In order to avoid the waste of iron caused by the direct use of ferronickel slag(FNS)in building materials,the effects of reduction iron extraction on the physical and chemical properties,cementitious reactivity and h...In order to avoid the waste of iron caused by the direct use of ferronickel slag(FNS)in building materials,the effects of reduction iron extraction on the physical and chemical properties,cementitious reactivity and hydration reaction characteristics of FNS and ferrum extraction tailing of nickel slag(FETNS)were studied.The experimental results show that the reduction ferrum extraction method changes the mineral phase composition of the waste slag,breaks the Si-O-Si bond,forms the tetrahedral structure of Si-O-NBO or Si-O-2NBO,and increases the content of active components such as Ca,Si,Mg,and Al.Compared with FNS,the 28 d compressive strength of pastes prepared by FETNS increases by 16.12%,22.57%,33.13%,44.26%,and 57.65%,respectively.The degree of hydration reaction of the composite cementitious systems in the FETNS group is higher than that in the FNS group at different ages,and the content of hydration products such as C-S-H gel and ettringite(AFt)is also higher than that in the FNS group.More hydration products can improve the curing ability to Cr and Mn of the composite cementitious systems in the FETNS group,and reduce the leaching value of Cr and Mn.展开更多
The sticking phenomenon between molten slag and refractory is one of the crucial problems when preparing ferronickel from laterite ore using rotary hearth fulnace or rotary kiln processes. This study aims to ameliorat...The sticking phenomenon between molten slag and refractory is one of the crucial problems when preparing ferronickel from laterite ore using rotary hearth fulnace or rotary kiln processes. This study aims to ameliorate sticking problems by using silicon dioxide （SiO2） to adjust the melting degree of file briquette during reduction roasting. Thermodynamic analysis indicates that the melting temperature of the slag gradually increases with an increase in the SiO2 proportion （SiO2/（SiO2 ＋ A1203 ＋ MgO） mass ratio）. Experimental validations also prove that the briquette retains its original shape when the SiO2 proportion is greater than 75wt%, and sticking problems axe avoided during reduction. A ferronickel product with 8.33wt% Ni and 84.71wt% Fe was prepared via reductive roasting at 1500~C for 90 min with a SiO2 proportion of 75wt% and a C/O molar ratio of 1.0 followed by dry magnetic separation; the corresponding recoveries of Ni and Fe reached 75.70% and 77.97%, respectively. The micro stxucture and phase txmlsformation of reduced briquette reveals that the aggregation and growth of ferroinckel particles were not significantly affected after adding SiO2 to the reduction process.展开更多
The thermal behaviors of single laterite ore and graphite-laterite mixtures were investigated by thermogravimetry （TG）, derivative thermogravimetry （DTG）, and differential thermal analysis （DTA）. Four mass loss ...The thermal behaviors of single laterite ore and graphite-laterite mixtures were investigated by thermogravimetry （TG）, derivative thermogravimetry （DTG）, and differential thermal analysis （DTA）. Four mass loss steps maximized at about 78, 272, 583, and 826℃ are observed for the laterite ore, representing the vaporization of free water, the dehydroxylation of goethite, the decomposition of serpentines, and the second dehydroxylation of serpentines, respectively. The reduction reactions of the graphite-laterite mixtures start at around 700℃ and can be divided into three major temperature regions. Coal-laterite composites with an addition of 10 wt.% CaO were roasted at 1100-1350℃ for 30 min, and the reduced samples were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results indi- cate that the reduction reactions proceed more completely at higher temperatures. The growth of the reduced ferronickel particles is greatly influenced by the roasting temperature, Obvious growth of the reduced ferronickel particles appears with the formation of worm-like crystals for the sample reduced at 1250℃ and spheric particles are observed for the sample reduced at 1300℃. When the reduction temperature increases to 1350℃, the reduced ferronickel particles agglomerate to ferronickel granules of 3-8 mm in diameter. The main elements in the granules include iron, nickel, chromium, carbon, and sulfur, with the content of nickel and that of iron of 9.08 wt.% and 85.21 wt.%, respectively.展开更多
