Mineral carbonation is emerging as a reliable CO_(2) capture technology that can mitigate climate change.In lime-treated clayey soils,mineral carbonation occurs through the carbonation of free lime and cementitious pr...Mineral carbonation is emerging as a reliable CO_(2) capture technology that can mitigate climate change.In lime-treated clayey soils,mineral carbonation occurs through the carbonation of free lime and cementitious products derived from pozzolanic reactions.The kinetics of the reactions in lime-treated clayey soils are variable and depend primarily on soil mineralogy.The present study demonstrates the role of soil mineralogy in CO_(2) capture and the subsequent changes caused by carbon mineralization in terms of the unconfined compressive strength(UCS)of lime-treated soils during their service life.Three clayey soils(kaolin,bentonite,and silty clay)with different mineralogical characteristics were treated with 4%lime content,and the samples were cured in a controlled environment for 7 d,90 d,180 d,and 365 d.After the specified curing periods,the samples were exposed to CO_(2) in a carbonation cell for 7 d.The non-carbonated samples purged with N2 gas were used as a benchmark to compare the mechanical,chemical-mineralogical,and microstructure changes caused by carbonation reactions.Experimental investigations indicated that exposure to CO_(2) resulted in an average increase of 10%in the UCS of limetreated bentonite,whereas the strength of lime-treated kaolin and silty clay was reduced by an average of 35%.The chemical and microstructural analyses revealed that the precipitated carbonates effectively filled the macropores of the treated bentonite,compared to the inadequate cementation caused by pozzolanic reactions,resulting in strength enhancement.In contrast,strength loss in lime-treated kaolin and silty clay was attributed to the carbonation of cementitious phases and partly to the tensile stress induced by carbonate precipitation.In terms of carbon mineralization prospects,lime-treated kaolin exhibited maximum carbonation due to the higher availability of unreacted lime.The results suggest that,in addition to the increase in compressive strength,adequate calcium-bearing phases and macropores determine the efficiency of carbon mineralization in lime-treated clayey soils.展开更多
In tropical regions,heavy rainfall induces erosion and shallow landslides on road embankments.Cement-based stabilization methods,common in these regions,contribute to climate change due to their high carbon footprint....In tropical regions,heavy rainfall induces erosion and shallow landslides on road embankments.Cement-based stabilization methods,common in these regions,contribute to climate change due to their high carbon footprint.This study explored the potential application of coir fiber-reinforced laterite soil-bottom ash mixtures as embankment materials in the tropics.The objective is to enhance engineered embankment slopes'erosion resistance and stability while offering reuse options for industrial byproducts.This study examined various mix designs for unconfined compressive strength(UCS)and permeability,utilizing 30%bottom ash(BA)and 1%coir fiber(CF)with varying sizes ranging from 10 to 40 mm,6%lime,and laterite soil(LS),followed by microstructural analyses.The results demonstrate that the compressive strength increases as the CF length increases to 25 mm.In contrast,permeability increases continuously with increasing CF length.Lime-treated mixtures exhibit superior short-and long-term strength and reduce permeability owing to the formation of cementitious materials,as confirmed by microstructural analyses.A lab-scale slope box was constructed to evaluate the surface erosion of the stabilized laterite soil embankment.Based on the rainfall simulation results,the LS-BA-CF mixtures show better resistance to erosion and deformation compared to untreated LS,especially when lime is added to the top layer.This study provides insights into a sustainable and cost-effective approach for slope stabilization using BA and CF,offering a promising solution for tropical regions susceptible to surface erosion and landslides.展开更多
The machine learning models of multiple linear regression(MLR),support vector regression(SVR),and extreme learning ma-chine(ELM)and the proposed ELM models of online sequential ELM(OS-ELM)and OS-ELM with forgetting me...The machine learning models of multiple linear regression(MLR),support vector regression(SVR),and extreme learning ma-chine(ELM)and the proposed ELM models of online sequential ELM(OS-ELM)and OS-ELM with forgetting mechanism(FOS-ELM)are applied in the prediction of the lime utilization ratio of dephosphorization in the basic oxygen furnace steelmaking process.The ELM model exhibites the best performance compared with the models of MLR and SVR.OS-ELM and FOS-ELM are applied for sequential learning and model updating.The optimal number of samples in validity term of the FOS-ELM model is determined to be 1500,with the smallest population mean absolute relative error(MARE)value of 0.058226 for the population.The variable importance analysis reveals lime weight,initial P content,and hot metal weight as the most important variables for the lime utilization ratio.The lime utilization ratio increases with the decrease in lime weight and the increases in the initial P content and hot metal weight.A prediction system based on FOS-ELM is applied in actual industrial production for one month.The hit ratios of the predicted lime utilization ratio in the error ranges of±1%,±3%,and±5%are 61.16%,90.63%,and 94.11%,respectively.The coefficient of determination,MARE,and root mean square error are 0.8670,0.06823,and 1.4265,respectively.The system exhibits desirable performance for applications in actual industrial pro-duction.展开更多
A method to upgrade the iron grade in copper slag was proposed using lime to decompose Al_(2)O_(3)-containing fayalite melt(AFMT).Thermodynamic calculations indicated that adjusting the CaO/AFMT ratio can yield a resi...A method to upgrade the iron grade in copper slag was proposed using lime to decompose Al_(2)O_(3)-containing fayalite melt(AFMT).Thermodynamic calculations indicated that adjusting the CaO/AFMT ratio can yield a residual melt with a FeO concentration of 75−88 wt.%and produce Ca_(2)SiO_(4).In-situ observations suggested that the reaction was impeded in some way.Quenching experiments revealed that the initial reaction products consisted of calcium ferrite compounds and FeO−CaO melt.At the FeO−CaO melt/AFMT interface,Ca_(2)SiO_(4) particles precipitated,forming a dense Ca_(2)SiO_(4) film that significantly impeded mass transfer.Although trace amounts of Al_(2)O_(3) in AFMT temporarily enhanced mass transfer,they were insufficient to overcome this retardation effect.The decomposition reaction was far from achieving equilibrium,demonstrating a self-retardation effect.Measures must be implemented to eliminate this self-retardation effect and enhance the efficiency of reaction kinetics.展开更多
