The adsorption of methyl orange onto ultrafine coal powder （UCP） and modified ultrafine coal powder （MUCP） from aqueous solutions were studied, in which the influence of contact time, dosage, temperature, pH, and ...The adsorption of methyl orange onto ultrafine coal powder （UCP） and modified ultrafine coal powder （MUCP） from aqueous solutions were studied, in which the influence of contact time, dosage, temperature, pH, and methyl orange concentration in the solution were investigated. The adsorption kinetics of methyl orange by UCP and MUCP can be described by the Lagergren first-order and pseudo second-order kinetic models, respectively. The adsorption isotherms of methyl orange onto MUCP at 303, 313 and 323 K follow the Freundlich and Langmuir isotherm equation. Values of △G^0 for methyl orange adsorption onto MUCP are -22.55, -23.10 and -23.79 kJ·mol^-1 at 303, 313, and 323 K, respectively. The values of △H^0 and △S^0 are -3.74 kJ· mol^-1 and 61.99 J·mol^-1, respectively. The adsorption process is spontaneous and exothermic.展开更多
The study on the evaporation kinetics of zinc and lead in the pellets made of ZnPbbearing dust mixed with carbon ,in nitrogen atmosphere at the temperature range between 1 100 and 1 300 , shows that the reduction te...The study on the evaporation kinetics of zinc and lead in the pellets made of ZnPbbearing dust mixed with carbon ,in nitrogen atmosphere at the temperature range between 1 100 and 1 300 , shows that the reduction temperature has a significant effect on the evaporation rates of zinc and lead and that both the particle size of coal powder and the extra carbon content have no effect on the evaporation rates . The obtained activation energies for the evaporation of zinc and lead are 7942 kJ/mol and 8874kJ/mol respectively. The evaporation rate of zinc is controlled by the reaction between zinc oxide and CO while that of lead is controlled by lead volatilization and the diffusion of gaseous lead through gas boundary layer covering the surface of liquid lead.展开更多
A novel technique for the quick measurement moisture content of coal powder by microwave was studied. The effects of the various moisture contents on the measurement results were also discussed. The experimental resul...A novel technique for the quick measurement moisture content of coal powder by microwave was studied. The effects of the various moisture contents on the measurement results were also discussed. The experimental results show that the standard deviation is less than 0.36% when the moisture content of coal powder is 0.74%-16.90% and the standard deviation is less than 0.16% when the moisture content is 0.31%-1.49%. The experimental results indicate that a process of quick measurement moisture content of coal powder by microwave is practical.展开更多
Seven Shenfu coal powders different in particle size obtained by sieving and ball milling were used to probe their adsorption properties to phenol from water. The results show that the kinetics of phenol on coal powde...Seven Shenfu coal powders different in particle size obtained by sieving and ball milling were used to probe their adsorption properties to phenol from water. The results show that the kinetics of phenol on coal powders follow the second-order adsorption kinetic model well. Adsorption processes are governed by film diffusion and the kinetic parameters and the effective diffusion coefficients were calculated through plotting. Adsorption capacities to phenol increase exponentially with decreasing of diameter of coal powders. The phenol adsorption equilibrium for coal powder with d50 of 9.30 μm can be described in terms of Freundlich isotherm, while for ultrafine coal powders with d50 of 4.28 and 4.82 μm fit Langmuir isotherm well.展开更多
The Al2O3 -SiC composite powders were prepared in argon atmosphere rising coal gangue and carbonaceous materials （ carbon black, active carbon and antbravite） as starting materials by carbothermal reduction. Effects...The Al2O3 -SiC composite powders were prepared in argon atmosphere rising coal gangue and carbonaceous materials （ carbon black, active carbon and antbravite） as starting materials by carbothermal reduction. Effects of excessive carbon addition, carbon types. temperature, soaking time. shaping pressure, types and amount of additives on phase composition and micro-structure of the Al2O3 - SiC composite powders were investigated. The re.suits indicate that： temperature, soaking time and chloride additi＇ve have significant influence on the synthesized Al2O3 -SiC composite powders. Based on the results, the optimized Al2O3 -SiC composite powders , Al2O3 58 mass% and SiC 42 mass%, with particle size d50 ≤5μm were prepared using coal gangue and carbon black as starting materials after 3 h firing at 1550 ℃. and proper additive addition could reduce the temperattlre by 50 ℃.展开更多
