Sulfuric acid leaching process was applied to extract nickel from roasting-dissolving residue of a spent catalyst, the effect of different parameters on nickel extraction was investigated by leaching experiments, and ...Sulfuric acid leaching process was applied to extract nickel from roasting-dissolving residue of a spent catalyst, the effect of different parameters on nickel extraction was investigated by leaching experiments, and the leaching kinetics of nickel was analyzed. The experimental results indicate that the effects of particle size and sulfuric acid concentration on the nickel extraction are remarkable; the effect of reaction temperature is mild; while the effect of stirring speed in the range of 400-1 200 r/min is negligible. Decreasing particle size or increasing sulfuric acid concentration and reaction temperature, the nickel extraction efficiency is improved. 93.5% of nickel in residue is extracted under suitable leaching conditions, including particle size （0.074-0.100） mm, sulfuric acid concentration 30% （mass fraction）, temperature 80 ~C, reaction time 180 min, mass ratio of liquid to solid 10 and stirring speed 800 r/min. The leaching kinetics analyses shows that the reaction rate of leaching process is controlled by diffusion through the product layer, and the calculated activation energy of 15.8 kJ/mol is characteristic for a diffusion controlled process.展开更多
Nutrient limitation is known to inhibit growth and metabolism and to alter elemental stoichiometric ratios in phytoplankton. In this study, physiological changes in Thalassirosira weissflogii were measured under diffe...Nutrient limitation is known to inhibit growth and metabolism and to alter elemental stoichiometric ratios in phytoplankton. In this study, physiological changes in Thalassirosira weissflogii were measured under different dissolved inorganic phosphate (DIP) regimes in semi-continuous cultures to revisit the utility of the Redfield ratio for assessing nutrient limitation. The results showed that cell size increased with decreasing DIP availability. In the P-depleted treatment (f/2-P) the cell size was 1.48 times larger than that in the P-limited (f/100) treatment and 2.67 times larger than that in the P-saturated treatment (f/2 and f/10). The fucoxanthin to chlorophyll a ratio (Fuco/chl a) was relatively stable (about 0.3) in P-saturated cultures and was 10 times higher than that in P-limited and P-depleted cultures. During the experimental period, the photosynthetic efficiency index, ?F/Fm′, was relatively stable at ~0.50 in the P-saturated cultures, but quickly declined with decreasing DIP availability. Although cellular P content showed a significant difference between the P-saturated culture (1.6 pg/cell) and the P-limited culture (0.7 pg/cell), the N/P ratio in T. weissflogii did not show a trend with DIP availability and fluctuated slightly around 25. Our results suggest that cell division in T. weissflogii is not strictly size-gated but is probably regulated by a biochemical, and hence, an elemental stoichiometric ratio threshold, and that deviation of the cellular N/P ratio from the Redfield ratio is not a reliable indicator of algal nutrient stress.展开更多
The electrochemical dissolution and passivation of laser additive manufactured Ti6Al4V were investigated through Tafel polarization,potentiostatic polarization and AC impedance measurements.The results show that the s...The electrochemical dissolution and passivation of laser additive manufactured Ti6Al4V were investigated through Tafel polarization,potentiostatic polarization and AC impedance measurements.The results show that the solution treatment−aging(STA)process aggravates the element micro-segregation compared to the annealing process,leading to varied Al and V contents of the phases from different samples.It is proven that either Al-rich or V-rich condition can highly affect the electrochemical dissolution behaviors due to thermodynamical instability caused by element segregation.The dissolution rate in the metastable passivation process is controlled by the stability of the produced film that is affected by phases distribution,especially the difficult-to-dissolve phase.And then,the dissolution rate of the phases in the transpassivation region is consistent with the rank in the activation process because the dense film is not capable of being produced.Compared to the annealed sample,the higher dissolution rate of the STA sample is beneficial to the electrochemical machining(ECM)of Ti6Al4V.展开更多
