Reaction behaviors of sulfur and iron compounds in sodium aluminate solutions were investigated. The results show that iron compounds can remarkably remove the S2 but cannot get rid of S2Oc2-, SO^2- and SO4^-2 in sodi...Reaction behaviors of sulfur and iron compounds in sodium aluminate solutions were investigated. The results show that iron compounds can remarkably remove the S2 but cannot get rid of S2Oc2-, SO^2- and SO4^-2 in sodium aluminate solutions. The removal efficiency of S^2- using ferrous compound and ferric compound can reach 86.10% and 92.70% respectively when the iron compounds were added with a molar ratio of 2：1 compared with the sulfur in liquors at 100℃. Moreover, several same compounds are formed in those two desulfurization processes with ferrous or ferric compounds, including erdite, hematite, amorphous ferrous sulfide, polymerized sulfur-iron compounds and ferric sulfate. The major difference between these two processes is that the erdite generated from ferrous compounds at the initial reaction stage will convert to a sodium-free product FeS2 at the subsequent stage.展开更多
Chemical conditioning was used to modify the triboelectrification of coal and mineral particles.The chemicals tested included starch,lignin,kerosene,ethanol,acetic acid,salicylic acid,sodium oleate,Sodium Hexametaphos...Chemical conditioning was used to modify the triboelectrification of coal and mineral particles.The chemicals tested included starch,lignin,kerosene,ethanol,acetic acid,salicylic acid,sodium oleate,Sodium Hexametaphosphate(SH),sodium silicate, Sodium Dodecylbenzenesulfonate(SDBS),Sodium Bicarbonate(SB) and ammonia.A high-speed,dry mixing method was employed.The charge-to-mass ratio of the coal and mineral samples,both untreated and treated,was tested using a Faraday cup. Dielectric constants were determined by measuring capacitance.It is found that the selectivity of the additives toward coal or minerals is not consistent.Salicylic acid is the optimal additive to enhance the triboelectrification performance of coal samples.Starch, lignin and sodium oleate are suitable for removal of pyrite.SH,sodium silicate,SDBS,SB and ammonia are suitable additives for the removal of ash-forming minerals.展开更多
Direct reduction is an emerging technology for ferric bauxite utilization. However, because of sodium volatilization, its sodium carbonate consumption is considerably higher than that in ordinary bauxite processing te...Direct reduction is an emerging technology for ferric bauxite utilization. However, because of sodium volatilization, its sodium carbonate consumption is considerably higher than that in ordinary bauxite processing technology. TG-DSC and XRD were applied to detecting phase transformation and mass loss in direct reduction to reveal the mechanism on sodium volatilization. The results show that the most significant influence factor of ferric bauxite on sodium volatilization in direct reduction system is its iron content. Sodium volatilization is probably ascribed to the instability of amorphous substances structure. Amorphous substances are the intermediate-products of the reaction, and the volatilization rate of sodium increases with its generating rate. These amorphous substances are volatile, thus, more sodium is volatilized with its generation. A small amount of amorphous substances are generated in the reaction between Na2CO3 and Al2O3; thus, only 3.15% of sodium is volatilized. Similarly, the volatilization rate is 1.87% in the reaction between Na2CO3 and SiO2. However, the volatilization rate reaches 7.64% in the reaction between Na2CO3 and Fe2O3 because of the generation of a large amount of amorphous substances.展开更多
The structural changes of silicate anions in the desilication process with the addition of calcium hydrate alumino-carbonate were studied by measuring Raman spectra, infrared spectra and corresponding second derivativ...The structural changes of silicate anions in the desilication process with the addition of calcium hydrate alumino-carbonate were studied by measuring Raman spectra, infrared spectra and corresponding second derivative spectra. The results show that the desilication ratio in the solution prepared by the addition of sodium silicate(solution-SS) is much greater than that in the solution by the addition of green liquor(solution-GL), and low alumina concentration in the sodium aluminate solutions facilitates the desilication process. It is also shown that alumino-silicate anions in the solution-GL, and Q^3 polymeric silicate anions in solution-SS are predominant, respectively. In addition, increasing the concentration of silica favors respectively the formation of the alumino-silicate or the Q^3 silicate anions in the solution-GL or the solution-SS. Therefore, it can be inferred that the low desilication ratio in the silicate-bearing aluminate solution is mainly attributed to the existence of alumino-silicate anions.展开更多