This paper presents and analyzes the results of a series of compaction,fragmentability and damage tests performed on an expansive overconsolidated clay treated with cement and lime.This clay was obtained from the urba...This paper presents and analyzes the results of a series of compaction,fragmentability and damage tests performed on an expansive overconsolidated clay treated with cement and lime.This clay was obtained from the urban site of Sidi-Hadjrès city(wilaya of M'sila,Algeria),where significant damages frequently appears in the road infrastructures,roadway systems and light structures.Tests results obtained show that the geotechnical parameters values deduced from these tests are concordant and confirm the evolutivity of this natural clay treated with composed Portland cement or extinct lime and compacted under optimum Proctor conditions.展开更多
The aim of this study was to evaluate the compressive strength of clay bricks and their stability to water absorption by inserting stabilizers such as lime and cement of 0%, 4%, 6%, 8%, 10%, 12% to 14%. Spectrometric ...The aim of this study was to evaluate the compressive strength of clay bricks and their stability to water absorption by inserting stabilizers such as lime and cement of 0%, 4%, 6%, 8%, 10%, 12% to 14%. Spectrometric analysis was used to characterize the various stabilizers and the clay used, and tests of resistance and water absorption were also carried out. The clay was found to be an aluminosilicate (15.55% to 17.17% Al2O3 and 42.12% to 44.15% SiO2). The lime contains 90.84% CaO and the cement has 17.80% SiO2, 3.46% Al2O3, 2.43% Fe2O3 and 58.47% CaO in the combined form of tricalcium silicate, dicalcium silicate, tricalcium aluminate and ferro-tetra calcium aluminate. The results showed that the insertion of locally available stabilizers (lime and cement) improved the strength of the material by almost 80% when the lime was increased from 0% to 14% for 14 days. For compressed cement, a 65% increase in strength was observed under the same conditions. Strength increases with drying time, with a 52% increase in strength at 28 days compared to 14 days. Furthermore, compressed cement bricks have a more compact structure, absorbing very little water (32%). In view of all these results, cement appears to be the best stabilizer, and compression improves compressive strength and reduces water absorption.展开更多
[Objective] The aim was to research effects of P fertilizer and lime on growth of Trrifolium repens, Chamaecrista rotundifolia and Macroptilium atropur- pureum, to provide references for cultivation of the three plant...[Objective] The aim was to research effects of P fertilizer and lime on growth of Trrifolium repens, Chamaecrista rotundifolia and Macroptilium atropur- pureum, to provide references for cultivation of the three plants. [Method] Pot experiments were conducted with Trrifolium repens, Charnaecrista rotundifolia and Macroptilium atropurpureum in 2010 in order to research effects of lime and P fer-tilizer mixture on growth of the plants in southern hilly acidic red soils. [Result] With lime amount fixed, application of P fertilizer would enhance plant height, total tiller number and dry matter. When P fertilizer was not applied, however, plant height of the three plants achieved the peak by lime at 1.4 g/kg which proved best for improvement of acidity of red soils. With P fertilizer at 200 mg/kg was applied, biomass of Trifolium repens and Macroptilium atropurpureum achieved the highest by lime at 2.1 g/kg, but total biomass of Chamaecrista rotundifolia was the highest by lime at 1.4 g/kg. [Conclusion] The research provides references for planting and production of Trifolium repens, Chamaecrista rotundifolia and Macroptilium atropur-pureum in southern hilly regions.展开更多
In this study, 13 strong-gluten wheat varieties screened by the Key Project of Modern Agricultural Industry Technology System "Study on Industrial Technology for Strong-gluten Wheat from Lime Concretion Black Soil Ar...In this study, 13 strong-gluten wheat varieties screened by the Key Project of Modern Agricultural Industry Technology System "Study on Industrial Technology for Strong-gluten Wheat from Lime Concretion Black Soil Area in the Huanghuai Wheat Region" were used as experimental materials to investigate their bread-making quality, noodle-making quality and other related characteristics. The results showed that more than half of the wheat varieties had better bread-making quality; the bread made from wheat with longer dough mixing time than 3.0 min had better texture, lighter color, and better taste. All these 13 strong-gluten wheat varieties showed good noodle-making quality in color, appearance, smoothness and taste; the differences between varieties were mainly found in palatability and viscoelasticity. Jimai 20, Xinong 979, Zhengmai 7698, Ji'nan 17 and Zhengmai 9023 exhibited excellent bread-making quality; Zhengmai 366, Jimai 20 and Xinong 979 displayed excellent noodle-making quality. Fresh dough sheets made from Zhengmai 366, Jimai 20 and Xinong 979 exhibited slight color variation within 24 h and high peak starch paste viscosity; dry and cooked noodles made from Zhengmai 366, Jimai 20 and Xinong 979 had good quality.展开更多
The electrical resistivity characteristics of cement soil and flyash lime soil are investigated in the laboratory and the field. It is shown that the electrical resistivities of the cement soil and flyash lime s...The electrical resistivity characteristics of cement soil and flyash lime soil are investigated in the laboratory and the field. It is shown that the electrical resistivities of the cement soil and flyash lime soil are sensitive to water content, degree of saturation and unconfined strength. The cement soil and flyash lime soil with higher water content, greater degree of saturation, lower unconfined strength has lower electrical resistivity. Electrical resistivity is also correlated with additives. Based on the tests, it is concluded that the electrical resistivity method is available for checking the effectiveness of the soil improvement by the cement soil and flyash lime soil mixing pile in terms of engineering practice.展开更多