The method of producing ferronickel at low temperature(1250–1400℃)has been applied since the 1950s at Nippon Yakin Kogyo,Oheyama Works,Japan.Limestone was used as an additive to adjust the slag composition for lower...The method of producing ferronickel at low temperature(1250–1400℃)has been applied since the 1950s at Nippon Yakin Kogyo,Oheyama Works,Japan.Limestone was used as an additive to adjust the slag composition for lowering the slag melting point.The ferronickel product was recovered by means of a magnetic separator from semi-molten slag and metal after water quenching.To increase the efficiency of magnetic separation,a large particle size of ferronickel is desired.Therefore,in this study,the influences of CaO,CaF_(2),and H_(3)BO_(3) additives on the evolution of ferronickel particle at≤1250℃were investigated.The experiments were conducted at 900–1250℃with the addition of CaO,CaF_(2),and H_(3)BO_(3).The reduction processes were carried out in a horizontal tube furnace for 2 h under argon atmosphere.At 1250℃,with the CaO addition of 10 wt%of the ore weight,ferronickel particles with size of 20μm were obtained.The ferronickel particle size increased to 165μm by adding 10 wt%CaO and 10 wt%CaF_(2).The addition of boric acid further increased the ferronickel particle size to 376μm,as shown by the experiments with the addition of 10 wt%CaO,10 wt%CaF_(2),and 10 wt%H_(3)BO_(3).展开更多
Petroleum coke is industrial solid wastes and its disposal and storage has been a great challenge to the environment. In this study, petroleum coke was utilized as a novel co-reduction reductant of low-grade laterite ...Petroleum coke is industrial solid wastes and its disposal and storage has been a great challenge to the environment. In this study, petroleum coke was utilized as a novel co-reduction reductant of low-grade laterite ore and red mud. A ferronickel product of 1.98wt% nickel and 87.98wt% iron was obtained with 20wt% petroleum coke, when the roasting temperature and time was 1250°C and 60 min, respectively. The corresponding recoveries of nickel and total iron were 99.54wt% and 95.59wt%, respectively. Scanning electron microscopy-energy dis- persive spectrometry (SEM-EDS) analysis showed metallic nickel and iron mainly existed in the form of ferronickel particles which distrib- uted uniformly at a size of approximately 30 μm with high purity. This study demonstrated that petroleum coke is a promising reductant in the co-reduction of laterite ore and red mud. Compared to other alternatives, petroleum coke is advantageous with reduced production cost and high applicability in anthracite-deficient areas.展开更多
The preparation of ferronickel alloy from the nickel laterite ore with low Co and high MgO contents was studied by using a pre-reduction-smelting method. The effects of reduction time, calcination temperature, quantit...The preparation of ferronickel alloy from the nickel laterite ore with low Co and high MgO contents was studied by using a pre-reduction-smelting method. The effects of reduction time, calcination temperature, quantity of reductant and calcium oxide (CaO), and pellet diameter on the reduction ratio of Fe and on the pellet strength were investigated. The results show that, for a roasting temperature > 800 A degrees C, a roasting time > 30 min, 1.5wt% added anthracite coal, 5wt% added CaO, and a pellet size of similar to 10 mm, the reduction ratio of Fe exceeds 70% and the compressive strength of the pellets exceeds 10 kg per pellet. Reduction smelting experiments were performed by varying the smelting time, temperature, quantity of reductant and CaO, and reduction ratio of Fe in the pellets. Optimal conditions for the reduction smelting process are as follows: smelting time, 30-45 min; smelting temperature, 1550A degrees C; quantity of reductant, 4wt%-5wt%; and quantity of CaO, 5wt%; leading to an Fe reduction ratio of 75% in the pellets. In addition, the mineral composition of the raw ore and that during the reduction process were investigated by process mineralogy.展开更多
Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the n...Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the nickel content in ferronickel about the laterite nickel ore, was from Philippines and contented low nickel, high iron and aluminum. The results showed that if the C/O mole ratio was not higher than 0.5 and the reduction temperature was kept as 1200°C and then increased up to 1500°C, the metal could not separate from molten slag for the A series of experiments, which were only added CaF<sub>2</sub>. However, when the C/O ratio was added up to 0.6 - 0.8, the metal could separate well from the slag, and the yields of Fe and Ni increased gradually. But the nickel content in the metal declined from 1.79% to 1.34%. When the C/O ratio increased to 1.2, and the temperature of melting products obtained at 1200°C and rose to 1550°C, the separation of metal from slag could not be realized in B group of tests, which were only added hydrated lime. However, when both of CaF<sub>2</sub> and hydrated lime were added, the metal could separate from slag in C group. In order to increase the content of nickel in the metal, it is necessary to restrain the reduction of iron oxide. When the C/O mole ratio is 0.6, the nickel content of metal could be 1.79%, which was higher than the theoretical ratio 1.65% of Ni/(Ni + Fe) of the latcritic nickel ore, but the yield of nickle was only 71.3%.展开更多
This study aimed to assess the differences of characteristics between the new ferronickel slag generated from the production of nickel and the slag which had been used as a material reclamation. The Toxicity Character...This study aimed to assess the differences of characteristics between the new ferronickel slag generated from the production of nickel and the slag which had been used as a material reclamation. The Toxicity Characteristic Leaching Procedure (TCLP) test was conducted on ferronickel slag to determine the concentration of heavy metals leaching. Then, the tests of X-Ray Diffraction (XRD), Scanning Electron Microscopic (SEM) and Energy-Dispersive X-Ray Spectroscopy (EDX) are also conducted on the ferronickel slag samples. The results of TCLP test show that the new ferronickel slag samples contain Fe (158, 6775 ppm), Cr (0.64465 ppm), and Pb (0.0219 ppm), and that the ferronickel slag has been used as a reclamation material containing Fe (3.94 ppm) and Cr (2.91 ppm). The result of EDX test shows that the slag sample from the reclamation area contains higher Ni concentration than the new slag sample. Slag that has been used for reclamation contains high SiO2 and Mg2(SiO6). The XRD analysis result shows that the highest elements in the slag are Si and Mg with 18.94% and 15.83% respectively. The dominant mineral in the slag is forsterite (Mg 1.784 FeSiO4 0216) by 41% and the rest is magnesium silicate (Mg2(SiO6)).展开更多
The effect of the Al2O3 content and basicity (the molar ratio of MgO to SiO2) on the viscosity of a SiO2-MgO-FeOAl2O3-CaO slag was studied to fully understand the smelting process of the ferronickel alloy. Experimenta...The effect of the Al2O3 content and basicity (the molar ratio of MgO to SiO2) on the viscosity of a SiO2-MgO-FeOAl2O3-CaO slag was studied to fully understand the smelting process of the ferronickel alloy. Experimental results show that the slag is a mixture of liquid and solid phases at the experimental temperature. The viscosity decreased as the basicity increased and increased as the Al2O3 content increased. To determine the effect of the Al2O3 content and basicity on the structure of the molten slag, Raman spectroscopy was performed on the slag sample, which was quenched from the high temperature with water. The Raman spectra showed that the fractions of the polymerization structural units decreased significantly as the basicity of the slag increased, resulting in a decrease in the apparent viscosity. However, Al2O3 acts as a network former in the slag system, thereby making the slag structure further polymerized and increasing the viscosity.展开更多
Traditionally, fluxes containing calcium fluoride and other additives are used for the treatment of hot metal and molten steel. Recently, magnesium powder or lime-Mg mixture is used more popularly in hot metal desulph...Traditionally, fluxes containing calcium fluoride and other additives are used for the treatment of hot metal and molten steel. Recently, magnesium powder or lime-Mg mixture is used more popularly in hot metal desulphurization. However, the use of calcium fluoride has been restricted due to environmental concerns, and the supply of magnesium is uncertain for the countries, which are short of magnesium resource. For those reasons, calcium aluminate fluxes are a possible alternative to replace slags containing calcium fluoride or magnesium. Calcium aluminate fluxes can be produced from three different raw materials: (1) high-quality bauxite, (2) residuals from aluminum dross treatment processes and (3) waste products from alumina production. Due to the limited amount and high cost associated with high-quality bauxite, the other two sources are preferred based on both economic and environmental considerations. The objective of this paper is to examine the use of waste slags and by-products from the aluminum industry as potential refining fluxes for the steel industry so that waste disposal from the aluminum industry can be reduced with economical and environmental benefits for both industrial sectors.展开更多