In light of characteristic of low quality feldspar ores in Wanzai County,Jiangxi Province,steel ball was taken as grinding medium,and selective grinding could make impurity separate from feldspar effectively. Through ...In light of characteristic of low quality feldspar ores in Wanzai County,Jiangxi Province,steel ball was taken as grinding medium,and selective grinding could make impurity separate from feldspar effectively. Through the flow of flotation-desliming-high gradient magnetic separation,the feldspar Concentration 1 was obtained with the yield of 70.19 %,containing Fe2O3 0.17 % and TiO2 0.07 %. The feldspar Concentrate 1 could meet the quality requirement of high-grade construction ceramic. And the slime that was deslimed in the flow was also separated and recovered; the feldspar Concentration 2 was obtained with the yield of 13.18 %,containing Fe2O3 0.31 % and TiO2 0.17 %. The feldspar Concentrate 2 can be used for raw material of low-end ceramic. And gangue,with the yield of 16.63 %,was thrown away in this flow,the separating efficiency was high. Employing this flow could also bring high economy benefit and low influence of pollution to environment.展开更多
Minerals which enter lake-marsh ores composition are very diverse. There are two large classes of ores： ferrous and manganese-ferrous ores. Each class is divided into groups according to its mineral composition. In t...Minerals which enter lake-marsh ores composition are very diverse. There are two large classes of ores： ferrous and manganese-ferrous ores. Each class is divided into groups according to its mineral composition. In this investigation, ferrous ore sample （Chagodostcha） and manganese-ferrous ore samples （Totyma-2 and Mologa-2） were considered. All samples in the initial state are contaminated with a-quartz and Ab-An feldspars. Thus for purification of the samples, direct flotation method with kerosene agent were used. As a result, almost all impurities were removed from the samples. With the X-ray diffraction method, the authors identified following phases： goethite （ferrous ore） and birnessite （manganese-ferrous ores）. Also, the authors used electron probe microanalysis of the original and purified probes and it showed the presence of such impurities as Ca, K, Mg and Ba in birnessite from the manganese-ferrous ores, and AI and Mn impurities in goethite from the ferrous ore. All ore minerals are in a nanocrystalline state （crystallite size is about 10 nm）.展开更多
基金Project(51374239)supported by the National Natural Science Foundation of China
文摘Reaction behaviors of sulfur and iron compounds in sodium aluminate solutions were investigated. The results show that iron compounds can remarkably remove the S2 but cannot get rid of S2Oc2-, SO^2- and SO4^-2 in sodium aluminate solutions. The removal efficiency of S^2- using ferrous compound and ferric compound can reach 86.10% and 92.70% respectively when the iron compounds were added with a molar ratio of 2：1 compared with the sulfur in liquors at 100℃. Moreover, several same compounds are formed in those two desulfurization processes with ferrous or ferric compounds, including erdite, hematite, amorphous ferrous sulfide, polymerized sulfur-iron compounds and ferric sulfate. The major difference between these two processes is that the erdite generated from ferrous compounds at the initial reaction stage will convert to a sodium-free product FeS2 at the subsequent stage.
基金supported by the National Natural Science Foundation of China(No. 50921002)the Key Laboratory of Coal Processing and Efficient Utilization,the Ministry of Education of China(No.CPEUKF08-05).
文摘Chemical conditioning was used to modify the triboelectrification of coal and mineral particles.The chemicals tested included starch,lignin,kerosene,ethanol,acetic acid,salicylic acid,sodium oleate,Sodium Hexametaphosphate(SH),sodium silicate, Sodium Dodecylbenzenesulfonate(SDBS),Sodium Bicarbonate(SB) and ammonia.A high-speed,dry mixing method was employed.The charge-to-mass ratio of the coal and mineral samples,both untreated and treated,was tested using a Faraday cup. Dielectric constants were determined by measuring capacitance.It is found that the selectivity of the additives toward coal or minerals is not consistent.Salicylic acid is the optimal additive to enhance the triboelectrification performance of coal samples.Starch, lignin and sodium oleate are suitable for removal of pyrite.SH,sodium silicate,SDBS,SB and ammonia are suitable additives for the removal of ash-forming minerals.