To better understand the dynamic properties of expansive clay treated with lime, a series of laboratory tests were conducted using a dynamic triaxial test system. The influential factors, including moisture content, c...To better understand the dynamic properties of expansive clay treated with lime, a series of laboratory tests were conducted using a dynamic triaxial test system. The influential factors, including moisture content, confining pressure, vibration frequency, consolidation ratio, and cycle number on the dynamic characteristics were discussed. Experimental results indicate that specimens at low moisture contents tend to damage along the 30~ shear plane and they present brittle failure, while saturated specimens show swelling phenomenon and plastic failure. A redtiction in cohesion has been observed for unsaturated samples at large number of cycles, while it is opposite for the internal friction angle. For the saturated specimens, both the cohesion and internal friction angle decrease with increasing number of cycles.展开更多
In the present study,unconfined compressive strength(qu)values of two lime-treated soils(soil 1 and 2)with curing times of 28 d,90 d and 360 d were optimized.The influence of void/lime ratio was represented by the por...In the present study,unconfined compressive strength(qu)values of two lime-treated soils(soil 1 and 2)with curing times of 28 d,90 d and 360 d were optimized.The influence of void/lime ratio was represented by the porosity/volumetric lime content ratio(η/Liv)as the main parameter.η/Liv represents the volume of void influenced by compaction effort and lime volume.The evolution of qu was analyzed for each soil using the coefficient of determination as the optimization parameter.Aiming at providing adjustments to the mechanical resistance values,the η/Liv parameter was modified to η/LivC using the adjustment exponent C(to make qu-η/Liv variation rates compatible).The results show that with the decrease of η/LivC.qu increases potentially and the optimized values of C were 0.14-0.18.The mechanical resistance data show similar trends between qu and η/LivC for the studied silty soil-ground lime mixtures,which were cured at ambient temperature(23±2)℃ with different curing times of 28-360 d.Finally,optimized equations were presented using the normalized strengths and the proposed optimization model,which show 6% error and 95% acceptability on average.展开更多
Three identical model boxes were made from transparent plexiglass and angle iron. Using the method of sinking water and according to the sedimentary rhythm of saturated calcium carbonate (lime-mud) intercalated with...Three identical model boxes were made from transparent plexiglass and angle iron. Using the method of sinking water and according to the sedimentary rhythm of saturated calcium carbonate (lime-mud) intercalated with cohesive soil, calcites with particle sizes diameters of ≤ 5 μm, 10–15 μm and 23–30 μm as well as cohesive soil were sunk alternatively in water of three boxes to build three test models, each of which has a specific size of calcite. Pore water pressure gauges were buried in lime-mud layers at different depths in each model, and connected with a computer system to collect pore water pressures. By means of soil tests, physical property parameters and plasticity indices (Ip) were obtained for various grain-sized saturated lime-muds. The lime-muds with Ip ranging from 6.3 to 8.5 (lower than 10) are similar to liquid saturated silt in the physical nature, indicating that saturated silt can be liquefied once induced by a strong earthquake. One model cart was pushed quickly along the length direction of the model so that its rigid wheels collided violently with the stone stair, thus generating an artificial earthquake with seismic wave magnitude greater than VI degree. When unidirectional cyclic seismic load of horizontal compression-tension-shear was imposed on the soil layers in the model, enough great pore water pressure has been accumulated within pores of lime-mud, resulting in liquefaction of lime-mud layers. Meanwhile, micro-fractures formed in each soil layer provided channels for liquefaction dewatering, resulting in formation of macroscopic liquefaction deformation, such as liquefied lime-mud volcanoes, liquefied diapir structures, vein-like liquefied structures and liquefied curls, etc. Splendid liquefied lime-mud eruption lasted for two to three hours, which is similar to the sand volcano eruption induced by strong earthquake. However, under the same artificial seismic conditions, development of macroscopic liquefied structures in three experimental models varied in shape, depth and quantity, indicating that excess pore water pressure ratios at initial liquefaction stage and complete liquefaction varied with depth. With size increasing of calcite particle in lime-mud, liquefied depth and deformation extent increase accordingly. The simulation test verifies for the first time that strong earthquakes may cause violent liquefaction of saturated lime-mud composed of micron-size calcite particles, uncovering the puzzled issue whether seafloor lime-mud can be liquefied under strong earthquake. This study not only provides the latest simulation data for explaining the earthquake-induced liquefied deformations of saturated lime-mud and seismic sedimentary events, but also is of great significance for analysis of foundation stability in marine engineering built on the soft calcium carbonate layers in neritic environment.展开更多
Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and sal...Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and salt content were studied.The results show that because inshore saline soil has special engineering characteristic,more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.展开更多