基金Funded by the Science and Technology Program of Gansu Province(Nos.23JRRA799 and 24JRRA213)the National Natural Science Foundation of China(Nos.52178216,52008196,and U21A20150)。
文摘In order to avoid the waste of iron caused by the direct use of ferronickel slag(FNS)in building materials,the effects of reduction iron extraction on the physical and chemical properties,cementitious reactivity and hydration reaction characteristics of FNS and ferrum extraction tailing of nickel slag(FETNS)were studied.The experimental results show that the reduction ferrum extraction method changes the mineral phase composition of the waste slag,breaks the Si-O-Si bond,forms the tetrahedral structure of Si-O-NBO or Si-O-2NBO,and increases the content of active components such as Ca,Si,Mg,and Al.Compared with FNS,the 28 d compressive strength of pastes prepared by FETNS increases by 16.12%,22.57%,33.13%,44.26%,and 57.65%,respectively.The degree of hydration reaction of the composite cementitious systems in the FETNS group is higher than that in the FNS group at different ages,and the content of hydration products such as C-S-H gel and ettringite(AFt)is also higher than that in the FNS group.More hydration products can improve the curing ability to Cr and Mn of the composite cementitious systems in the FETNS group,and reduce the leaching value of Cr and Mn.
基金the National Natural Science Foundation of China(No.51234010)the Fundamental Research Funds for Central Universities(No.106112017CDJXY130001)for the financial support provided for this research
文摘The sticking phenomenon between molten slag and refractory is one of the crucial problems when preparing ferronickel from laterite ore using rotary hearth fulnace or rotary kiln processes. This study aims to ameliorate sticking problems by using silicon dioxide （SiO2） to adjust the melting degree of file briquette during reduction roasting. Thermodynamic analysis indicates that the melting temperature of the slag gradually increases with an increase in the SiO2 proportion （SiO2/（SiO2 ＋ A1203 ＋ MgO） mass ratio）. Experimental validations also prove that the briquette retains its original shape when the SiO2 proportion is greater than 75wt%, and sticking problems axe avoided during reduction. A ferronickel product with 8.33wt% Ni and 84.71wt% Fe was prepared via reductive roasting at 1500~C for 90 min with a SiO2 proportion of 75wt% and a C/O molar ratio of 1.0 followed by dry magnetic separation; the corresponding recoveries of Ni and Fe reached 75.70% and 77.97%, respectively. The micro stxucture and phase txmlsformation of reduced briquette reveals that the aggregation and growth of ferroinckel particles were not significantly affected after adding SiO2 to the reduction process.
文摘The thermal behaviors of single laterite ore and graphite-laterite mixtures were investigated by thermogravimetry （TG）, derivative thermogravimetry （DTG）, and differential thermal analysis （DTA）. Four mass loss steps maximized at about 78, 272, 583, and 826℃ are observed for the laterite ore, representing the vaporization of free water, the dehydroxylation of goethite, the decomposition of serpentines, and the second dehydroxylation of serpentines, respectively. The reduction reactions of the graphite-laterite mixtures start at around 700℃ and can be divided into three major temperature regions. Coal-laterite composites with an addition of 10 wt.% CaO were roasted at 1100-1350℃ for 30 min, and the reduced samples were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results indi- cate that the reduction reactions proceed more completely at higher temperatures. The growth of the reduced ferronickel particles is greatly influenced by the roasting temperature, Obvious growth of the reduced ferronickel particles appears with the formation of worm-like crystals for the sample reduced at 1250℃ and spheric particles are observed for the sample reduced at 1300℃. When the reduction temperature increases to 1350℃, the reduced ferronickel particles agglomerate to ferronickel granules of 3-8 mm in diameter. The main elements in the granules include iron, nickel, chromium, carbon, and sulfur, with the content of nickel and that of iron of 9.08 wt.% and 85.21 wt.%, respectively.
