The slurry settling characteristics are the most important to design a thickener in process industries. In this work, the iron ore slurry from the screw classifier overflow was used for the settling study. It was obse...The slurry settling characteristics are the most important to design a thickener in process industries. In this work, the iron ore slurry from the screw classifier overflow was used for the settling study. It was observed that the original slurry exhibited a low settling velocity and a turbid supernatant during the settling process. Commercial flocculating agents with anionic, cationic, and nonionic characters were used to improve the settling behavior of suspensions, which were added into the slurry at different ranges of slurry pH values, respectively. The settling results show that the use of flocculants increase the settling rate by several times. Compared with the cationic and non-ionic flocculants, the anionic flocculant is more effective in enhancing the slurry settling rate. The small dose of the anionic flocculant is found to be more effective, but the other flocculants are less effective even at higher dosages. The simulation of an industrial thickener was carried out based on the laboratory settling data, and the appropriate design and selection parameters of the industrial thickener were estimated.展开更多
Mg-7.6% Al （in mass fraction） alloy matrix composites reinforced with different volume fractions of nano- crystalline Al3Cas particles were synthesized by powder metallurgy, and the effect of the volume fraction of ...Mg-7.6% Al （in mass fraction） alloy matrix composites reinforced with different volume fractions of nano- crystalline Al3Cas particles were synthesized by powder metallurgy, and the effect of the volume fraction of reinforcement on the mechanical properties was studied. Room temperature compression test reveals considerable improvement on mechanical properties as compared to unreinforced matrix. The compressive strength increases from 683 MPa for unre- inforced alloy matrix to about 767 and 823 MPa for the samples having 20 and 40 vol% of reinforcement, respectively, while retaining appreciable plastic deformation ranging between 12 and 24%. The specific strength of the composites increased significantly, demonstrating the effectiveness of the low-density AlaCas reinforcement.展开更多
Al-7Si-0.5Mg-0.5Cu alloy specimens have been fabricated by selective laser melting(SLM).In this study,the effects of solution treatment,quenching,and artifi cial aging on the microstructural evolution,as well as mecha...Al-7Si-0.5Mg-0.5Cu alloy specimens have been fabricated by selective laser melting(SLM).In this study,the effects of solution treatment,quenching,and artifi cial aging on the microstructural evolution,as well as mechanical and wear properties,have been investigated.The as-prepared samples show a heterogeneous cellular microstructure with two different cell sizes composed ofα-Al and Si phases.After solution-treated and quenched(SQ)heat treatment,the cellular microstructure disappears,and coarse and lumpy Si phase precipitates and a rectangular Cu-rich phase were observed.Subsequent aging after solution-treated and quenched(SQA)heat treatment causes the formation of nanosized Cu-rich precipitates.The asprepared SLMs sample has good mechanical properties and wear resistance(compressive yield strength:215±6 MPa and wear rate 2×10^(-13)m^(3)/m).The SQ samples with lumpy Si particles have the lowest strength of 167±13 MPa and the highest wear rate of 6.18×10^(1-13)m^(3)/m.The formation of nanosized Cu-rich precipitates in the SQA samples leads to the highest compressive yield strength of 233±6 MPa and a good wear rate of 5.06×10^(-13)m^(3)/m.展开更多
文摘The slurry settling characteristics are the most important to design a thickener in process industries. In this work, the iron ore slurry from the screw classifier overflow was used for the settling study. It was observed that the original slurry exhibited a low settling velocity and a turbid supernatant during the settling process. Commercial flocculating agents with anionic, cationic, and nonionic characters were used to improve the settling behavior of suspensions, which were added into the slurry at different ranges of slurry pH values, respectively. The settling results show that the use of flocculants increase the settling rate by several times. Compared with the cationic and non-ionic flocculants, the anionic flocculant is more effective in enhancing the slurry settling rate. The small dose of the anionic flocculant is found to be more effective, but the other flocculants are less effective even at higher dosages. The simulation of an industrial thickener was carried out based on the laboratory settling data, and the appropriate design and selection parameters of the industrial thickener were estimated.
文摘Mg-7.6% Al （in mass fraction） alloy matrix composites reinforced with different volume fractions of nano- crystalline Al3Cas particles were synthesized by powder metallurgy, and the effect of the volume fraction of reinforcement on the mechanical properties was studied. Room temperature compression test reveals considerable improvement on mechanical properties as compared to unreinforced matrix. The compressive strength increases from 683 MPa for unre- inforced alloy matrix to about 767 and 823 MPa for the samples having 20 and 40 vol% of reinforcement, respectively, while retaining appreciable plastic deformation ranging between 12 and 24%. The specific strength of the composites increased significantly, demonstrating the effectiveness of the low-density AlaCas reinforcement.
基金the Guangdong Basic and Applied Basic Research Foundation(2020A1515110869)Shenzhen International Cooperation Research(GJHZ20190822095418365)+2 种基金the Natural Science Foundation of SZU(Grant No.2019040)Additional support was provided by the European Regional Development Fund(ASTRA6-6)Jürgen Eckert is grateful for the support from the Ministry of Science and Higher Education of the Russian Federation in the framework of the Increase Competitiveness Program of MISiS(Support project for young research engineers,Project No.K2-2020-046)。
文摘Al-7Si-0.5Mg-0.5Cu alloy specimens have been fabricated by selective laser melting(SLM).In this study,the effects of solution treatment,quenching,and artifi cial aging on the microstructural evolution,as well as mechanical and wear properties,have been investigated.The as-prepared samples show a heterogeneous cellular microstructure with two different cell sizes composed ofα-Al and Si phases.After solution-treated and quenched(SQ)heat treatment,the cellular microstructure disappears,and coarse and lumpy Si phase precipitates and a rectangular Cu-rich phase were observed.Subsequent aging after solution-treated and quenched(SQA)heat treatment causes the formation of nanosized Cu-rich precipitates.The asprepared SLMs sample has good mechanical properties and wear resistance(compressive yield strength:215±6 MPa and wear rate 2×10^(-13)m^(3)/m).The SQ samples with lumpy Si particles have the lowest strength of 167±13 MPa and the highest wear rate of 6.18×10^(1-13)m^(3)/m.The formation of nanosized Cu-rich precipitates in the SQA samples leads to the highest compressive yield strength of 233±6 MPa and a good wear rate of 5.06×10^(-13)m^(3)/m.