Lime, which is a frequently used activating agent of fly ash (FA), has two main states: slaked lime and quick lime. We studied the effects of slaked lime and quick lime on activating FA, and discussed their kinetics. ...Lime, which is a frequently used activating agent of fly ash (FA), has two main states: slaked lime and quick lime. We studied the effects of slaked lime and quick lime on activating FA, and discussed their kinetics. The results show that slaked lime is more beneficial for activating FA than quick lime given the condition of equivalent CaO amount. The use of slaked lime has superiority in technology and economy on activating FA. Theoretical analysis revealed that the kinetic constant of the activation reaction using slaked lime is higher than using quick lime, credited to the better volume stability and fineness, and smaller water demand of slaked lime.展开更多
The hydration of quick lime and the sulfation of hydrated lime were carried out for verification of relationship between the reactivity of quick lime and the properties of hydrated lime as a sorbent. The effect of rea...The hydration of quick lime and the sulfation of hydrated lime were carried out for verification of relationship between the reactivity of quick lime and the properties of hydrated lime as a sorbent. The effect of reactivity of quick lime was investigated with the change of calcination temperature and time. Results obtained showed that the temperature rise during the hydration of quick limes varied from 31 to 69℃ with the variation of calcination temperature and time. The specific surface area and the sulfation ability of hydrated lime prepared by hydration of quick lime showed a proportional relationship with the reactivity of quick lime. The hydrated lime which was prepared by hydration of quick lime calcined at 1100℃ had the highest reactivity and showed 41.53 m^2/g of the specific surface area, 0.16 cm^3/g of the pore volume and 87% of the removal efficiency for SO2 removal,展开更多
Agricultural liming materials are often applied to the adjustment of soil acidity and the improvement of plant growth and microbial functionality.Relatively low-grade agricultural lime was found to contain up to 125 m...Agricultural liming materials are often applied to the adjustment of soil acidity and the improvement of plant growth and microbial functionality.Relatively low-grade agricultural lime was found to contain up to 125 mg/kg arsenic(As),which is above any fertilizing materials’ toxicity threshold limit.Several techniques were employed to determine the speciation of the arsenic.Results from microprobe analyses suggest that minor minerals such as black and brown dendrites are the source of high arsenic concentrations in the samples.X-ray fluorescence spectroscopy provided further information that ferrihydrite and crystalline goethite are responsible for hosting the high concentration of arsenic with Fe/As molar ratio in around 100.A five-step sequential extraction demon-展开更多
The efficacy of limestone sand and pelletized lime for remediation of soil acidity was compared in order to determine if limestone sand was a more cost-effective alternative to pelletized lime. Between fall of 2002 an...The efficacy of limestone sand and pelletized lime for remediation of soil acidity was compared in order to determine if limestone sand was a more cost-effective alternative to pelletized lime. Between fall of 2002 and spring 2003, two forested sites in Pennsylvania were clear cut and fenced. Pelletized lime and limestone sand were applied to separate 400-m2 plots within the sites at rates of 2170 kg·ha-1 and 4335 kg·ha-1, respectively. Two additional 400-m2 plots were used as controls. A paired before-after control-impact study design was used to assess changes in soil, soil solution, vegetation and biomass after lime application. Soil samples were collected from the Oi, Oe + Oa, and A horizons before and after lime application. Woody and herbaceous vegetation was harvested from 1-m2 sub-plots before and after liming and bi-weekly soil solution samples were collected for six months following lime application. Analysis of variance procedures were used to compare changes in the treatment plots over time. Changes in soil chemistry following lime application were comparable on the limestone sand and pelletized lime plots. There was a significant increase in exchangeable Mg and Mg saturation in the Oe + Oa horizon on all of the lime treatment plots relative to controls, but a greater percentage of applied Ca and Mg was exchangeable in the O-horizon in pelletized lime plots nine months after liming. Plant biomass did not increase on the lime treatment plots relative to the control one year post treatment. The majority of applied Ca and Mg from pelletized lime and limestone sand remained in the litter layer, with little movement into the A-horizon after one growing season. These results indicated that the application of limestone sand at two times the rate of pelletized lime produced comparable changes in soil and soil solution chemistry at a fraction of the cost.展开更多
In recent years, the need for low energy materials has become increasingly important. With government targets aiming to reduce carbon emissions by 80% by 2050, and the construction industry being responsible for 50% o...In recent years, the need for low energy materials has become increasingly important. With government targets aiming to reduce carbon emissions by 80% by 2050, and the construction industry being responsible for 50% of the UK's carbon emissions, it is of vital importance that positive changes are made. One of these changes is to reduce the carbon footprint of the materials used in construction. Lime mortar has been used for centuries, but since the arrival of cement, its use in modern construction has diminished, in part due to having lower compressive strengths than cement mortar. Air lime mortar, in particular, can be categorised as low energy due to the reabsorption of a significant amount of COE during the setting process: carbonation. The current study focuses on the impact of different types of aggregate (limestone and silicate) on air lime mortar strength. Previous research has found that higher strengths can be achieved with the use of limestone aggregate, but little is known about the reasons why. The research presented here looks at a microstructural analysis through use of SEM (scanning electron microscopy) in order to determine reasons behind the strength differences. At early stages of curing, there are clear differences at the interface of binder and aggregate.展开更多
基金partial financial support by the Women Leading IITM,IIT Madras,Chennai,India.
