The effect of sulfur addition/solids content(SA/SC)ratio on heavy metals(e.g.copper,zinc and lead)obtained from mine tailings by indigenous sulfur-oxidizing bacteria was studied,and the changes in the chemical forms o...The effect of sulfur addition/solids content(SA/SC)ratio on heavy metals(e.g.copper,zinc and lead)obtained from mine tailings by indigenous sulfur-oxidizing bacteria was studied,and the changes in the chemical forms of heavy metals after bioleaching were explored.The results show that the solubilization of metals is significantly influenced by SA/SC ratio,and SA/SC ratio of 2.50 is found to be the best for bacterial activity and metal solubilization among six SA/SC ratios tested(such as 1.00,1.33,1.50,1.67,2.00 and 2.50)under the chosen experimental conditions.The pH decreases fast and the maximum solubilizations of copper and zinc are respectively 81.76% and 84.35% while that of lead only reaches 40.36%.After bioleaching,the chemical forms of heavy metals have changed.The metals remained in mine tailings are mainly found in residual fractions,which is harmless to the surrounding environment.展开更多
Estimation of stressses within the tailings slurry during self-weight consolidation is a critical issue for cost-effective barricade design and efficient backfill planning in underground mine stopes.This process requi...Estimation of stressses within the tailings slurry during self-weight consolidation is a critical issue for cost-effective barricade design and efficient backfill planning in underground mine stopes.This process requires a good understanding of self-weight consolidation behaviors of the tailings slurry within practical stopes,where many factors can have significant effects on the consolidation,including drainage condition and cement addition.In this paper,the prepared tailings slurry with different cement contents(0,4.76wt%,and 6.25wt%)was poured into1.2 m-high columns,which allowed three drainage scenarios(undrained,partial lateral drainage near the bottom part,and full lateral drainage boundaries)to investigate the effects of drainage condition and cement addition on the consolidation behavior of the tailings slurry.The consolidation behavior was analyzed in terms of pore water pressure(PWP),settlement,volume of drainage water,and residual water content.The results indicate that increasing the length of the drainage boundary or cement content aids in PWP dissipation.In addition,constructing an efficient drainage boundary was more favorable to PWP dissipation than increasing cement addition.The final stable PWP on the column floor was not sensitive to cement addition.The final settlement of uncemented tailings slurry was independent of drainage conditions,and that of cemented tailings slurry decreased with the increase in cement addition.Notably,more pore water can drain out from the cemented tailings slurry than the uncemented tailings slurry during consolidation.展开更多
This paper presents findings of an experiment for the comparison of sugar concentration in extracted juice of fresh fruit to that of commercially-bottled 100% fruit juice with a “no sugar added” attribute. The goal ...This paper presents findings of an experiment for the comparison of sugar concentration in extracted juice of fresh fruit to that of commercially-bottled 100% fruit juice with a “no sugar added” attribute. The goal of the study was to determine if the sugar content of bottled 100% fruit juice with a “no sugar added” label is equivalent to that of extracted juices of fresh fruits. The reported study was performed to address the potential concern that commercially-bottled 100% fruit juices with “no sugar added” may contain higher sugar content than extracted juice of fresh fruit. The fruit juices that were tested included apple, grapefruit, orange, pineapple, pomegranate, red grape and white grape. All bottled juices and fresh fruits were purchased in Toledo, Ohio, USA during the winter of 2012. The fresh fruits were juiced and three samples were tested for sugar concentration using a Brix refractometer. The same testing protocol was also applied to the bottled 100% fruit juice. Application of the Mann-Whitney test on the experimental data demonstrated no statistically significant difference (p > 0.05). The results suggested that the sugar content in the commercially bottled 100% fruit juice with the “no sugar added” label is an accurate representation of sugar content in the freshly-extracted juice of the corresponding fruit.展开更多
