The aim of this study was to determine the quality of rebar produced from recycled scrap metal collected throughout the country,and imported rebar sold in the Republic of Guinea.To do this,the samples were subjected t...The aim of this study was to determine the quality of rebar produced from recycled scrap metal collected throughout the country,and imported rebar sold in the Republic of Guinea.To do this,the samples were subjected to various mechanical tests involving traction,bending and microscopic analysis.In the Lambanyi and Casse Sonfonia samples,all the tensile strength values for diameters 12,14 and 16 were above 550 MPa.Conversely,the iron samples from Baillobaye and the 10 mm diameters of the samples from Casse Sonfonio and Lambanyi have less appreciable values.The limits of elasticity were determined.The various values found vary more or less from the conventional yield strength of the NF A35-016 reference supplied by CBITEC,which is 500 MPa.Microscopic analysis gives us an insight into the internal structure of the iron samples used.This study may provide the company and the vendors with an alternative for their improvements.展开更多
Soybean soapstock(SS) is one of the main solid wastes produced in the refinery of edible oil processing. In this study, the co-pyrolysis of SS with iron slag(IS) and aluminum scrap(AS) was carried out in a tubular fur...Soybean soapstock(SS) is one of the main solid wastes produced in the refinery of edible oil processing. In this study, the co-pyrolysis of SS with iron slag(IS) and aluminum scrap(AS) was carried out in a tubular furnace. The gas, liquid and solid products were characterized and the char yield decreased with increasing IS/AS ratio. IS and AS can improve the gas yield, and when the ratio of SS/IS was 1:0.25, the total pyrolysis gas and hydrogen contents were significantly increased. The content of oxygen compounds in pyrolysis oil decreased during co-pyrolysis, while AS promoted the content of polycyclic aromatic hydrocarbons in pyrolysis oil. The co-pyrolysis reaction can be divided into four stages, the mass loss rate reaches the maximum at the third stage(390–575 ℃). The molar ratio of H/C was lower for pyrolysis,indicating good stability of pyrolysis char owing to the high degree of carbonization and aromaticity.The possible co-pyrolysis reaction mechanism was explored.展开更多
The abnormal corrosion of hot iron ladles was investigated.The performance,the composition and the structure of bricks for hot iron ladles were analyzed.The results show that(1)compared with the alumina-silicon carbid...The abnormal corrosion of hot iron ladles was investigated.The performance,the composition and the structure of bricks for hot iron ladles were analyzed.The results show that(1)compared with the alumina-silicon carbide-carbon bricks for the ladle bottom,those for the ladle wall have more pyrophyllite and the Al2O3 content of 36.32 mass%;their bulk density,apparent porosity and cold compressive strength are lower than the requirement of industry standard;they have poor anti-oxidation performance and are oxidized to form a porous layer during service,which loosens the brick lining structure thus leading to fracture,local wear and structural damage of bricks;(2)without preheating,steel scraps are not completely melted,resulting in slag or steel attachment at the mouth or the bottom of ladles thus increasing damage of ladles;(3)and the residual bricks react with the attached slag to form low melting point phases affecting their hot properties.The refractories for the lining of hot iron ladles must be improved in combination with process changes,not entirely by raw materials replacement to reduce costs.展开更多
文摘The aim of this study was to determine the quality of rebar produced from recycled scrap metal collected throughout the country,and imported rebar sold in the Republic of Guinea.To do this,the samples were subjected to various mechanical tests involving traction,bending and microscopic analysis.In the Lambanyi and Casse Sonfonia samples,all the tensile strength values for diameters 12,14 and 16 were above 550 MPa.Conversely,the iron samples from Baillobaye and the 10 mm diameters of the samples from Casse Sonfonio and Lambanyi have less appreciable values.The limits of elasticity were determined.The various values found vary more or less from the conventional yield strength of the NF A35-016 reference supplied by CBITEC,which is 500 MPa.Microscopic analysis gives us an insight into the internal structure of the iron samples used.This study may provide the company and the vendors with an alternative for their improvements.
基金supported by China-Central and Eastern Europe Universities Joint Education Project(2021128).
文摘Soybean soapstock(SS) is one of the main solid wastes produced in the refinery of edible oil processing. In this study, the co-pyrolysis of SS with iron slag(IS) and aluminum scrap(AS) was carried out in a tubular furnace. The gas, liquid and solid products were characterized and the char yield decreased with increasing IS/AS ratio. IS and AS can improve the gas yield, and when the ratio of SS/IS was 1:0.25, the total pyrolysis gas and hydrogen contents were significantly increased. The content of oxygen compounds in pyrolysis oil decreased during co-pyrolysis, while AS promoted the content of polycyclic aromatic hydrocarbons in pyrolysis oil. The co-pyrolysis reaction can be divided into four stages, the mass loss rate reaches the maximum at the third stage(390–575 ℃). The molar ratio of H/C was lower for pyrolysis,indicating good stability of pyrolysis char owing to the high degree of carbonization and aromaticity.The possible co-pyrolysis reaction mechanism was explored.
文摘The abnormal corrosion of hot iron ladles was investigated.The performance,the composition and the structure of bricks for hot iron ladles were analyzed.The results show that(1)compared with the alumina-silicon carbide-carbon bricks for the ladle bottom,those for the ladle wall have more pyrophyllite and the Al2O3 content of 36.32 mass%;their bulk density,apparent porosity and cold compressive strength are lower than the requirement of industry standard;they have poor anti-oxidation performance and are oxidized to form a porous layer during service,which loosens the brick lining structure thus leading to fracture,local wear and structural damage of bricks;(2)without preheating,steel scraps are not completely melted,resulting in slag or steel attachment at the mouth or the bottom of ladles thus increasing damage of ladles;(3)and the residual bricks react with the attached slag to form low melting point phases affecting their hot properties.The refractories for the lining of hot iron ladles must be improved in combination with process changes,not entirely by raw materials replacement to reduce costs.