文摘Mineral carbonation is emerging as a reliable CO_(2) capture technology that can mitigate climate change.In lime-treated clayey soils,mineral carbonation occurs through the carbonation of free lime and cementitious products derived from pozzolanic reactions.The kinetics of the reactions in lime-treated clayey soils are variable and depend primarily on soil mineralogy.The present study demonstrates the role of soil mineralogy in CO_(2) capture and the subsequent changes caused by carbon mineralization in terms of the unconfined compressive strength(UCS)of lime-treated soils during their service life.Three clayey soils(kaolin,bentonite,and silty clay)with different mineralogical characteristics were treated with 4%lime content,and the samples were cured in a controlled environment for 7 d,90 d,180 d,and 365 d.After the specified curing periods,the samples were exposed to CO_(2) in a carbonation cell for 7 d.The non-carbonated samples purged with N2 gas were used as a benchmark to compare the mechanical,chemical-mineralogical,and microstructure changes caused by carbonation reactions.Experimental investigations indicated that exposure to CO_(2) resulted in an average increase of 10%in the UCS of limetreated bentonite,whereas the strength of lime-treated kaolin and silty clay was reduced by an average of 35%.The chemical and microstructural analyses revealed that the precipitated carbonates effectively filled the macropores of the treated bentonite,compared to the inadequate cementation caused by pozzolanic reactions,resulting in strength enhancement.In contrast,strength loss in lime-treated kaolin and silty clay was attributed to the carbonation of cementitious phases and partly to the tensile stress induced by carbonate precipitation.In terms of carbon mineralization prospects,lime-treated kaolin exhibited maximum carbonation due to the higher availability of unreacted lime.The results suggest that,in addition to the increase in compressive strength,adequate calcium-bearing phases and macropores determine the efficiency of carbon mineralization in lime-treated clayey soils.
文摘In tropical regions,heavy rainfall induces erosion and shallow landslides on road embankments.Cement-based stabilization methods,common in these regions,contribute to climate change due to their high carbon footprint.This study explored the potential application of coir fiber-reinforced laterite soil-bottom ash mixtures as embankment materials in the tropics.The objective is to enhance engineered embankment slopes'erosion resistance and stability while offering reuse options for industrial byproducts.This study examined various mix designs for unconfined compressive strength(UCS)and permeability,utilizing 30%bottom ash(BA)and 1%coir fiber(CF)with varying sizes ranging from 10 to 40 mm,6%lime,and laterite soil(LS),followed by microstructural analyses.The results demonstrate that the compressive strength increases as the CF length increases to 25 mm.In contrast,permeability increases continuously with increasing CF length.Lime-treated mixtures exhibit superior short-and long-term strength and reduce permeability owing to the formation of cementitious materials,as confirmed by microstructural analyses.A lab-scale slope box was constructed to evaluate the surface erosion of the stabilized laterite soil embankment.Based on the rainfall simulation results,the LS-BA-CF mixtures show better resistance to erosion and deformation compared to untreated LS,especially when lime is added to the top layer.This study provides insights into a sustainable and cost-effective approach for slope stabilization using BA and CF,offering a promising solution for tropical regions susceptible to surface erosion and landslides.
基金supported by the National Natural Science Foundation of China (No.U1960202).
文摘The machine learning models of multiple linear regression(MLR),support vector regression(SVR),and extreme learning ma-chine(ELM)and the proposed ELM models of online sequential ELM(OS-ELM)and OS-ELM with forgetting mechanism(FOS-ELM)are applied in the prediction of the lime utilization ratio of dephosphorization in the basic oxygen furnace steelmaking process.The ELM model exhibites the best performance compared with the models of MLR and SVR.OS-ELM and FOS-ELM are applied for sequential learning and model updating.The optimal number of samples in validity term of the FOS-ELM model is determined to be 1500,with the smallest population mean absolute relative error(MARE)value of 0.058226 for the population.The variable importance analysis reveals lime weight,initial P content,and hot metal weight as the most important variables for the lime utilization ratio.The lime utilization ratio increases with the decrease in lime weight and the increases in the initial P content and hot metal weight.A prediction system based on FOS-ELM is applied in actual industrial production for one month.The hit ratios of the predicted lime utilization ratio in the error ranges of±1%,±3%,and±5%are 61.16%,90.63%,and 94.11%,respectively.The coefficient of determination,MARE,and root mean square error are 0.8670,0.06823,and 1.4265,respectively.The system exhibits desirable performance for applications in actual industrial pro-duction.
