2014 Vol. 5 No. 3
Abstract：
This paper puts forward the new technology of making asymmetric ceramic composite film tube. First, materials including SiC and Al2O3 are fired into the porous ceramic substrate after static pressure molding. The asymmetric ceramic tube membrane is made by high temperature sintering after reaching the required film thickness by leaching pulp and drying for many times. The high temperature flue gas composite membrane filter can be applied to remove dust and gas in metallurgical processing. SEM and EDS are used to characterize the porous ceramics matrix and microporous composite membrane. The results show that they have good pore structure and physical properties. A set of cold model test devices for measuring dust filtration efficiency of asymmetric ceramic composite membrane is designed and reasonable parameters are determined through experiments.
This paper puts forward the new technology of making asymmetric ceramic composite film tube. First, materials including SiC and Al2O3 are fired into the porous ceramic substrate after static pressure molding. The asymmetric ceramic tube membrane is made by high temperature sintering after reaching the required film thickness by leaching pulp and drying for many times. The high temperature flue gas composite membrane filter can be applied to remove dust and gas in metallurgical processing. SEM and EDS are used to characterize the porous ceramics matrix and microporous composite membrane. The results show that they have good pore structure and physical properties. A set of cold model test devices for measuring dust filtration efficiency of asymmetric ceramic composite membrane is designed and reasonable parameters are determined through experiments.
2014, 5(3): 9-15.
DOI: 10.13264/j.cnki.ysjskx.2014.03.002
Abstract：
A new technology of reduction precipitation combined with crystal seed aeration is proposed for completely removing Cr6+and Mn2+ from electrolytic manganese wastewater by studying the optimum treatment conditions.In the first step, Cr6+was removed by chemical precipitation by transforming into Cr3+using Na2SO3 as reductant.Then Mn2+ is removed by aeration using MnO2 as crystal seed.The results are as follows: Cr6+can be transformed into Cr3+completely with Na2SO3 dosage of 0.5 g/L, reduction pH value of 4, reduction time of 6 min.Precipitation of Cr3+is the most complete when pH value is 8 and the effluent concentration of total chromium is less than 0.5 mg/L from 100 mg/L.After chromium removal, the effluent concentration of Mn2+ is less than 0.4 mg/L from 1 000 mg/L when MnO2 dosage is 25 g/L, wastewater pH value is 9 and aeration time is 10 min which meets the first grade national sewage effluent discharge standard (GB8978-1996).
A new technology of reduction precipitation combined with crystal seed aeration is proposed for completely removing Cr6+and Mn2+ from electrolytic manganese wastewater by studying the optimum treatment conditions.In the first step, Cr6+was removed by chemical precipitation by transforming into Cr3+using Na2SO3 as reductant.Then Mn2+ is removed by aeration using MnO2 as crystal seed.The results are as follows: Cr6+can be transformed into Cr3+completely with Na2SO3 dosage of 0.5 g/L, reduction pH value of 4, reduction time of 6 min.Precipitation of Cr3+is the most complete when pH value is 8 and the effluent concentration of total chromium is less than 0.5 mg/L from 100 mg/L.After chromium removal, the effluent concentration of Mn2+ is less than 0.4 mg/L from 1 000 mg/L when MnO2 dosage is 25 g/L, wastewater pH value is 9 and aeration time is 10 min which meets the first grade national sewage effluent discharge standard (GB8978-1996).
2014, 5(3): 16-20.
DOI: 10.13264/j.cnki.ysjskx.2014.03.003
Abstract：
Graphene/FePO4·2H2O composite precursors are prepared by homogeneous precipitation method with Fe (NO3)3·9H2O, NaH2PO4·2H2O and H3PO4, added in graphene oxide (GO).Results show that GO can change the morphology of FePO4·2H2O powders from flocculent to round.Then the round powders are concentrated by filtration, and raw materials are dropped in the products to make the powders re-grow.The final powders are spherical with homogeneous particle size (D50=4.220 μm, the tap density is 1.31 g/m3).The analysis of XRD, FT-IR and Raman data shows that GO is mainly reduced to grapheme which has great value for the preparation of graphene/FePO4·2H2O composite precursor.