The powdered coal ash (PCA) was classified, then the ash particle (- 45μm) was modified by a surface active agent and obtained modified powder coal ash (MPCA). The character of the MPC was investigated, when it was u...The powdered coal ash (PCA) was classified, then the ash particle (- 45μm) was modified by a surface active agent and obtained modified powder coal ash (MPCA). The character of the MPC was investigated, when it was used as a new type reinforced filler of rubber.The results show that MPCA can replace or party replace carbon black or silica as reinforced fillers of rubbers.展开更多
Coal gangue(CG)is an environmental waste that faces an urgent demand for disposal in China.The utilization of CG in construction materials has broad application prospects and gained increasing interest.However,the poo...Coal gangue(CG)is an environmental waste that faces an urgent demand for disposal in China.The utilization of CG in construction materials has broad application prospects and gained increasing interest.However,the poor compatibility of polycarboxylate superplasticizer(PCE)with CG powder hinders its efficiency in a wide range of applications.Here,this paper attempts to improve the compatibility of PCE with CG powder in cement paste based on the regulation of aggregation and the adsorption behavior of PCE.Dynamic light scattering(DLS)and fluorescence spectroscopy tests were carried out to understand the improved mechanism.The results indicated that the addition of CG powder increases the ionic strengths of the cement liquid phase,which makes PCE tend to aggregate at a lower concentration compared with no CG powder introduction.Adding(CH_(3)COO)_(2)Cu is beneficial for enhancing the workability of cement paste by reducing PCE aggregation while maintaining the compressive strength of cement specimens.Therefore,(CH_(3)COO)_(2)Cu extra addition can be regarded as an effective and sustainable way to improve the workability of cement paste with CG powder.展开更多
The COREX process is a unique industrialized smelting reduction technology for iron-making presently in the world. One of its striking characteristics is its ability to directly utilize lump coal as its main fuel. The...The COREX process is a unique industrialized smelting reduction technology for iron-making presently in the world. One of its striking characteristics is its ability to directly utilize lump coal as its main fuel. Therefore, the COREX process uses little,or no coke at all. The requirements on lump coal for the COREX process were given in this paper. In order to reduce the coke consumption and give play to the advantages of directly using lump coal ,the appropriate ratio of coke to lump coal needs to be determined. This paper also summerized several advanced methods of using powdered coal generated by the transporting, loading and unloading of lump coal. In order to solve the lack of coal types for COREX and observe the cracking and devolatilization action of lump coal in the melter-gasifier, an experimental device and a new method were proposed to test the cracking and devolatilization characteristics of lump coal. By means of the new method, the devolatilization and cracking behaviors of lump coal can be investigated, which is helpful to the selection of lump coal for the COREX process.展开更多
基金Supported by the National Science Foundation for Post Doctoral Scientists of China （20070411124）, Scientific and Technological Key Project of Shaanxi Province （2006k07-G19）, and Industrialization Project of Shaanxi Provincial Department of Education （06JC 11）.
文摘The adsorption of methyl orange onto ultrafine coal powder （UCP） and modified ultrafine coal powder （MUCP） from aqueous solutions were studied, in which the influence of contact time, dosage, temperature, pH, and methyl orange concentration in the solution were investigated. The adsorption kinetics of methyl orange by UCP and MUCP can be described by the Lagergren first-order and pseudo second-order kinetic models, respectively. The adsorption isotherms of methyl orange onto MUCP at 303, 313 and 323 K follow the Freundlich and Langmuir isotherm equation. Values of △G^0 for methyl orange adsorption onto MUCP are -22.55, -23.10 and -23.79 kJ·mol^-1 at 303, 313, and 323 K, respectively. The values of △H^0 and △S^0 are -3.74 kJ· mol^-1 and 61.99 J·mol^-1, respectively. The adsorption process is spontaneous and exothermic.
文摘The study on the evaporation kinetics of zinc and lead in the pellets made of ZnPbbearing dust mixed with carbon ,in nitrogen atmosphere at the temperature range between 1 100 and 1 300 , shows that the reduction temperature has a significant effect on the evaporation rates of zinc and lead and that both the particle size of coal powder and the extra carbon content have no effect on the evaporation rates . The obtained activation energies for the evaporation of zinc and lead are 7942 kJ/mol and 8874kJ/mol respectively. The evaporation rate of zinc is controlled by the reaction between zinc oxide and CO while that of lead is controlled by lead volatilization and the diffusion of gaseous lead through gas boundary layer covering the surface of liquid lead.