基金supported by the National Natural Science Foundation of China (No.52121004)the National Science Fund for Distinguished Young Scholars (No.51825403)+2 种基金the Science and Technology Innovation Program of Hunan Province,China (No.2021RC3013)National Key R&D Program of China (No.2022YFC3901602)the Major Science and Technology Project of Gansu Province,China (No.21ZD4GD033)。
文摘A method to upgrade the iron grade in copper slag was proposed using lime to decompose Al_(2)O_(3)-containing fayalite melt(AFMT).Thermodynamic calculations indicated that adjusting the CaO/AFMT ratio can yield a residual melt with a FeO concentration of 75−88 wt.%and produce Ca_(2)SiO_(4).In-situ observations suggested that the reaction was impeded in some way.Quenching experiments revealed that the initial reaction products consisted of calcium ferrite compounds and FeO−CaO melt.At the FeO−CaO melt/AFMT interface,Ca_(2)SiO_(4) particles precipitated,forming a dense Ca_(2)SiO_(4) film that significantly impeded mass transfer.Although trace amounts of Al_(2)O_(3) in AFMT temporarily enhanced mass transfer,they were insufficient to overcome this retardation effect.The decomposition reaction was far from achieving equilibrium,demonstrating a self-retardation effect.Measures must be implemented to eliminate this self-retardation effect and enhance the efficiency of reaction kinetics.
文摘This paper presents and analyzes the results of a series of compaction,fragmentability and damage tests performed on an expansive overconsolidated clay treated with cement and lime.This clay was obtained from the urban site of Sidi-Hadjrès city(wilaya of M'sila,Algeria),where significant damages frequently appears in the road infrastructures,roadway systems and light structures.Tests results obtained show that the geotechnical parameters values deduced from these tests are concordant and confirm the evolutivity of this natural clay treated with composed Portland cement or extinct lime and compacted under optimum Proctor conditions.
文摘The aim of this study was to evaluate the compressive strength of clay bricks and their stability to water absorption by inserting stabilizers such as lime and cement of 0%, 4%, 6%, 8%, 10%, 12% to 14%. Spectrometric analysis was used to characterize the various stabilizers and the clay used, and tests of resistance and water absorption were also carried out. The clay was found to be an aluminosilicate (15.55% to 17.17% Al2O3 and 42.12% to 44.15% SiO2). The lime contains 90.84% CaO and the cement has 17.80% SiO2, 3.46% Al2O3, 2.43% Fe2O3 and 58.47% CaO in the combined form of tricalcium silicate, dicalcium silicate, tricalcium aluminate and ferro-tetra calcium aluminate. The results showed that the insertion of locally available stabilizers (lime and cement) improved the strength of the material by almost 80% when the lime was increased from 0% to 14% for 14 days. For compressed cement, a 65% increase in strength was observed under the same conditions. Strength increases with drying time, with a 52% increase in strength at 28 days compared to 14 days. Furthermore, compressed cement bricks have a more compact structure, absorbing very little water (32%). In view of all these results, cement appears to be the best stabilizer, and compression improves compressive strength and reduces water absorption.
基金Supported by National Science & Technology Pillar Program(2012BAD05B05)Special Fund for Agro-scientific Research in the Public Interest(201303139)+1 种基金国家科技支撑计划"中低产田改良科技工程"项目(2012BAD05B05)农业部公益性行业科研专项经费项目(201303139)资助
文摘[Objective] The aim was to research effects of P fertilizer and lime on growth of Trrifolium repens, Chamaecrista rotundifolia and Macroptilium atropur- pureum, to provide references for cultivation of the three plants. [Method] Pot experiments were conducted with Trrifolium repens, Charnaecrista rotundifolia and Macroptilium atropurpureum in 2010 in order to research effects of lime and P fer-tilizer mixture on growth of the plants in southern hilly acidic red soils. [Result] With lime amount fixed, application of P fertilizer would enhance plant height, total tiller number and dry matter. When P fertilizer was not applied, however, plant height of the three plants achieved the peak by lime at 1.4 g/kg which proved best for improvement of acidity of red soils. With P fertilizer at 200 mg/kg was applied, biomass of Trifolium repens and Macroptilium atropurpureum achieved the highest by lime at 2.1 g/kg, but total biomass of Chamaecrista rotundifolia was the highest by lime at 1.4 g/kg. [Conclusion] The research provides references for planting and production of Trifolium repens, Chamaecrista rotundifolia and Macroptilium atropur-pureum in southern hilly regions.
基金Supported by Earmarked Fund for Modern Agro-industry Technology Research System(CARS-03)Special Fund for Seed Industry Construction from Taishan Scholar FoundationNational Science and Technology Major Project for Genetic Improvement of Crop Quality~~
文摘In this study, 13 strong-gluten wheat varieties screened by the Key Project of Modern Agricultural Industry Technology System "Study on Industrial Technology for Strong-gluten Wheat from Lime Concretion Black Soil Area in the Huanghuai Wheat Region" were used as experimental materials to investigate their bread-making quality, noodle-making quality and other related characteristics. The results showed that more than half of the wheat varieties had better bread-making quality; the bread made from wheat with longer dough mixing time than 3.0 min had better texture, lighter color, and better taste. All these 13 strong-gluten wheat varieties showed good noodle-making quality in color, appearance, smoothness and taste; the differences between varieties were mainly found in palatability and viscoelasticity. Jimai 20, Xinong 979, Zhengmai 7698, Ji'nan 17 and Zhengmai 9023 exhibited excellent bread-making quality; Zhengmai 366, Jimai 20 and Xinong 979 displayed excellent noodle-making quality. Fresh dough sheets made from Zhengmai 366, Jimai 20 and Xinong 979 exhibited slight color variation within 24 h and high peak starch paste viscosity; dry and cooked noodles made from Zhengmai 366, Jimai 20 and Xinong 979 had good quality.