This study aims to investigate methyl tert-butyl ether(MTBE) dissolution in saturated porous media.A series of1 D column experiments were conducted in laboratory to obtain MTBE dissolution data with different groundwa...This study aims to investigate methyl tert-butyl ether(MTBE) dissolution in saturated porous media.A series of1 D column experiments were conducted in laboratory to obtain MTBE dissolution data with different groundwater velocity,initial MTBE saturation and grain size of porous medium,and in the presence of other nonaqueous liquids.Results indicate that higher groundwater velocity increases MTBE dissolution rate and higher initial MTBE saturation reduces effective permeability to slow MTBE dissolution rate.Smaller grain size medium gives higher MTBE dissolution rate because of higher permeability.The addition of trichloroethylene enhances MTBE dissolution,with an optimal mass ratio of 10:2,while the presence of p-xylene prolongs complete dissolution of MTBE.Mass transfer correlations are developed for MTBE dissolution rate based on the degree of MTBE saturation Sn.Mass transfer rate is characterized by Re' with a high exponent for 0.3000<Sn<0.5482,while it is related to medium grain size and Sn for Sn≤0.3000.展开更多
Most fault-block reservoirs in Xinmu oilfield belong to heterogeneous sandstone in characters which has low permeability, and reservoir pollution is a common phenomenon in this area. Acidizing deplugging in oil wells ...Most fault-block reservoirs in Xinmu oilfield belong to heterogeneous sandstone in characters which has low permeability, and reservoir pollution is a common phenomenon in this area. Acidizing deplugging in oil wells has become one of the major measures to improve production efficiency in the field. A compound deplug- ging technology in high efficiency low corrosion is developed for this kind of low permeability sandstone reser- voir. On the basis of profoundly understanding of the reservoir＇s physical properties and sensitivity, along with comprehensive analysis of the cause for jams in oil wells, a series of experiments are carried out in order to in- vestigate the dissolution reaction among samples and deplugging inhibitor, sample dissolving speed, formation fluid compatibility, reduction of secondary pollution, etc. Considered reservoir condition in nearby wells the op- timized compositional deplugging liquid formula is selected for this reservoir. It is featured by reducing the de- plugging reaction speed, extending solution for processing radius, preventing secondary damage in dissolution processing, and removing plug pollution effectively. To implement this high efficiency low corrosion deplugging measure based on reservoir condition in the borehole and nearby wells, a relatively better result of deplugging and production increasing is achieved, which enriches the measures to increase production in Xinmu oilfield, and this method can be applied to other similar oiffields for the purpose of maintaining the crude oil production and providing assistant for increasing the production significantly.展开更多
Ultrasound assisted electrocatalytic process was used for enhancing decomposition efficiency of organic compounds. In this paper, the effect of ultrasonic frequency, ultrasonic intensity and pH value on 3-chlorophenol...Ultrasound assisted electrocatalytic process was used for enhancing decomposition efficiency of organic compounds. In this paper, the effect of ultrasonic frequency, ultrasonic intensity and pH value on 3-chlorophenol decomposition were studied. It was found that 3-chlorophenol in aqueous solution can be markedly decomposed by ultrasound assisted electrocatalytic process. The rate of decomposition increased with the increase of frequency, and low frequency is proper in the ultrasound assisted electrocatalytic system. The removal of 3-chlorophenol increased visibly with the increase of ultrasonic intensity until the intensity of 1.56 W/cm2. Alkaline condition is beneficial to 3-chlorophenol decomposition, the rate at pH 9.08 was higher than pH 2.48 and 6.85. The major intermediate formed during 3-chlorophenol decomposition was 2-chloro-pbenzoquinone, which was readily decomposed by ultrasound assisted electrocatalytic process.展开更多
文摘针对报废磷酸铁锂(LiFePO_(4)/C)在回收过程中难溶解的行业难点,对磷酸铁锂煅烧产物在硫酸(H_(2)SO_(4))和盐酸(HCl)中的溶解效率,以及相结构和质量变化进行研究.结果显示,报废的磷酸铁锂在不同煅烧温度下的产物不同,煅烧产物在酸中的溶解效率也有所差异.最佳溶解条件是将300℃的煅烧产物在60℃、30%H_(2)SO_(4)溶液中溶解1 h.