基金the Program of Research,Community Service,and Innovation of the Institut Teknologi Bandung(P3MI–ITB)for funding this research。
文摘The method of producing ferronickel at low temperature(1250–1400℃)has been applied since the 1950s at Nippon Yakin Kogyo,Oheyama Works,Japan.Limestone was used as an additive to adjust the slag composition for lowering the slag melting point.The ferronickel product was recovered by means of a magnetic separator from semi-molten slag and metal after water quenching.To increase the efficiency of magnetic separation,a large particle size of ferronickel is desired.Therefore,in this study,the influences of CaO,CaF_(2),and H_(3)BO_(3) additives on the evolution of ferronickel particle at≤1250℃were investigated.The experiments were conducted at 900–1250℃with the addition of CaO,CaF_(2),and H_(3)BO_(3).The reduction processes were carried out in a horizontal tube furnace for 2 h under argon atmosphere.At 1250℃,with the CaO addition of 10 wt%of the ore weight,ferronickel particles with size of 20μm were obtained.The ferronickel particle size increased to 165μm by adding 10 wt%CaO and 10 wt%CaF_(2).The addition of boric acid further increased the ferronickel particle size to 376μm,as shown by the experiments with the addition of 10 wt%CaO,10 wt%CaF_(2),and 10 wt%H_(3)BO_(3).
基金the National Nat-ural Science Foundation of China(No.51874017).
文摘Petroleum coke is industrial solid wastes and its disposal and storage has been a great challenge to the environment. In this study, petroleum coke was utilized as a novel co-reduction reductant of low-grade laterite ore and red mud. A ferronickel product of 1.98wt% nickel and 87.98wt% iron was obtained with 20wt% petroleum coke, when the roasting temperature and time was 1250°C and 60 min, respectively. The corresponding recoveries of nickel and total iron were 99.54wt% and 95.59wt%, respectively. Scanning electron microscopy-energy dis- persive spectrometry (SEM-EDS) analysis showed metallic nickel and iron mainly existed in the form of ferronickel particles which distrib- uted uniformly at a size of approximately 30 μm with high purity. This study demonstrated that petroleum coke is a promising reductant in the co-reduction of laterite ore and red mud. Compared to other alternatives, petroleum coke is advantageous with reduced production cost and high applicability in anthracite-deficient areas.
基金financially supported by the National Natural Science Foundation of China(Nos.U1302274 and 51274044)
文摘The preparation of ferronickel alloy from the nickel laterite ore with low Co and high MgO contents was studied by using a pre-reduction-smelting method. The effects of reduction time, calcination temperature, quantity of reductant and calcium oxide (CaO), and pellet diameter on the reduction ratio of Fe and on the pellet strength were investigated. The results show that, for a roasting temperature > 800 A degrees C, a roasting time > 30 min, 1.5wt% added anthracite coal, 5wt% added CaO, and a pellet size of similar to 10 mm, the reduction ratio of Fe exceeds 70% and the compressive strength of the pellets exceeds 10 kg per pellet. Reduction smelting experiments were performed by varying the smelting time, temperature, quantity of reductant and CaO, and reduction ratio of Fe in the pellets. Optimal conditions for the reduction smelting process are as follows: smelting time, 30-45 min; smelting temperature, 1550A degrees C; quantity of reductant, 4wt%-5wt%; and quantity of CaO, 5wt%; leading to an Fe reduction ratio of 75% in the pellets. In addition, the mineral composition of the raw ore and that during the reduction process were investigated by process mineralogy.