文摘The electrical resistivity characteristics of cement soil and flyash lime soil are investigated in the laboratory and the field. It is shown that the electrical resistivities of the cement soil and flyash lime soil are sensitive to water content, degree of saturation and unconfined strength. The cement soil and flyash lime soil with higher water content, greater degree of saturation, lower unconfined strength has lower electrical resistivity. Electrical resistivity is also correlated with additives. Based on the tests, it is concluded that the electrical resistivity method is available for checking the effectiveness of the soil improvement by the cement soil and flyash lime soil mixing pile in terms of engineering practice.
基金Supported by the National Natural Science Foundation of China(40772185)the Knowledge Innovation Program of Chinese Academy of Sciences(kzcx2-yw-150)
文摘To better understand the dynamic properties of expansive clay treated with lime, a series of laboratory tests were conducted using a dynamic triaxial test system. The influential factors, including moisture content, confining pressure, vibration frequency, consolidation ratio, and cycle number on the dynamic characteristics were discussed. Experimental results indicate that specimens at low moisture contents tend to damage along the 30~ shear plane and they present brittle failure, while saturated specimens show swelling phenomenon and plastic failure. A redtiction in cohesion has been observed for unsaturated samples at large number of cycles, while it is opposite for the internal friction angle. For the saturated specimens, both the cohesion and internal friction angle decrease with increasing number of cycles.
基金the Federal University of Technology-Parana, to the CAPES, CNPqFundacao Araucaria do Parana in Brazil for financial support
文摘In the present study,unconfined compressive strength(qu)values of two lime-treated soils(soil 1 and 2)with curing times of 28 d,90 d and 360 d were optimized.The influence of void/lime ratio was represented by the porosity/volumetric lime content ratio(η/Liv)as the main parameter.η/Liv represents the volume of void influenced by compaction effort and lime volume.The evolution of qu was analyzed for each soil using the coefficient of determination as the optimization parameter.Aiming at providing adjustments to the mechanical resistance values,the η/Liv parameter was modified to η/LivC using the adjustment exponent C(to make qu-η/Liv variation rates compatible).The results show that with the decrease of η/LivC.qu increases potentially and the optimized values of C were 0.14-0.18.The mechanical resistance data show similar trends between qu and η/LivC for the studied silty soil-ground lime mixtures,which were cured at ambient temperature(23±2)℃ with different curing times of 28-360 d.Finally,optimized equations were presented using the normalized strengths and the proposed optimization model,which show 6% error and 95% acceptability on average.
基金supported by the National Natural Science Foundation of China(NSFC-41272066)the Program for Changjiang Scholars & Innovative Research Team of the University of China(IRT-13075)
文摘Three identical model boxes were made from transparent plexiglass and angle iron. Using the method of sinking water and according to the sedimentary rhythm of saturated calcium carbonate (lime-mud) intercalated with cohesive soil, calcites with particle sizes diameters of ≤ 5 μm, 10–15 μm and 23–30 μm as well as cohesive soil were sunk alternatively in water of three boxes to build three test models, each of which has a specific size of calcite. Pore water pressure gauges were buried in lime-mud layers at different depths in each model, and connected with a computer system to collect pore water pressures. By means of soil tests, physical property parameters and plasticity indices (Ip) were obtained for various grain-sized saturated lime-muds. The lime-muds with Ip ranging from 6.3 to 8.5 (lower than 10) are similar to liquid saturated silt in the physical nature, indicating that saturated silt can be liquefied once induced by a strong earthquake. One model cart was pushed quickly along the length direction of the model so that its rigid wheels collided violently with the stone stair, thus generating an artificial earthquake with seismic wave magnitude greater than VI degree. When unidirectional cyclic seismic load of horizontal compression-tension-shear was imposed on the soil layers in the model, enough great pore water pressure has been accumulated within pores of lime-mud, resulting in liquefaction of lime-mud layers. Meanwhile, micro-fractures formed in each soil layer provided channels for liquefaction dewatering, resulting in formation of macroscopic liquefaction deformation, such as liquefied lime-mud volcanoes, liquefied diapir structures, vein-like liquefied structures and liquefied curls, etc. Splendid liquefied lime-mud eruption lasted for two to three hours, which is similar to the sand volcano eruption induced by strong earthquake. However, under the same artificial seismic conditions, development of macroscopic liquefied structures in three experimental models varied in shape, depth and quantity, indicating that excess pore water pressure ratios at initial liquefaction stage and complete liquefaction varied with depth. With size increasing of calcite particle in lime-mud, liquefied depth and deformation extent increase accordingly. The simulation test verifies for the first time that strong earthquakes may cause violent liquefaction of saturated lime-mud composed of micron-size calcite particles, uncovering the puzzled issue whether seafloor lime-mud can be liquefied under strong earthquake. This study not only provides the latest simulation data for explaining the earthquake-induced liquefied deformations of saturated lime-mud and seismic sedimentary events, but also is of great significance for analysis of foundation stability in marine engineering built on the soft calcium carbonate layers in neritic environment.