基金Project (50574101) supported by the National Natural Science Foundation of ChinaProject (2003UDBEA00C020) supported by the Collaborative Project of School and Province of Yunnan Province,China
文摘Sulfuric acid leaching process was applied to extract nickel from roasting-dissolving residue of a spent catalyst, the effect of different parameters on nickel extraction was investigated by leaching experiments, and the leaching kinetics of nickel was analyzed. The experimental results indicate that the effects of particle size and sulfuric acid concentration on the nickel extraction are remarkable; the effect of reaction temperature is mild; while the effect of stirring speed in the range of 400-1 200 r/min is negligible. Decreasing particle size or increasing sulfuric acid concentration and reaction temperature, the nickel extraction efficiency is improved. 93.5% of nickel in residue is extracted under suitable leaching conditions, including particle size （0.074-0.100） mm, sulfuric acid concentration 30% （mass fraction）, temperature 80 ~C, reaction time 180 min, mass ratio of liquid to solid 10 and stirring speed 800 r/min. The leaching kinetics analyses shows that the reaction rate of leaching process is controlled by diffusion through the product layer, and the calculated activation energy of 15.8 kJ/mol is characteristic for a diffusion controlled process.
基金Supported by CAS for Key Topics in Innovation Engineering (No. KZCX2-YW-JS206)the CAS/SAFEA International Partnership Program for Creative Research Teams (No. KZCX2-YW-T001)+1 种基金the National Natural Science Foundation of China (Nos. 41076096, 40828006, U1033003)Guangdong Natural Science Fund (No. 2010B031900039)
文摘Nutrient limitation is known to inhibit growth and metabolism and to alter elemental stoichiometric ratios in phytoplankton. In this study, physiological changes in Thalassirosira weissflogii were measured under different dissolved inorganic phosphate (DIP) regimes in semi-continuous cultures to revisit the utility of the Redfield ratio for assessing nutrient limitation. The results showed that cell size increased with decreasing DIP availability. In the P-depleted treatment (f/2-P) the cell size was 1.48 times larger than that in the P-limited (f/100) treatment and 2.67 times larger than that in the P-saturated treatment (f/2 and f/10). The fucoxanthin to chlorophyll a ratio (Fuco/chl a) was relatively stable (about 0.3) in P-saturated cultures and was 10 times higher than that in P-limited and P-depleted cultures. During the experimental period, the photosynthetic efficiency index, ?F/Fm′, was relatively stable at ~0.50 in the P-saturated cultures, but quickly declined with decreasing DIP availability. Although cellular P content showed a significant difference between the P-saturated culture (1.6 pg/cell) and the P-limited culture (0.7 pg/cell), the N/P ratio in T. weissflogii did not show a trend with DIP availability and fluctuated slightly around 25. Our results suggest that cell division in T. weissflogii is not strictly size-gated but is probably regulated by a biochemical, and hence, an elemental stoichiometric ratio threshold, and that deviation of the cellular N/P ratio from the Redfield ratio is not a reliable indicator of algal nutrient stress.
基金The authors are grateful for the financial supports from the project of Ministry of Industry and Information Technology of China(No.2019-00899-1-1)the Natural Science Foundation of Shaanxi Province,China(No.2021JM-060)Fundamental Research Funds for the Central Universities,China(No.3102019QD0409).