Graphene/FePO4·2H2O composite precursors are prepared by homogeneous precipitation method with Fe (NO3)3·9H2O, NaH2PO4·2H2O and H3PO4, added in graphene oxide (GO).Results show that GO can change the morphology of FePO4·2H2O powders from flocculent to round.Then the round powders are concentrated by filtration, and raw materials are dropped in the products to make the powders re-grow.The final powders are spherical with homogeneous particle size (D50=4.220 μm, the tap density is 1.31 g/m3).The analysis of XRD, FT-IR and Raman data shows that GO is mainly reduced to grapheme which has great value for the preparation of graphene/FePO4·2H2O composite precursor.
2014, 5(3): 21-27.
DOI: 10.13264/j.cnki.ysjskx.2014.03.004
Abstract：
Through the different pyrolysis time tests in 200 kg coke oven of lump coal mainly used in melter gasifier, namely A coal and B coal, the size distribution and strength change of the two coals after coking was compared. Results showed that the pulverization of B coal in coke oven was severe, which size degradation rate (DR) was always increasing with the coking time prolonging. On the contrary, the DR of A coal was decreasing once reached the maximum value. The mineral microstructure of semi coke formed by the two coal pyrolysis in coke oven was also compared. It was found that semi coke formed by A coal was mainly mosaic and isotropy stucture, and the other semi coke formed by B coal was mainly fusain and isotropy structure. There was still some coal residue in both semi cokes. Through the mineral microstructure analysis of different particle size of carbon-containing materials in tuyere samples taken out from melter gasifier, it was found that the particles less than 6.3 mm in hearth were caused by the semi coke pulverization. Moreover, the pulverization of semi coke was mainly form B coal.
Through the different pyrolysis time tests in 200 kg coke oven of lump coal mainly used in melter gasifier, namely A coal and B coal, the size distribution and strength change of the two coals after coking was compared. Results showed that the pulverization of B coal in coke oven was severe, which size degradation rate (DR) was always increasing with the coking time prolonging. On the contrary, the DR of A coal was decreasing once reached the maximum value. The mineral microstructure of semi coke formed by the two coal pyrolysis in coke oven was also compared. It was found that semi coke formed by A coal was mainly mosaic and isotropy stucture, and the other semi coke formed by B coal was mainly fusain and isotropy structure. There was still some coal residue in both semi cokes. Through the mineral microstructure analysis of different particle size of carbon-containing materials in tuyere samples taken out from melter gasifier, it was found that the particles less than 6.3 mm in hearth were caused by the semi coke pulverization. Moreover, the pulverization of semi coke was mainly form B coal.
2014, 5(3): 28-31, 75.
DOI: 10.13264/j.cnki.ysjskx.2014.03.005
Abstract：
Using the YCl3and oxalic acid as raw materials, effect of microwave on morphology of synthesis Y2O3 precursor in the liquid phase are investigated. The effects of mole ratio of H2C2O4 to YCl3, initial concentrations of YCl3, reaction time and reaction temperature on the morphology and the dispersion of precursor were investigated. By using means of techniques such as scanning electron microscope (SEM), X-Ray Diffraction (XRD) and TG-DTA to precursors and thermal decomposition products are characterized. The results showed that the large particle size and sand shape precursor with the average particle size of about 40 μm was produced under the conditions: mole ratio of H2C2O4 to YCl3 is 2:1, initial concentration of YCl3 is 0.5 mol/L, reaction temperature is 40 ℃ and 3 h reaction time.
Using the YCl3and oxalic acid as raw materials, effect of microwave on morphology of synthesis Y2O3 precursor in the liquid phase are investigated. The effects of mole ratio of H2C2O4 to YCl3, initial concentrations of YCl3, reaction time and reaction temperature on the morphology and the dispersion of precursor were investigated. By using means of techniques such as scanning electron microscope (SEM), X-Ray Diffraction (XRD) and TG-DTA to precursors and thermal decomposition products are characterized. The results showed that the large particle size and sand shape precursor with the average particle size of about 40 μm was produced under the conditions: mole ratio of H2C2O4 to YCl3 is 2:1, initial concentration of YCl3 is 0.5 mol/L, reaction temperature is 40 ℃ and 3 h reaction time.
2014, 5(3): 32-37.