基金Project(05YFSYSF00300) supported by the Natural Science Foundation of Tianjin
文摘Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and salt content were studied.The results show that because inshore saline soil has special engineering characteristic,more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.
基金Funded by Natural Science Foundation of China under the grant No. 50672137
文摘Lime, which is a frequently used activating agent of fly ash (FA), has two main states: slaked lime and quick lime. We studied the effects of slaked lime and quick lime on activating FA, and discussed their kinetics. The results show that slaked lime is more beneficial for activating FA than quick lime given the condition of equivalent CaO amount. The use of slaked lime has superiority in technology and economy on activating FA. Theoretical analysis revealed that the kinetic constant of the activation reaction using slaked lime is higher than using quick lime, credited to the better volume stability and fineness, and smaller water demand of slaked lime.
基金supported by grants-in-aid for the National Research Laboratory Program from MOST/KOSEF (No. R0A-2003-000-10320)partially supported by grants-in-aid for the National Core Research Center Program from MOST/KOSEF (No. R15-2006-022-01001-0)
文摘The hydration of quick lime and the sulfation of hydrated lime were carried out for verification of relationship between the reactivity of quick lime and the properties of hydrated lime as a sorbent. The effect of reactivity of quick lime was investigated with the change of calcination temperature and time. Results obtained showed that the temperature rise during the hydration of quick limes varied from 31 to 69℃ with the variation of calcination temperature and time. The specific surface area and the sulfation ability of hydrated lime prepared by hydration of quick lime showed a proportional relationship with the reactivity of quick lime. The hydrated lime which was prepared by hydration of quick lime calcined at 1100℃ had the highest reactivity and showed 41.53 m^2/g of the specific surface area, 0.16 cm^3/g of the pore volume and 87% of the removal efficiency for SO2 removal,
文摘Agricultural liming materials are often applied to the adjustment of soil acidity and the improvement of plant growth and microbial functionality.Relatively low-grade agricultural lime was found to contain up to 125 mg/kg arsenic(As),which is above any fertilizing materials’ toxicity threshold limit.Several techniques were employed to determine the speciation of the arsenic.Results from microprobe analyses suggest that minor minerals such as black and brown dendrites are the source of high arsenic concentrations in the samples.X-ray fluorescence spectroscopy provided further information that ferrihydrite and crystalline goethite are responsible for hosting the high concentration of arsenic with Fe/As molar ratio in around 100.A five-step sequential extraction demon-
文摘The efficacy of limestone sand and pelletized lime for remediation of soil acidity was compared in order to determine if limestone sand was a more cost-effective alternative to pelletized lime. Between fall of 2002 and spring 2003, two forested sites in Pennsylvania were clear cut and fenced. Pelletized lime and limestone sand were applied to separate 400-m2 plots within the sites at rates of 2170 kg·ha-1 and 4335 kg·ha-1, respectively. Two additional 400-m2 plots were used as controls. A paired before-after control-impact study design was used to assess changes in soil, soil solution, vegetation and biomass after lime application. Soil samples were collected from the Oi, Oe + Oa, and A horizons before and after lime application. Woody and herbaceous vegetation was harvested from 1-m2 sub-plots before and after liming and bi-weekly soil solution samples were collected for six months following lime application. Analysis of variance procedures were used to compare changes in the treatment plots over time. Changes in soil chemistry following lime application were comparable on the limestone sand and pelletized lime plots. There was a significant increase in exchangeable Mg and Mg saturation in the Oe + Oa horizon on all of the lime treatment plots relative to controls, but a greater percentage of applied Ca and Mg was exchangeable in the O-horizon in pelletized lime plots nine months after liming. Plant biomass did not increase on the lime treatment plots relative to the control one year post treatment. The majority of applied Ca and Mg from pelletized lime and limestone sand remained in the litter layer, with little movement into the A-horizon after one growing season. These results indicated that the application of limestone sand at two times the rate of pelletized lime produced comparable changes in soil and soil solution chemistry at a fraction of the cost.
文摘In recent years, the need for low energy materials has become increasingly important. With government targets aiming to reduce carbon emissions by 80% by 2050, and the construction industry being responsible for 50% of the UK's carbon emissions, it is of vital importance that positive changes are made. One of these changes is to reduce the carbon footprint of the materials used in construction. Lime mortar has been used for centuries, but since the arrival of cement, its use in modern construction has diminished, in part due to having lower compressive strengths than cement mortar. Air lime mortar, in particular, can be categorised as low energy due to the reabsorption of a significant amount of COE during the setting process: carbonation. The current study focuses on the impact of different types of aggregate (limestone and silicate) on air lime mortar strength. Previous research has found that higher strengths can be achieved with the use of limestone aggregate, but little is known about the reasons why. The research presented here looks at a microstructural analysis through use of SEM (scanning electron microscopy) in order to determine reasons behind the strength differences. At early stages of curing, there are clear differences at the interface of binder and aggregate.