Low-cost thermal insulation porous ceramics with uniform pore diameter and low bulk density were prepared with soda-ash dregs and felsic tailings.We investigated the effect of temperature,foaming agent,fluxing agent,A...Low-cost thermal insulation porous ceramics with uniform pore diameter and low bulk density were prepared with soda-ash dregs and felsic tailings.We investigated the effect of temperature,foaming agent,fluxing agent,Al_(2)O_(3)and CaO content on the pore structure and crystal phase of porous ceramics.The effect of Ca^(2+)in soda-ash dregs on the preparation of quartz-feldspar based porous ceramics was studied.The results showed that the contribution of Ca^(2+)to the preparation of porous ceramics in this system was mainly to accelerate the Si-O bond fracture and reduce the sintering temperature at the initial stage of sintering,which destroyed the needle-like feldspar in the high temperature melt and reduced the melt viscosity,thus reduced the foaming resistance and promoted the porous products with uniform pore size distribution.The Ca^(2+)content on the high side can participate in the formation of crystals in sintering.The generated needle-like diopside and augite,which have small length-diameter ratio,will negligibly change in the viscosity of melt at high temperatures,and their inhibition effect on pores is not as good as that of feldspar with large length-diameter ratio,resulting in the merger and collapse of pores.But the increase of diopside and augite can improve the compressive strength of porous products to some extent.Porous ceramic products containing needle-like feldspar phase can be prepared by using two kinds of solid waste,which can improve the compressive strength of the products and reduce the raw material cost and energy consumption while comprehensively utilizing the double solid waste.The optimal product has a bulk density of 0.45 g/cm^(3),a compressive strength of 3.17 MPa,and a thermal conductivity of 0.11 W/(m·K).展开更多
铁尾矿机制砂被广泛应用于混凝土中,然而部分铁尾矿机制砂中硫含量过高,可能会造成混凝土膨胀开裂。本文配制了不同硫含量的铁尾矿机制砂混凝土,研究硫含量对混凝土工作性能、力学性能和耐久性能的影响规律,并采用X R D、压汞、SEM等微...铁尾矿机制砂被广泛应用于混凝土中,然而部分铁尾矿机制砂中硫含量过高,可能会造成混凝土膨胀开裂。本文配制了不同硫含量的铁尾矿机制砂混凝土,研究硫含量对混凝土工作性能、力学性能和耐久性能的影响规律,并采用X R D、压汞、SEM等微观测试分析了铁尾矿机制砂中硫含量对混凝土性能的影响机理。结果表明:铁尾矿机制砂中硫含量的增加显著影响混凝土的工作性能;硫含量为2%的C30铁尾矿机制砂混凝土早期强度最高,养护龄期在3 d和7 d时,混凝土抗压强度比空白组分别提升了14.4%、11.7%,其抗碳化性能和抗氯离子扩散能力均优于其他硫含量的混凝土。少量的硫化物可以提供充足的SO42-,激发水泥混合材水化反应的进行;含硫量过高则会导致混凝土中的A Ft和石膏等膨胀性晶体增加,混凝土内部产生较大应力,造成混凝土开裂,对后期强度发展不利,对于铁尾矿机制砂混凝土,硫含量不宜超过4%。展开更多
基金Project(11JJ2031)supported by the Key Project of Natural Fund of Hunan Province,ChinaProject(2009SK3029)supported by the Plan of Hunan Provincial Science and Technology Department,China
文摘The effect of sulfur addition/solids content(SA/SC)ratio on heavy metals(e.g.copper,zinc and lead)obtained from mine tailings by indigenous sulfur-oxidizing bacteria was studied,and the changes in the chemical forms of heavy metals after bioleaching were explored.The results show that the solubilization of metals is significantly influenced by SA/SC ratio,and SA/SC ratio of 2.50 is found to be the best for bacterial activity and metal solubilization among six SA/SC ratios tested(such as 1.00,1.33,1.50,1.67,2.00 and 2.50)under the chosen experimental conditions.The pH decreases fast and the maximum solubilizations of copper and zinc are respectively 81.76% and 84.35% while that of lead only reaches 40.36%.After bioleaching,the chemical forms of heavy metals have changed.The metals remained in mine tailings are mainly found in residual fractions,which is harmless to the surrounding environment.
