Water quenching blast furnace slag （WQBFS） is widely produced in the blast furnace iron making process. It is mainly composed of CoO, MgO, A1203, and SiO2 with low contents of other metal elements such as Fe, Mn, Ti...Water quenching blast furnace slag （WQBFS） is widely produced in the blast furnace iron making process. It is mainly composed of CoO, MgO, A1203, and SiO2 with low contents of other metal elements such as Fe, Mn, Ti, K and No. In this study, WQBFS was treated with grinding, hydrochloric acid acidification, filtration, filtrate extraction by alkali liquor and a hydration reaction. Then BFS micropowder （BFSMP）, BFS acidified solid （BFSAS） and BFS acid-alkali precipitate （BFSAP） were obtained, which were characterized by X-ray diffrac- tion, scanning electron microscopy, X-ray fluorescence and Brunauer-Emmet-Teller （BET） specific surface area. The decoloration efficiency for Methyl Orange （MO） was used to evaluate the adsorptive ability of the three absorbents. The effects of adsorptive reaction conditions （pH and temperature of solution, reaction time, sorbent dosage and initial concentration） on MO removal were also investigated in detail. The results indicated that BFSAP performed better in MO removal than the other two absorbents. When the pH value of MO solutions was in the range 3.0-13.0, the degradation efficiency of a solution with initial MO concentration of 25 mg/L reached 99.97% for a reaction time of 25 rain at 25℃. The maximum adsorption capacity of BFSAP for MO was 167 mg/g. Based on optimized experiments, the results conformed with the Langrnuir adsorption isotherm and pseudo-second-order kinetics. Among inorganic anions, SO2- and PO4- had significant inhibitory effects on MO removal in BFSAP treatment due to ion-exchange adsorption.展开更多
A 13% chromium white iron was produced using a stir cast process. Samples of the produced white iron were austenised at 1450°C and then quenched in water to the room temperature. The characterisation tools such a...A 13% chromium white iron was produced using a stir cast process. Samples of the produced white iron were austenised at 1450°C and then quenched in water to the room temperature. The characterisation tools such as X-ray diffractometer, scanning electron microscope, Brinell hardness tester and pin on disc machine were employed in the studies of the phase orientation and morphology, hardness value measurement and investigation of wear behaviour. The results revealed that water quenching the 13% chromium white iron led to the precipitation of fine iron chromides and cementite in the matrix of martensite. Moreover, there is an about 22% to 45% increase in hardness values of the as-cast 13% chromium white iron as the %composition of graphite additions increased from 1.36 to 3.04. However, the impact energy values are sacrificed. The increase in hardness values is attributable to hard intermetallic compounds such as iron chromides and cementite phases in the iron matrix. Also, there is an about 32% - 42% increase in hardness values of the heat treated samples of 13% chromium white iron when compared with those of the as-cast. The increased hardness values are attributable to even distribution of the fine intermetallic compounds in the fine grains of martensitic matrix. The wear rate increased as the sliding moments per unit time increased due to increasing work done by the friction to oppose the rotation of the pin on disc. The water quenched 13% chromium white iron samples have greater wear resistances than the as-cast samples due to their greater hardness values than those of the as-cast samples. The effect of speed increase on decreasing wear resistances is more pronounced on the heat treated samples than on the as-cast samples. Hence, the water quenched 13% chromium white iron is an excellent material in application requiring high wear resistance and low impact energy especially in grinding mill liner plate, bottom or casing used in the concrete pipe production, roller for crushing and pulverising mills.展开更多
基金supported by the National Nature Science Foundation of China(Nos.21277130,51478445,51338010 and 21477118)the Key Program Nature Science Foundation of Hubei Province(No.2014CFA530)+1 种基金Chinese Universities Scientific Fund(CUG)China Postdoctoral Science Foundation under 2016M590733
文摘Water quenching blast furnace slag （WQBFS） is widely produced in the blast furnace iron making process. It is mainly composed of CoO, MgO, A1203, and SiO2 with low contents of other metal elements such as Fe, Mn, Ti, K and No. In this study, WQBFS was treated with grinding, hydrochloric acid acidification, filtration, filtrate extraction by alkali liquor and a hydration reaction. Then BFS micropowder （BFSMP）, BFS acidified solid （BFSAS） and BFS acid-alkali precipitate （BFSAP） were obtained, which were characterized by X-ray diffrac- tion, scanning electron microscopy, X-ray fluorescence and Brunauer-Emmet-Teller （BET） specific surface area. The decoloration efficiency for Methyl Orange （MO） was used to evaluate the adsorptive ability of the three absorbents. The effects of adsorptive reaction conditions （pH and temperature of solution, reaction time, sorbent dosage and initial concentration） on MO removal were also investigated in detail. The results indicated that BFSAP performed better in MO removal than the other two absorbents. When the pH value of MO solutions was in the range 3.0-13.0, the degradation efficiency of a solution with initial MO concentration of 25 mg/L reached 99.97% for a reaction time of 25 rain at 25℃. The maximum adsorption capacity of BFSAP for MO was 167 mg/g. Based on optimized experiments, the results conformed with the Langrnuir adsorption isotherm and pseudo-second-order kinetics. Among inorganic anions, SO2- and PO4- had significant inhibitory effects on MO removal in BFSAP treatment due to ion-exchange adsorption.
文摘A 13% chromium white iron was produced using a stir cast process. Samples of the produced white iron were austenised at 1450°C and then quenched in water to the room temperature. The characterisation tools such as X-ray diffractometer, scanning electron microscope, Brinell hardness tester and pin on disc machine were employed in the studies of the phase orientation and morphology, hardness value measurement and investigation of wear behaviour. The results revealed that water quenching the 13% chromium white iron led to the precipitation of fine iron chromides and cementite in the matrix of martensite. Moreover, there is an about 22% to 45% increase in hardness values of the as-cast 13% chromium white iron as the %composition of graphite additions increased from 1.36 to 3.04. However, the impact energy values are sacrificed. The increase in hardness values is attributable to hard intermetallic compounds such as iron chromides and cementite phases in the iron matrix. Also, there is an about 32% - 42% increase in hardness values of the heat treated samples of 13% chromium white iron when compared with those of the as-cast. The increased hardness values are attributable to even distribution of the fine intermetallic compounds in the fine grains of martensitic matrix. The wear rate increased as the sliding moments per unit time increased due to increasing work done by the friction to oppose the rotation of the pin on disc. The water quenched 13% chromium white iron samples have greater wear resistances than the as-cast samples due to their greater hardness values than those of the as-cast samples. The effect of speed increase on decreasing wear resistances is more pronounced on the heat treated samples than on the as-cast samples. Hence, the water quenched 13% chromium white iron is an excellent material in application requiring high wear resistance and low impact energy especially in grinding mill liner plate, bottom or casing used in the concrete pipe production, roller for crushing and pulverising mills.