DOI: 10.13264/j.cnki.ysjskx.2014.03.006
Abstract：
The test techniques of OM、XRD and TG/DTA were used to study the microstructure, cutting properties and dezincification corrosion resistance systematically of the lead-free silicon brass with different phase composition, namely (α+β), β and (β+γ). Results showed the cutting force of silicon brass with the matrix of (α+β) phases was low enough, however it's chip morphology was dissatisfactory, while the average thickness of dezincification layer was 438.12μm, which was the biggest; while the silicon brass with the matrix of (β+γ) phases had the worst chip morphology and the highest Brinell hardness, namely 273.7HB, which meanses the highest cutting force, increasing tool wear and reducing the tool life; the silicon brass with just single phase β had higher cutting force, but the smaller roll chips, which was the best chip morphology, meanwhile it performed the minimum average dezincification layer, Specifically 262.94 μm, during the dezincification corrosion resistance test. therefore, the silicon brass with just single phase β had the best comprehensive properties, brass with the matrix of (β+γ) phases is not suitable for cutting brass, while the cutting performance and corrosion resistance of the brass with (α+β) phase are yet to be improved.
The test techniques of OM、XRD and TG/DTA were used to study the microstructure, cutting properties and dezincification corrosion resistance systematically of the lead-free silicon brass with different phase composition, namely (α+β), β and (β+γ). Results showed the cutting force of silicon brass with the matrix of (α+β) phases was low enough, however it's chip morphology was dissatisfactory, while the average thickness of dezincification layer was 438.12μm, which was the biggest; while the silicon brass with the matrix of (β+γ) phases had the worst chip morphology and the highest Brinell hardness, namely 273.7HB, which meanses the highest cutting force, increasing tool wear and reducing the tool life; the silicon brass with just single phase β had higher cutting force, but the smaller roll chips, which was the best chip morphology, meanwhile it performed the minimum average dezincification layer, Specifically 262.94 μm, during the dezincification corrosion resistance test. therefore, the silicon brass with just single phase β had the best comprehensive properties, brass with the matrix of (β+γ) phases is not suitable for cutting brass, while the cutting performance and corrosion resistance of the brass with (α+β) phase are yet to be improved.
2014, 5(3): 38-43.
DOI: 10.13264/j.cnki.ysjskx.2014.03.007
Abstract：
Finite element simulation is performed on the pre-rolling, pre-water cooling and rolling processes of the ML08Al wire rod with specification of Φ6.5mm. The pre-rolling temperature of the rolled piece begins at 980 ℃. The simulation results of the temperature and deformation are consistent with the actual production situation. The result shows that the center temperature of rolled pieces is very high and the surface temperature of rolled pieces is low during the whole pre-rolling and rolling processes. Deformation of the rolled pieces mainly occurs in the heart of rolled pieces and diagonal directions. These areas are more likely to achieve the condition of dynamic recrystallization and refine the grain. With the condition of deformation and temperature, the gap of core organization and surface organization can aggravate the mixed grain structure. Improving the pre-cooling intensity can inhibit the grain growth and increase the organization uniformity of the product.
Finite element simulation is performed on the pre-rolling, pre-water cooling and rolling processes of the ML08Al wire rod with specification of Φ6.5mm. The pre-rolling temperature of the rolled piece begins at 980 ℃. The simulation results of the temperature and deformation are consistent with the actual production situation. The result shows that the center temperature of rolled pieces is very high and the surface temperature of rolled pieces is low during the whole pre-rolling and rolling processes. Deformation of the rolled pieces mainly occurs in the heart of rolled pieces and diagonal directions. These areas are more likely to achieve the condition of dynamic recrystallization and refine the grain. With the condition of deformation and temperature, the gap of core organization and surface organization can aggravate the mixed grain structure. Improving the pre-cooling intensity can inhibit the grain growth and increase the organization uniformity of the product.
2014, 5(3): 44-49.
DOI: 10.13264/j.cnki.ysjskx.2014.03.008
Abstract：
In view of shortcomings in current bismuth-molybdenum ores' floating and smelting technologies, such as complex operation in ore-dressing, large consumption of floating reagents and incomplete separation of bismuth and molybdenum, a low-temperature smelting on bismuth-molybdenum ores is proposed so that the crude bismuth is produced after low-temperature smelting, and molybdenum comes into the solution in form of molybdate. Then molybdenum trioxide can be recycled which is produced by hydrothermal method. On the basis of thermodynamic analysis, effects of molten salt composition, salt amount, smelting temperature, reaction composition and excessive multiples of active carbon on the molten salt smelting of bismuth-molybdenum ores are investigated. The optimum conditions is determined as follows: w(NaCl) /w (NaCl+Na2CO3)=20 %, smelting temperature 850 ℃, w(NaCl+Na2CO3) /w(bismuth-molybdenum ores)=2, reaction time 1 h, w(activated carbon) /w(theory)=2. Two comprehensive tests under above-mentioned optimum conditions are conducted to find out that the direct recovery rate of bismuth is 98.12 % and 96.59 %, and the average grade of crude bismuth is 96.62 % and 98.87 %.