基金financially supported by the Young Scientist Project of the National Key Research and Development Program of China (No.2021YFC2900600)the Beijing Nova Program (No.20220484057)financial support from China Scholarship Council under Grant CSC No.202110300001。
文摘Estimation of stressses within the tailings slurry during self-weight consolidation is a critical issue for cost-effective barricade design and efficient backfill planning in underground mine stopes.This process requires a good understanding of self-weight consolidation behaviors of the tailings slurry within practical stopes,where many factors can have significant effects on the consolidation,including drainage condition and cement addition.In this paper,the prepared tailings slurry with different cement contents(0,4.76wt%,and 6.25wt%)was poured into1.2 m-high columns,which allowed three drainage scenarios(undrained,partial lateral drainage near the bottom part,and full lateral drainage boundaries)to investigate the effects of drainage condition and cement addition on the consolidation behavior of the tailings slurry.The consolidation behavior was analyzed in terms of pore water pressure(PWP),settlement,volume of drainage water,and residual water content.The results indicate that increasing the length of the drainage boundary or cement content aids in PWP dissipation.In addition,constructing an efficient drainage boundary was more favorable to PWP dissipation than increasing cement addition.The final stable PWP on the column floor was not sensitive to cement addition.The final settlement of uncemented tailings slurry was independent of drainage conditions,and that of cemented tailings slurry decreased with the increase in cement addition.Notably,more pore water can drain out from the cemented tailings slurry than the uncemented tailings slurry during consolidation.
文摘This paper presents findings of an experiment for the comparison of sugar concentration in extracted juice of fresh fruit to that of commercially-bottled 100% fruit juice with a “no sugar added” attribute. The goal of the study was to determine if the sugar content of bottled 100% fruit juice with a “no sugar added” label is equivalent to that of extracted juices of fresh fruits. The reported study was performed to address the potential concern that commercially-bottled 100% fruit juices with “no sugar added” may contain higher sugar content than extracted juice of fresh fruit. The fruit juices that were tested included apple, grapefruit, orange, pineapple, pomegranate, red grape and white grape. All bottled juices and fresh fruits were purchased in Toledo, Ohio, USA during the winter of 2012. The fresh fruits were juiced and three samples were tested for sugar concentration using a Brix refractometer. The same testing protocol was also applied to the bottled 100% fruit juice. Application of the Mann-Whitney test on the experimental data demonstrated no statistically significant difference (p > 0.05). The results suggested that the sugar content in the commercially bottled 100% fruit juice with the “no sugar added” label is an accurate representation of sugar content in the freshly-extracted juice of the corresponding fruit.
基金Supported by the National Natural Science Foundation of China(No.51674161)Major Basic Research Projects of Shandong Province Natural Science Foundation(No.ZR2017ZC0735)+1 种基金Open Topic of Key Laboratory of Gold Mineralization Processes and Resource Utilization Subordinated to the Ministry of Land and Resources and Key Laboratory of Metallogenic Geological Process and Resources Utilization in Shandong Province(No.Kfkt201812)Research on Precious Metal Mineral Achievement Integration and Tailings Comprehensive Utilization in Shandong Province(Shandong Geological Exploration Document:[2018]No.10)。
文摘Low-cost thermal insulation porous ceramics with uniform pore diameter and low bulk density were prepared with soda-ash dregs and felsic tailings.We investigated the effect of temperature,foaming agent,fluxing agent,Al_(2)O_(3)and CaO content on the pore structure and crystal phase of porous ceramics.The effect of Ca^(2+)in soda-ash dregs on the preparation of quartz-feldspar based porous ceramics was studied.The results showed that the contribution of Ca^(2+)to the preparation of porous ceramics in this system was mainly to accelerate the Si-O bond fracture and reduce the sintering temperature at the initial stage of sintering,which destroyed the needle-like feldspar in the high temperature melt and reduced the melt viscosity,thus reduced the foaming resistance and promoted the porous products with uniform pore size distribution.The Ca^(2+)content on the high side can participate in the formation of crystals in sintering.The generated needle-like diopside and augite,which have small length-diameter ratio,will negligibly change in the viscosity of melt at high temperatures,and their inhibition effect on pores is not as good as that of feldspar with large length-diameter ratio,resulting in the merger and collapse of pores.But the increase of diopside and augite can improve the compressive strength of porous products to some extent.Porous ceramic products containing needle-like feldspar phase can be prepared by using two kinds of solid waste,which can improve the compressive strength of the products and reduce the raw material cost and energy consumption while comprehensively utilizing the double solid waste.The optimal product has a bulk density of 0.45 g/cm^(3),a compressive strength of 3.17 MPa,and a thermal conductivity of 0.11 W/(m·K).
