To solve the problem of difficult utilization of steel slag,the liquid steel slag was modified and the air-quenching granulation process was carried out to make steel slag into a value-added end product:air-quenching ...To solve the problem of difficult utilization of steel slag,the liquid steel slag was modified and the air-quenching granulation process was carried out to make steel slag into a value-added end product:air-quenching granulated steel slag.The granulated slag was tested to analyze the variation rule of slag properties under different modification conditions.Based on the phase diagram of CaO–Si_(2)O–FeO–MgO–Al2O3 slag system,the feasibility of blast furnace(BF)slag as modifier was determined.When the addition of BF slag was increased from 0%to 35%,following results were obtained.The slag fluidity was improved,and the air-quenching temperature range was expanded.Then,the yield of air-quenched steel slag increased,while the granulation rate,the degree of sphericity,the compactness were decreased.Furthermore,the air-quenching granulation process could substantially improve the stability and the amorphous content of steel slag.The maximum removal rate of free CaO was above 80%and the amorphous content was up to 95%.Taking the factors of yield and properties of granulated steel slag into full consideration,the optimum proportion of BF slag is around 15%.展开更多
Specularite concentrates have advantages of high ferrous grade, less harmful impurities and low price. However, the small size and poor granulation behavior of specularite concentrates consequently deteriorate the per...Specularite concentrates have advantages of high ferrous grade, less harmful impurities and low price. However, the small size and poor granulation behavior of specularite concentrates consequently deteriorate the permeability of sinter bed and reduce the productivity of sinter, resulting in un-effective utilization in sintering process. The granulation experiments were carried out when specularite concentrates matched with five kinds of fine or coarse ores, and the effects of surface property and wettability of fine or coarse ores on granulation behavior of specularite concentrates were investigated. Then, the optimized ore blending recipes were proposed to strengthen the granulation behavior of specularite concentrates. The results indicated that the growth index increased with increasing the specific surface area of fine ores and had a positive linear correlation with the circularity degree of coarse ores, whereas negative correlations exist between the growth index and the contact angle of fine or coarse ores. Compared with the concentrates, the growth index increased by approximately 22% scheme of blended ores containing 15 mass% specularite in the case of using Ore-A and Ore-E with greater surface property and higher wettability to replace all of Ore-B and half of Ore-D, respectively. Furthermore, the vertical sintering speed and the productivity of sinter improved by approximately 23% and 20%, respectively.展开更多
Dry centrifugal granulation(DCG)experiments for blast furnace slag(BFS)were performed by means of a rotary disk atomizer since water quenching method can create a series of problems.The results showed that the DCG met...Dry centrifugal granulation(DCG)experiments for blast furnace slag(BFS)were performed by means of a rotary disk atomizer since water quenching method can create a series of problems.The results showed that the DCG method can granulate the BFS,but the results are easily affected by the slag flow rate,disk rotating speed,disk radius,disk material and slag falling height.The granulating parameters with an excessive flow rate,low rotating speed,SiN–SiC disk,stainless steel disk and low slag falling height are detrimental to the granulation process.The most suitable parameters for granulation are a slag flow rate of 5.1×10^(−5) m^(3)/s,a disk rotating speed of 1500–2300 r/min,a slag falling height of 0.8 m and a smooth graphitic disk with the radius of 0.1 m.In the absence of an off-center flow,the overall best granulating effect produces round particles with mean diameter of 3.43 mm without creating slag fiber.The vitreous content of the BFS particles granulated by graphite disks is 92%,which meets the requirements of cement raw materials.The Bond work index of dry granulated BFS is 18.4 kWh/t,and the grindability of dry granulated slag and water-quenched slag is similar.展开更多
基金supported by the Key Research and Development Program of Hebei Province(Grant Number 19273806D)the Project of Hebei Provincial Department of Education(Grant Number JQN2020042).
文摘To solve the problem of difficult utilization of steel slag,the liquid steel slag was modified and the air-quenching granulation process was carried out to make steel slag into a value-added end product:air-quenching granulated steel slag.The granulated slag was tested to analyze the variation rule of slag properties under different modification conditions.Based on the phase diagram of CaO–Si_(2)O–FeO–MgO–Al2O3 slag system,the feasibility of blast furnace(BF)slag as modifier was determined.When the addition of BF slag was increased from 0%to 35%,following results were obtained.The slag fluidity was improved,and the air-quenching temperature range was expanded.Then,the yield of air-quenched steel slag increased,while the granulation rate,the degree of sphericity,the compactness were decreased.Furthermore,the air-quenching granulation process could substantially improve the stability and the amorphous content of steel slag.The maximum removal rate of free CaO was above 80%and the amorphous content was up to 95%.Taking the factors of yield and properties of granulated steel slag into full consideration,the optimum proportion of BF slag is around 15%.
文摘Specularite concentrates have advantages of high ferrous grade, less harmful impurities and low price. However, the small size and poor granulation behavior of specularite concentrates consequently deteriorate the permeability of sinter bed and reduce the productivity of sinter, resulting in un-effective utilization in sintering process. The granulation experiments were carried out when specularite concentrates matched with five kinds of fine or coarse ores, and the effects of surface property and wettability of fine or coarse ores on granulation behavior of specularite concentrates were investigated. Then, the optimized ore blending recipes were proposed to strengthen the granulation behavior of specularite concentrates. The results indicated that the growth index increased with increasing the specific surface area of fine ores and had a positive linear correlation with the circularity degree of coarse ores, whereas negative correlations exist between the growth index and the contact angle of fine or coarse ores. Compared with the concentrates, the growth index increased by approximately 22% scheme of blended ores containing 15 mass% specularite in the case of using Ore-A and Ore-E with greater surface property and higher wettability to replace all of Ore-B and half of Ore-D, respectively. Furthermore, the vertical sintering speed and the productivity of sinter improved by approximately 23% and 20%, respectively.
基金This work was financially supported by the National Key Research and Development Program of China(2018YFC1900602)the Open Youth Fund of the State key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology(2018QN03).
文摘Dry centrifugal granulation(DCG)experiments for blast furnace slag(BFS)were performed by means of a rotary disk atomizer since water quenching method can create a series of problems.The results showed that the DCG method can granulate the BFS,but the results are easily affected by the slag flow rate,disk rotating speed,disk radius,disk material and slag falling height.The granulating parameters with an excessive flow rate,low rotating speed,SiN–SiC disk,stainless steel disk and low slag falling height are detrimental to the granulation process.The most suitable parameters for granulation are a slag flow rate of 5.1×10^(−5) m^(3)/s,a disk rotating speed of 1500–2300 r/min,a slag falling height of 0.8 m and a smooth graphitic disk with the radius of 0.1 m.In the absence of an off-center flow,the overall best granulating effect produces round particles with mean diameter of 3.43 mm without creating slag fiber.The vitreous content of the BFS particles granulated by graphite disks is 92%,which meets the requirements of cement raw materials.The Bond work index of dry granulated BFS is 18.4 kWh/t,and the grindability of dry granulated slag and water-quenched slag is similar.