文摘Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the nickel content in ferronickel about the laterite nickel ore, was from Philippines and contented low nickel, high iron and aluminum. The results showed that if the C/O mole ratio was not higher than 0.5 and the reduction temperature was kept as 1200°C and then increased up to 1500°C, the metal could not separate from molten slag for the A series of experiments, which were only added CaF<sub>2</sub>. However, when the C/O ratio was added up to 0.6 - 0.8, the metal could separate well from the slag, and the yields of Fe and Ni increased gradually. But the nickel content in the metal declined from 1.79% to 1.34%. When the C/O ratio increased to 1.2, and the temperature of melting products obtained at 1200°C and rose to 1550°C, the separation of metal from slag could not be realized in B group of tests, which were only added hydrated lime. However, when both of CaF<sub>2</sub> and hydrated lime were added, the metal could separate from slag in C group. In order to increase the content of nickel in the metal, it is necessary to restrain the reduction of iron oxide. When the C/O mole ratio is 0.6, the nickel content of metal could be 1.79%, which was higher than the theoretical ratio 1.65% of Ni/(Ni + Fe) of the latcritic nickel ore, but the yield of nickle was only 71.3%.
文摘This study aimed to assess the differences of characteristics between the new ferronickel slag generated from the production of nickel and the slag which had been used as a material reclamation. The Toxicity Characteristic Leaching Procedure (TCLP) test was conducted on ferronickel slag to determine the concentration of heavy metals leaching. Then, the tests of X-Ray Diffraction (XRD), Scanning Electron Microscopic (SEM) and Energy-Dispersive X-Ray Spectroscopy (EDX) are also conducted on the ferronickel slag samples. The results of TCLP test show that the new ferronickel slag samples contain Fe (158, 6775 ppm), Cr (0.64465 ppm), and Pb (0.0219 ppm), and that the ferronickel slag has been used as a reclamation material containing Fe (3.94 ppm) and Cr (2.91 ppm). The result of EDX test shows that the slag sample from the reclamation area contains higher Ni concentration than the new slag sample. Slag that has been used for reclamation contains high SiO2 and Mg2(SiO6). The XRD analysis result shows that the highest elements in the slag are Si and Mg with 18.94% and 15.83% respectively. The dominant mineral in the slag is forsterite (Mg 1.784 FeSiO4 0216) by 41% and the rest is magnesium silicate (Mg2(SiO6)).
基金the National Natural Science Foundation of China(Grant No.51234010)the Fundamental Research Funds for the Central Universities(Project Nos.2018CDXYCL0018 and 2018CDPTCG0001/11)for the financial support of this research.
文摘The effect of the Al2O3 content and basicity (the molar ratio of MgO to SiO2) on the viscosity of a SiO2-MgO-FeOAl2O3-CaO slag was studied to fully understand the smelting process of the ferronickel alloy. Experimental results show that the slag is a mixture of liquid and solid phases at the experimental temperature. The viscosity decreased as the basicity increased and increased as the Al2O3 content increased. To determine the effect of the Al2O3 content and basicity on the structure of the molten slag, Raman spectroscopy was performed on the slag sample, which was quenched from the high temperature with water. The Raman spectra showed that the fractions of the polymerization structural units decreased significantly as the basicity of the slag increased, resulting in a decrease in the apparent viscosity. However, Al2O3 acts as a network former in the slag system, thereby making the slag structure further polymerized and increasing the viscosity.
文摘Traditionally, fluxes containing calcium fluoride and other additives are used for the treatment of hot metal and molten steel. Recently, magnesium powder or lime-Mg mixture is used more popularly in hot metal desulphurization. However, the use of calcium fluoride has been restricted due to environmental concerns, and the supply of magnesium is uncertain for the countries, which are short of magnesium resource. For those reasons, calcium aluminate fluxes are a possible alternative to replace slags containing calcium fluoride or magnesium. Calcium aluminate fluxes can be produced from three different raw materials: (1) high-quality bauxite, (2) residuals from aluminum dross treatment processes and (3) waste products from alumina production. Due to the limited amount and high cost associated with high-quality bauxite, the other two sources are preferred based on both economic and environmental considerations. The objective of this paper is to examine the use of waste slags and by-products from the aluminum industry as potential refining fluxes for the steel industry so that waste disposal from the aluminum industry can be reduced with economical and environmental benefits for both industrial sectors.