In view of shortcomings in current bismuth-molybdenum ores' floating and smelting technologies, such as complex operation in ore-dressing, large consumption of floating reagents and incomplete separation of bismuth and molybdenum, a low-temperature smelting on bismuth-molybdenum ores is proposed so that the crude bismuth is produced after low-temperature smelting, and molybdenum comes into the solution in form of molybdate. Then molybdenum trioxide can be recycled which is produced by hydrothermal method. On the basis of thermodynamic analysis, effects of molten salt composition, salt amount, smelting temperature, reaction composition and excessive multiples of active carbon on the molten salt smelting of bismuth-molybdenum ores are investigated. The optimum conditions is determined as follows: w(NaCl) /w (NaCl+Na2CO3)=20 %, smelting temperature 850 ℃, w(NaCl+Na2CO3) /w(bismuth-molybdenum ores)=2, reaction time 1 h, w(activated carbon) /w(theory)=2. Two comprehensive tests under above-mentioned optimum conditions are conducted to find out that the direct recovery rate of bismuth is 98.12 % and 96.59 %, and the average grade of crude bismuth is 96.62 % and 98.87 %.
2014, 5(3): 50-55.
DOI: 10.13264/j.cnki.ysjskx.2014.03.009
Abstract：
Sodium tungstate and hydrochloric acid are used as raw materials, carbon nanotubes as template, tungsten acid and carbon nanotube composite are prepared respectively by using one-step and two-step method, and then roasted at 600 ℃ for 2 h under oxygen atmosphere. The average particle size of tungsten acid and carbon nanotubes composite prepared one and two step methods are 10 nm and 100 nm respectively. The average particle size of tungsten oxide powders are 250 nm and 2 μm respectively. The specific surface area of tungsten oxide powders is 36.53 m2/g and 13.99 m2/g respectively. The photocatalytic performance of tungsten oxide is studied by the UV-Vis spectrophotometer using 11W fluorescent light as the light source. The degradation rate of tungsten oxide powders can reach 93.8 % and 79.1 %. The physical absorption and photocatalytic activity of tungsten oxide prepared by one-step method is better than that of two-step method because of its smaller particle diameter and higher specific surface area.
Sodium tungstate and hydrochloric acid are used as raw materials, carbon nanotubes as template, tungsten acid and carbon nanotube composite are prepared respectively by using one-step and two-step method, and then roasted at 600 ℃ for 2 h under oxygen atmosphere. The average particle size of tungsten acid and carbon nanotubes composite prepared one and two step methods are 10 nm and 100 nm respectively. The average particle size of tungsten oxide powders are 250 nm and 2 μm respectively. The specific surface area of tungsten oxide powders is 36.53 m2/g and 13.99 m2/g respectively. The photocatalytic performance of tungsten oxide is studied by the UV-Vis spectrophotometer using 11W fluorescent light as the light source. The degradation rate of tungsten oxide powders can reach 93.8 % and 79.1 %. The physical absorption and photocatalytic activity of tungsten oxide prepared by one-step method is better than that of two-step method because of its smaller particle diameter and higher specific surface area.
2014, 5(3): 56-59.
DOI: 10.13264/j.cnki.ysjskx.2014.03.010
Abstract：
The solidified bodies are prepared by adding different content jarosite slag in Portland cement by normal curing at 50 ℃, 100 % humidity and for 56 d. The effects of addition amount of jarosite slag on strength and microstructure of solidification body are studied. The effects of the hydrothermal extreme environments with temperature of 200 ℃and pressure of 1.56 MPa on the structure, morphology and strength of solidified body are studied. The result indicates that after being cured at normal condition, the phase of solidifies body are trabzonite, hydration calcium aluminum silicate and hydration calcium. The structure of solidification body becomes loose, and the content of gypsum increases with the increase of jarosite slag content. After being treated in extreme environments, the phase of solidifies body are mainly calcium aluminum silicate and calcium silicate with increase of crystallization, dehydrating of gypsum, loosening of solidification structure and reduction in its strength, and the maximum addition amount of jarosite is 60 %.