基金Project(51304012)supported by the National Natural Science Foundation of ChinaProject(2014M550845)supported by China Postdoctoral Science FoundationProject(KF13-05)supported by Open Foundation of the State Key Laboratory of Advanced Metallurgy(USTB),China
文摘Direct reduction is an emerging technology for ferric bauxite utilization. However, because of sodium volatilization, its sodium carbonate consumption is considerably higher than that in ordinary bauxite processing technology. TG-DSC and XRD were applied to detecting phase transformation and mass loss in direct reduction to reveal the mechanism on sodium volatilization. The results show that the most significant influence factor of ferric bauxite on sodium volatilization in direct reduction system is its iron content. Sodium volatilization is probably ascribed to the instability of amorphous substances structure. Amorphous substances are the intermediate-products of the reaction, and the volatilization rate of sodium increases with its generating rate. These amorphous substances are volatile, thus, more sodium is volatilized with its generation. A small amount of amorphous substances are generated in the reaction between Na2CO3 and Al2O3; thus, only 3.15% of sodium is volatilized. Similarly, the volatilization rate is 1.87% in the reaction between Na2CO3 and SiO2. However, the volatilization rate reaches 7.64% in the reaction between Na2CO3 and Fe2O3 because of the generation of a large amount of amorphous substances.
基金Project(51274242)supported by the National Natural Science Foundation of ChinaProject(2015CX001)supported by the Innovation-driven Plan in Central South University,China
文摘The structural changes of silicate anions in the desilication process with the addition of calcium hydrate alumino-carbonate were studied by measuring Raman spectra, infrared spectra and corresponding second derivative spectra. The results show that the desilication ratio in the solution prepared by the addition of sodium silicate(solution-SS) is much greater than that in the solution by the addition of green liquor(solution-GL), and low alumina concentration in the sodium aluminate solutions facilitates the desilication process. It is also shown that alumino-silicate anions in the solution-GL, and Q^3 polymeric silicate anions in solution-SS are predominant, respectively. In addition, increasing the concentration of silica favors respectively the formation of the alumino-silicate or the Q^3 silicate anions in the solution-GL or the solution-SS. Therefore, it can be inferred that the low desilication ratio in the silicate-bearing aluminate solution is mainly attributed to the existence of alumino-silicate anions.
基金support from Jiangxi New Wuzhou In-dustrial Minerals Co. Ltd
文摘In light of characteristic of low quality feldspar ores in Wanzai County,Jiangxi Province,steel ball was taken as grinding medium,and selective grinding could make impurity separate from feldspar effectively. Through the flow of flotation-desliming-high gradient magnetic separation,the feldspar Concentration 1 was obtained with the yield of 70.19 %,containing Fe2O3 0.17 % and TiO2 0.07 %. The feldspar Concentrate 1 could meet the quality requirement of high-grade construction ceramic. And the slime that was deslimed in the flow was also separated and recovered; the feldspar Concentration 2 was obtained with the yield of 13.18 %,containing Fe2O3 0.31 % and TiO2 0.17 %. The feldspar Concentrate 2 can be used for raw material of low-end ceramic. And gangue,with the yield of 16.63 %,was thrown away in this flow,the separating efficiency was high. Employing this flow could also bring high economy benefit and low influence of pollution to environment.
文摘Minerals which enter lake-marsh ores composition are very diverse. There are two large classes of ores： ferrous and manganese-ferrous ores. Each class is divided into groups according to its mineral composition. In this investigation, ferrous ore sample （Chagodostcha） and manganese-ferrous ore samples （Totyma-2 and Mologa-2） were considered. All samples in the initial state are contaminated with a-quartz and Ab-An feldspars. Thus for purification of the samples, direct flotation method with kerosene agent were used. As a result, almost all impurities were removed from the samples. With the X-ray diffraction method, the authors identified following phases： goethite （ferrous ore） and birnessite （manganese-ferrous ores）. Also, the authors used electron probe microanalysis of the original and purified probes and it showed the presence of such impurities as Ca, K, Mg and Ba in birnessite from the manganese-ferrous ores, and AI and Mn impurities in goethite from the ferrous ore. All ore minerals are in a nanocrystalline state （crystallite size is about 10 nm）.