文摘A novel technique for the quick measurement moisture content of coal powder by microwave was studied. The effects of the various moisture contents on the measurement results were also discussed. The experimental results show that the standard deviation is less than 0.36% when the moisture content of coal powder is 0.74%-16.90% and the standard deviation is less than 0.16% when the moisture content is 0.31%-1.49%. The experimental results indicate that a process of quick measurement moisture content of coal powder by microwave is practical.
文摘Seven Shenfu coal powders different in particle size obtained by sieving and ball milling were used to probe their adsorption properties to phenol from water. The results show that the kinetics of phenol on coal powders follow the second-order adsorption kinetic model well. Adsorption processes are governed by film diffusion and the kinetic parameters and the effective diffusion coefficients were calculated through plotting. Adsorption capacities to phenol increase exponentially with decreasing of diameter of coal powders. The phenol adsorption equilibrium for coal powder with d50 of 9.30 μm can be described in terms of Freundlich isotherm, while for ultrafine coal powders with d50 of 4.28 and 4.82 μm fit Langmuir isotherm well.
文摘The Al2O3 -SiC composite powders were prepared in argon atmosphere rising coal gangue and carbonaceous materials （ carbon black, active carbon and antbravite） as starting materials by carbothermal reduction. Effects of excessive carbon addition, carbon types. temperature, soaking time. shaping pressure, types and amount of additives on phase composition and micro-structure of the Al2O3 - SiC composite powders were investigated. The re.suits indicate that： temperature, soaking time and chloride additi＇ve have significant influence on the synthesized Al2O3 -SiC composite powders. Based on the results, the optimized Al2O3 -SiC composite powders , Al2O3 58 mass% and SiC 42 mass%, with particle size d50 ≤5μm were prepared using coal gangue and carbon black as starting materials after 3 h firing at 1550 ℃. and proper additive addition could reduce the temperattlre by 50 ℃.
文摘The powdered coal ash (PCA) was classified, then the ash particle (- 45μm) was modified by a surface active agent and obtained modified powder coal ash (MPCA). The character of the MPC was investigated, when it was used as a new type reinforced filler of rubber.The results show that MPCA can replace or party replace carbon black or silica as reinforced fillers of rubbers.
基金National Key R&D Program of China,No.2022YFB2602604Qiang Yuan,Systematic Project of Guangxi Key Laboratory of Disaster Prevention and Engineering Safety,No.2022ZDK027,Yi Tian.
文摘Coal gangue(CG)is an environmental waste that faces an urgent demand for disposal in China.The utilization of CG in construction materials has broad application prospects and gained increasing interest.However,the poor compatibility of polycarboxylate superplasticizer(PCE)with CG powder hinders its efficiency in a wide range of applications.Here,this paper attempts to improve the compatibility of PCE with CG powder in cement paste based on the regulation of aggregation and the adsorption behavior of PCE.Dynamic light scattering(DLS)and fluorescence spectroscopy tests were carried out to understand the improved mechanism.The results indicated that the addition of CG powder increases the ionic strengths of the cement liquid phase,which makes PCE tend to aggregate at a lower concentration compared with no CG powder introduction.Adding(CH_(3)COO)_(2)Cu is beneficial for enhancing the workability of cement paste by reducing PCE aggregation while maintaining the compressive strength of cement specimens.Therefore,(CH_(3)COO)_(2)Cu extra addition can be regarded as an effective and sustainable way to improve the workability of cement paste with CG powder.
文摘The COREX process is a unique industrialized smelting reduction technology for iron-making presently in the world. One of its striking characteristics is its ability to directly utilize lump coal as its main fuel. Therefore, the COREX process uses little,or no coke at all. The requirements on lump coal for the COREX process were given in this paper. In order to reduce the coke consumption and give play to the advantages of directly using lump coal ,the appropriate ratio of coke to lump coal needs to be determined. This paper also summerized several advanced methods of using powdered coal generated by the transporting, loading and unloading of lump coal. In order to solve the lack of coal types for COREX and observe the cracking and devolatilization action of lump coal in the melter-gasifier, an experimental device and a new method were proposed to test the cracking and devolatilization characteristics of lump coal. By means of the new method, the devolatilization and cracking behaviors of lump coal can be investigated, which is helpful to the selection of lump coal for the COREX process.