The solidified bodies are prepared by adding different content jarosite slag in Portland cement by normal curing at 50 ℃, 100 % humidity and for 56 d. The effects of addition amount of jarosite slag on strength and microstructure of solidification body are studied. The effects of the hydrothermal extreme environments with temperature of 200 ℃and pressure of 1.56 MPa on the structure, morphology and strength of solidified body are studied. The result indicates that after being cured at normal condition, the phase of solidifies body are trabzonite, hydration calcium aluminum silicate and hydration calcium. The structure of solidification body becomes loose, and the content of gypsum increases with the increase of jarosite slag content. After being treated in extreme environments, the phase of solidifies body are mainly calcium aluminum silicate and calcium silicate with increase of crystallization, dehydrating of gypsum, loosening of solidification structure and reduction in its strength, and the maximum addition amount of jarosite is 60 %.
2014, 5(3): 60-64.
DOI: 10.13264/j.cnki.ysjskx.2014.03.011
Abstract：
This paper compares the different ball milling efficiencies and methods by using different milling mediums (Self-designed Heptahedron Milling and Ball-milling) during WC-10 %Co's wet grinding preparation process. The analysis of sintered alloy properties shows the effect of different ball milling mediums on alloy properties. The results indicate that: The efficiency of Heptahedron Milling Medium is higher than Ball-milling by bringing more powder activity and oxygen-adding tendency during the mixture storage process. It therefore causes relatively lower cobalt and magnetism contents. Adding 0.2 % paraffin can prevent powder oxidation. Heptahedron milling medium is suitable for the mixture preparation with raw materials' Fisher particle size larger than 5.0 μ m, while ball milling medium is suitable for raw materials' Fisher particle size 0.8~5.0 μ m.
This paper compares the different ball milling efficiencies and methods by using different milling mediums (Self-designed Heptahedron Milling and Ball-milling) during WC-10 %Co's wet grinding preparation process. The analysis of sintered alloy properties shows the effect of different ball milling mediums on alloy properties. The results indicate that: The efficiency of Heptahedron Milling Medium is higher than Ball-milling by bringing more powder activity and oxygen-adding tendency during the mixture storage process. It therefore causes relatively lower cobalt and magnetism contents. Adding 0.2 % paraffin can prevent powder oxidation. Heptahedron milling medium is suitable for the mixture preparation with raw materials' Fisher particle size larger than 5.0 μ m, while ball milling medium is suitable for raw materials' Fisher particle size 0.8~5.0 μ m.
2014, 5(3): 65-69.
DOI: 10.13264/j.cnki.ysjskx.2014.03.012
Abstract：
The research status of tungsten extraction technique is analyzed from the perspective of Chinese patents. The patents published before 2014/03/08 with IPC C22B34/36 in CNABS are searched and studied to analyze the application type, development trend of annual application, regional distribution of applicants and main patent applicants. The patents applied and patented between the year of 2010 and 2013 are introduced to provide reference to the related enterprises and researchers.
The research status of tungsten extraction technique is analyzed from the perspective of Chinese patents. The patents published before 2014/03/08 with IPC C22B34/36 in CNABS are searched and studied to analyze the application type, development trend of annual application, regional distribution of applicants and main patent applicants. The patents applied and patented between the year of 2010 and 2013 are introduced to provide reference to the related enterprises and researchers.
2014, 5(3): 70-75.
DOI: 10.13264/j.cnki.ysjskx.2014.03.013
Abstract：
Power plant fly ash can be maked with better adsorption capacity of coal fly ash carbon, To study the effect of different pH, dosage, time, temperature, solution concentration, adsorption methods on Cr removal by coal fly ash carbon.The results showed that the adsorption reaction is endothermic process; With the acidity of pH=2, the maximum adsorption capacity of Cr (Ⅵ) was 4.67 mg/g at 25 ℃ constant temperature, with the ratio of Cr and coal fly ash carbon is 250, and the contacing time over 120 min; Using NaOH solution to desorb Cr from the Cr-saturating coal fly ash carbon, the concentration of 0.05 mol/L is the most effective, desorb rate is 129%. Wastewater produced by discards printed circuit boards wet process, which Cr (Ⅵ) concentration is 0.62mg/L, in the above condition, the removal rate of Cr (Ⅵ) is 95.16%; If under the condition of natural pH, Cr (Ⅵ) removal rate can reach 91.94%, also meet the integrated wastewater discharge standard. The treatment of metal containing wastewater by coal fly ash carbon has a promising future.