文摘The electrochemical dissolution and passivation of laser additive manufactured Ti6Al4V were investigated through Tafel polarization,potentiostatic polarization and AC impedance measurements.The results show that the solution treatment−aging(STA)process aggravates the element micro-segregation compared to the annealing process,leading to varied Al and V contents of the phases from different samples.It is proven that either Al-rich or V-rich condition can highly affect the electrochemical dissolution behaviors due to thermodynamical instability caused by element segregation.The dissolution rate in the metastable passivation process is controlled by the stability of the produced film that is affected by phases distribution,especially the difficult-to-dissolve phase.And then,the dissolution rate of the phases in the transpassivation region is consistent with the rank in the activation process because the dense film is not capable of being produced.Compared to the annealed sample,the higher dissolution rate of the STA sample is beneficial to the electrochemical machining(ECM)of Ti6Al4V.
基金Supported by the National Natural Science Foundation of China(41201497)
文摘This study aims to investigate methyl tert-butyl ether(MTBE) dissolution in saturated porous media.A series of1 D column experiments were conducted in laboratory to obtain MTBE dissolution data with different groundwater velocity,initial MTBE saturation and grain size of porous medium,and in the presence of other nonaqueous liquids.Results indicate that higher groundwater velocity increases MTBE dissolution rate and higher initial MTBE saturation reduces effective permeability to slow MTBE dissolution rate.Smaller grain size medium gives higher MTBE dissolution rate because of higher permeability.The addition of trichloroethylene enhances MTBE dissolution,with an optimal mass ratio of 10:2,while the presence of p-xylene prolongs complete dissolution of MTBE.Mass transfer correlations are developed for MTBE dissolution rate based on the degree of MTBE saturation Sn.Mass transfer rate is characterized by Re' with a high exponent for 0.3000<Sn<0.5482,while it is related to medium grain size and Sn for Sn≤0.3000.
文摘Most fault-block reservoirs in Xinmu oilfield belong to heterogeneous sandstone in characters which has low permeability, and reservoir pollution is a common phenomenon in this area. Acidizing deplugging in oil wells has become one of the major measures to improve production efficiency in the field. A compound deplug- ging technology in high efficiency low corrosion is developed for this kind of low permeability sandstone reser- voir. On the basis of profoundly understanding of the reservoir＇s physical properties and sensitivity, along with comprehensive analysis of the cause for jams in oil wells, a series of experiments are carried out in order to in- vestigate the dissolution reaction among samples and deplugging inhibitor, sample dissolving speed, formation fluid compatibility, reduction of secondary pollution, etc. Considered reservoir condition in nearby wells the op- timized compositional deplugging liquid formula is selected for this reservoir. It is featured by reducing the de- plugging reaction speed, extending solution for processing radius, preventing secondary damage in dissolution processing, and removing plug pollution effectively. To implement this high efficiency low corrosion deplugging measure based on reservoir condition in the borehole and nearby wells, a relatively better result of deplugging and production increasing is achieved, which enriches the measures to increase production in Xinmu oilfield, and this method can be applied to other similar oiffields for the purpose of maintaining the crude oil production and providing assistant for increasing the production significantly.
文摘Ultrasound assisted electrocatalytic process was used for enhancing decomposition efficiency of organic compounds. In this paper, the effect of ultrasonic frequency, ultrasonic intensity and pH value on 3-chlorophenol decomposition were studied. It was found that 3-chlorophenol in aqueous solution can be markedly decomposed by ultrasound assisted electrocatalytic process. The rate of decomposition increased with the increase of frequency, and low frequency is proper in the ultrasound assisted electrocatalytic system. The removal of 3-chlorophenol increased visibly with the increase of ultrasonic intensity until the intensity of 1.56 W/cm2. Alkaline condition is beneficial to 3-chlorophenol decomposition, the rate at pH 9.08 was higher than pH 2.48 and 6.85. The major intermediate formed during 3-chlorophenol decomposition was 2-chloro-pbenzoquinone, which was readily decomposed by ultrasound assisted electrocatalytic process.
