend with increasing of CaO content in slag.展开更多
In order to obtain better carbonation effect,extraction behavior of slag batch is necessary to study.Relevant parameters like selective extraction yield were originally discussed.The relationship between selective ext...In order to obtain better carbonation effect,extraction behavior of slag batch is necessary to study.Relevant parameters like selective extraction yield were originally discussed.The relationship between selective extraction yield and conversion ratio was systemically focused on.The results show that alkaline earth metal conversion ratio is changed with leaching time and NH4Cl concentration by first order exponential,and the maximum conversion for calcium keeps about 68% at 120 min in 0.4 mol/L NH4Cl solution,while leaching temperature and particle size have a linear effect on conversion ratio.Selective extraction yield of calcium is more than 93%,and the value of Mg is less than 5%.Apparent layer bands of silicon and calcium appear in the surface area through morphology detection of slag after leaching,and the case for 38-75 μm slag batch is more obvious than 75-150 μm slag and slag with larger particle size when leaching in 0.4 mol/L NH4Cl solution for 90 min at 60 ℃.展开更多
文摘To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 400 kg/m3 were tested. Ground granulated blast-furnace slag (GGBS) as a source material was activated by the following two types of alkali activators: 10% Ca(OH)2 and 4% Mg(NO3)2, and 2.5% Ca(OH)2 and 6.5% Na2SiO3. The main test parameters were water-to-binder (W/B) ratio and the substitution level (RFA) of fly ash (FA) for GGBS. Test results revealed that the dry density of AA GGBS foamed concrete was independent of the W/B ratio an RFA, whereas the compressive strength increased with the decrease in W/B ratio and with the increase in RFA up to 15%, beyond which it decreased. With the increase in the W/B ratio, the amount of macro capillaries and artificial air pores increased, which resulted in the decrease of compressive strength. The magnitude of the environmental loads of the AA GGBS foamed concrete is independent of the W/B ratio and RFA. The largest reduction percentage was found in the photochemical oxidation potential, being more than 99%. The reduction percentage was 87% - 93% for the global warming potential, 81% - 84% for abiotic depletion, 79% - 84% for acidification potential, 77% - 85% for eutrophication potential, and 73% - 83% for human toxicity potential. Ultimately, this study proved that the developed AA GGBS foamed concrete has a considerable promise as a sustainable construction material for nonstructural element.
文摘A new electric arc furnace (EAF) steelmaking process with increasing hot metal charging ratio and improving slagging regime simultaneously was developed and applied in a 50 t electric arc furnace for more than a year at No.1 Steelmaking Plant of Shanxi Taigang Stainless Corporation Limited. The essential fact of the new EAF steelmaking process was to charge hot metal in two portions or steps: firstly, 35wt%-40wt% hot metal was pretreated by blowing oxygen in a specially designed reactor for decar-burization and improving hot metal temperature and melting premelted slag; secondly, 30wt% hot metal was charged into EAF with high basicity refining slags from ladle furnace (LF)-vacuum degassing furnace (VD) refining process. The results show that the hot metal charging ratio can reach to about 65wt%-70wt% for the new EAF steelmaking process; meanwhile, the tap-to-tap time of a 50 t EAF can shorten by 5-10 min, the electricity consumption can decrease by 35-50 kW·h/t, the lime consumption can reduce by 10.5 kg/t of molten steel, and the content of harmful heavy metals in molten steel can be easily controlled to less than the upper limits of aimed steel specification or grade compared with the traditional EAF steelmaking process. In addition, the dephosphorization ability shows a slight strengthening, however, a small degree of lessening for desulphurization ability is observed for the new EAF steelmaking process, but the weakness of desulphurization ability cannot become an obstacle to its further application since a stronger desulphurization ability can be achieved during secondary refining of LF coupled with VD after EAF steelmaking process.
基金Project(51204115)supported by the National Natural Science Foundation of ChinaProject(BK20130308)supported by the Basic Research Program of Jiangsu Province,ChinaProject(2014M561710)supported by China Postdoctoral Science Foundation
文摘Surface tension of calcium aluminate refining slag was measured by the Slide method at 1823 K.Based on different levels of the MgO content and the mass ratio of CaO to Al_2O_3,the effects of MgO content and the mass ratio of CaO to Al_2O_3 on surface tension were investigated.The results indicate that surface tension decreased with increasing MgO content(from 0 to 4.86%),followed by an increase with further increasing MgO content up to 11.33%.The trend that surface tension changed with the mass ratio of CaO to Al_2O_3 was the same as the trend that surface tension changed with the MgO content.The surface tension was varied from 0.617 N/m to 0.710 N/m,for the mass ratio of CaO to Al_2O_3 varying between 0.60 and 1.28.An attempt was made to estimate surface tension of CaO-Al_2O_3-MgO slag and its sub-system,and the application showed that the model worked well.
文摘The liquid iron containing elements Nb,Mn and Si has been equilibratedwith MgO-SiO<sub>2</sub>-MnO slag melts at 1600℃ in a Mo wire-wound resistance furnace with aduration of 4h.The oxygen activities in liquid iron were measured with oxygen sensors.Usingthe known equilibrium constants of concerning reactions and the oxygen activities in liquidiron,the activities of components in the slag melts can be calculated.It was found that the par-tition ratios of Nb.Mn and Si have a close linear relationship with α<sub>FeO</sub> in logarithmicscale.The dependence of Nb partition ratio on mole fractions of the slag components was al-so obtained.
文摘With the proper choice of the ion speciespresent in the Panzhihua blast furnace slag,the sulphur partition ratio was calculated basedon the ionization theory of the slag. It canbe concluded that TiO<sub>2</sub> reacts as an acidtc oxideand the Panzhihua ore or concentrate cannotbe treated as a semi-self-fluxing ore.
文摘The distribution behavior of residual elements copper and tin between FeO rich slag and iron solution was investigated under the condition of an induction furnace. The results indicate that a part of copper and tin is incidently oxidized when oxygen is blasted into bath to react with iron element. The distribution ratio of copper and tin between slag and metal is about 0.1. Phenomena of Cu and Sn elements segregation and accumulation in slag were observed by means of EPMA analysis. The distribution ratio of copper and tin between slag and metal may descend with increasing of CaO content in slag.
基金Project(2006BAE03A07)supported by National Key Technology Research and Development Program of 11th Five-year Plan of China
文摘In order to obtain better carbonation effect,extraction behavior of slag batch is necessary to study.Relevant parameters like selective extraction yield were originally discussed.The relationship between selective extraction yield and conversion ratio was systemically focused on.The results show that alkaline earth metal conversion ratio is changed with leaching time and NH4Cl concentration by first order exponential,and the maximum conversion for calcium keeps about 68% at 120 min in 0.4 mol/L NH4Cl solution,while leaching temperature and particle size have a linear effect on conversion ratio.Selective extraction yield of calcium is more than 93%,and the value of Mg is less than 5%.Apparent layer bands of silicon and calcium appear in the surface area through morphology detection of slag after leaching,and the case for 38-75 μm slag batch is more obvious than 75-150 μm slag and slag with larger particle size when leaching in 0.4 mol/L NH4Cl solution for 90 min at 60 ℃.