Power plant fly ash can be maked with better adsorption capacity of coal fly ash carbon, To study the effect of different pH, dosage, time, temperature, solution concentration, adsorption methods on Cr removal by coal fly ash carbon.The results showed that the adsorption reaction is endothermic process; With the acidity of pH=2, the maximum adsorption capacity of Cr (Ⅵ) was 4.67 mg/g at 25 ℃ constant temperature, with the ratio of Cr and coal fly ash carbon is 250, and the contacing time over 120 min; Using NaOH solution to desorb Cr from the Cr-saturating coal fly ash carbon, the concentration of 0.05 mol/L is the most effective, desorb rate is 129%. Wastewater produced by discards printed circuit boards wet process, which Cr (Ⅵ) concentration is 0.62mg/L, in the above condition, the removal rate of Cr (Ⅵ) is 95.16%; If under the condition of natural pH, Cr (Ⅵ) removal rate can reach 91.94%, also meet the integrated wastewater discharge standard. The treatment of metal containing wastewater by coal fly ash carbon has a promising future.
2014, 5(3): 76-80.
DOI: 10.13264/j.cnki.ysjskx.2014.03.014
Abstract：
It is always a focus to improve the selectivity of collector and strengthen the efficiency of depressor in the study of scheelite flotation. The type of scheelite collector and adjustment, mechanism and research status are analyzed and reported, and it is put forward that the high selective collector and pertinence of inhibitory is an urgent problem needing to be solved in the scheelite flotation. It has become the development trend of white tungsten flotation reagents that using new and high technology and combining with the theoretical research to develop efficient, economic and environmental protective flotation reagents.
It is always a focus to improve the selectivity of collector and strengthen the efficiency of depressor in the study of scheelite flotation. The type of scheelite collector and adjustment, mechanism and research status are analyzed and reported, and it is put forward that the high selective collector and pertinence of inhibitory is an urgent problem needing to be solved in the scheelite flotation. It has become the development trend of white tungsten flotation reagents that using new and high technology and combining with the theoretical research to develop efficient, economic and environmental protective flotation reagents.
2014, 5(3): 81-85.
DOI: 10.13264/j.cnki.ysjskx.2014.03.015
Abstract：
Potential regulation-sulfide precipitation are used to treat zinc-containing mine acid drainage with the concentration of 100mg/L deeply. When 10 % CaO is selected as a neutralizing agent to remove iron, (the amount of 10 % CaO 7.5~14 ml/L, precipitation time of iron 30 min), the removal rate of iron could reach above 80 %. Vulcanization is performed on the de-ironed solution to precipitate zinc using NaHS as the vulcanizing agent, (with the sulfide precipitation zinc pH value of 3.4, the dosing quantity of PAM flocculant of 1 mL/L, and ORP of at 6~76 mV), the removal rate of zinc ions in acid drainage can be over 96.85 %.
Potential regulation-sulfide precipitation are used to treat zinc-containing mine acid drainage with the concentration of 100mg/L deeply. When 10 % CaO is selected as a neutralizing agent to remove iron, (the amount of 10 % CaO 7.5~14 ml/L, precipitation time of iron 30 min), the removal rate of iron could reach above 80 %. Vulcanization is performed on the de-ironed solution to precipitate zinc using NaHS as the vulcanizing agent, (with the sulfide precipitation zinc pH value of 3.4, the dosing quantity of PAM flocculant of 1 mL/L, and ORP of at 6~76 mV), the removal rate of zinc ions in acid drainage can be over 96.85 %.
2014, 5(3): 86-90.
DOI: 10.13264/j.cnki.ysjskx.2014.03.016
Abstract：
To better understand mine blasting seismic wave attenuation rule, on the basis of in determining the mine blasting vibration signal best wavelet base and threshold function, make the original signal and noise signal measured on SaDaoFu linear matching for analysis. The results show that: The mine blasting vibration signal for the best wavelet base is sym7 function, the denoising effect for the best is rigrsure threshold function. After denoising it is more accurate to know the mine rock mass strength properties from blasting vibration signal attenuation coefficient k, a value compared the original data, Related research can provide theoretical basis for the mine blasting safety design.
To better understand mine blasting seismic wave attenuation rule, on the basis of in determining the mine blasting vibration signal best wavelet base and threshold function, make the original signal and noise signal measured on SaDaoFu linear matching for analysis. The results show that: The mine blasting vibration signal for the best wavelet base is sym7 function, the denoising effect for the best is rigrsure threshold function. After denoising it is more accurate to know the mine rock mass strength properties from blasting vibration signal attenuation coefficient k, a value compared the original data, Related research can provide theoretical basis for the mine blasting safety design.
2014, 5(3): 91-95.
DOI: 10.13264/j.cnki.ysjskx.2014.03.017
Abstract：
Cracks of different widths and depths are observed in the cemented backfill roof in Wushan Copper Mine resulted from gravity stress and blasting vibration. The stability of backfill is affected when the cracks reach a point. This paper uses ANSYS software and GeoStudio2007 SIGMA/W module to simulate the stress-strain in the roof fissure filling body. The stability classification of filling body's base plate is studied based on ANSYS and GeoStudio coupling. Corresponding suggestions are put forward according to different stability statuses.
Cracks of different widths and depths are observed in the cemented backfill roof in Wushan Copper Mine resulted from gravity stress and blasting vibration. The stability of backfill is affected when the cracks reach a point. This paper uses ANSYS software and GeoStudio2007 SIGMA/W module to simulate the stress-strain in the roof fissure filling body. The stability classification of filling body's base plate is studied based on ANSYS and GeoStudio coupling. Corresponding suggestions are put forward according to different stability statuses.
2014, 5(3): 96-101.
DOI: 10.13264/j.cnki.ysjskx.2014.03.018
Abstract：
This paper is based on the mountain silt-sand mixed soft soil foundation of Jing-mu highway project. Through technical comparison and economic analysis of the treatment programs of the soft soil foundation about the Pine pile, the CFG pile (Cement Fly-ash Gravel Pile) and the Cement Deep Mixing pile are made so as to select the best treatment program. The study shows that the cost of the Pine pile is the highest among the three treatment programs of the soft soil foundation which is limited by the processing depth and the bearing capacity to be chosen as the best option. Under the same conditions, the cost of the CFG pile is so much expensive as to 1.4 times that of the cement deep mixing pile. Finally, cement deep mixing pile is chosen to handle the silt-sand mixed soft soil foundation in this project.
This paper is based on the mountain silt-sand mixed soft soil foundation of Jing-mu highway project. Through technical comparison and economic analysis of the treatment programs of the soft soil foundation about the Pine pile, the CFG pile (Cement Fly-ash Gravel Pile) and the Cement Deep Mixing pile are made so as to select the best treatment program. The study shows that the cost of the Pine pile is the highest among the three treatment programs of the soft soil foundation which is limited by the processing depth and the bearing capacity to be chosen as the best option. Under the same conditions, the cost of the CFG pile is so much expensive as to 1.4 times that of the cement deep mixing pile. Finally, cement deep mixing pile is chosen to handle the silt-sand mixed soft soil foundation in this project.
Abstract：
This paper briefly describes the production and separation technology of ion-adsorption rare earth, materials and products, the possibility and distribution of occupational hazard factors exist during the production processes, occupational disease prevention facilities, prevention articles, health auxiliary clinics and occupational health management. Occupational hazards in the workplace were evaluated by determining the critical control points, including soluble material, extraction, precipitation and firing. The concentration and intensity of occupational hazards in the workplace can be controlled during the normal operation without obvious negative effects on workers.
This paper briefly describes the production and separation technology of ion-adsorption rare earth, materials and products, the possibility and distribution of occupational hazard factors exist during the production processes, occupational disease prevention facilities, prevention articles, health auxiliary clinics and occupational health management. Occupational hazards in the workplace were evaluated by determining the critical control points, including soluble material, extraction, precipitation and firing. The concentration and intensity of occupational hazards in the workplace can be controlled during the normal operation without obvious negative effects on workers.
