Silver ion can be useful in improving chalcopyrite bioleaching efficiency.In this work,leaching kinetics of this process was investigated using silver-bearing solid waste under different chalcopyrite/solid waste ratio...Silver ion can be useful in improving chalcopyrite bioleaching efficiency.In this work,leaching kinetics of this process was investigated using silver-bearing solid waste under different chalcopyrite/solid waste ratios.Bioleaching behavior indicates that silver-bearing solid waste can enhance the bioleaching process,and the redox potential is much higher than the proposed appropriate range(380−480 mV vs Ag/AgCl)with the solid waste added.There is a positive correlation between temperature and copper extraction rate.The kinetics data fit well with the shrinking-core model.Under these leaching conditions,the bioleaching of chalcopyrite is controlled by internal diffusion with calculated apparent activation energy(Ea)of 28.24 kJ/mol.This work is possible benificial to promote the industrial application of silver catalyst in leaching of chalcopyrite.展开更多
Biowaste compost can influence soil organic matter accumulation directly or indirectly. A 5-year experiment was conducted to assess the influence of biowaste compost on the process of soil aggregation and soil organic...Biowaste compost can influence soil organic matter accumulation directly or indirectly. A 5-year experiment was conducted to assess the influence of biowaste compost on the process of soil aggregation and soil organic carbon （SOC） accumulation in a Mediterranean vegetable cropping system. The study involved four treatments： biowaste compost （COM）, mineral NPK fertilizers （MIN）, biowaste compost with half-dose N fertilizer （COMN）, and unfertilized control （CK）. The SOC stocks were increased in COM, COMN, and MIN by 20.2, 14.9, and 2.4 Mg ha-1 over CK, respectively. The SOC concentration was significantly related to mean weight diameter of aggregates （MWD） （P 〈 0.05, R^2 = 0.798 4） when CK was excluded from regression analysis. Compared to CK, COM and COMN increased the SOC amount in macroaggregates （〉 250 μm） by 2.7 and 0.6 g kg-1 soil, respectively, while MIN showed a loss of 0.4 g kg-1 soil. The SOC amount in free microaggregates （53-250 ttm） increased by 0.9, 1.6, and 1.0 g kg-1 soil for COM, COMN, and MIN, respectively, while those in the free silt plus clay aggregates （~ 53 ~m） did not vary significantly. However, when separating SOC in particle-size fractions, we found that more stable organic carbon associated with mineral fraction 〈 53 μm （MOM-C） increased significantly by 3.4, 2.2, and 0.7 g kg-1 soil for COM, COMN, and MIN, respectively, over CK, while SOC amount in fine particulate organic matter （POM） fraction （53-250 μm） increased only by 0.3 g kg-1 soil for both COM and COMN, with no difference in coarse POM 〉 250 μm. Therefore, we consider that biowaste compost could be effective in improving soil structure and long-term C sequestration as more stable MOM-C.展开更多
基金Project(2018JJ1041)supported by the Natural Science Foundation of Hunan,ChinaProjects(51774332,U1932129,51804350 and 51934009)supported by the National Natural Science Foundation of China。
文摘Silver ion can be useful in improving chalcopyrite bioleaching efficiency.In this work,leaching kinetics of this process was investigated using silver-bearing solid waste under different chalcopyrite/solid waste ratios.Bioleaching behavior indicates that silver-bearing solid waste can enhance the bioleaching process,and the redox potential is much higher than the proposed appropriate range(380−480 mV vs Ag/AgCl)with the solid waste added.There is a positive correlation between temperature and copper extraction rate.The kinetics data fit well with the shrinking-core model.Under these leaching conditions,the bioleaching of chalcopyrite is controlled by internal diffusion with calculated apparent activation energy(Ea)of 28.24 kJ/mol.This work is possible benificial to promote the industrial application of silver catalyst in leaching of chalcopyrite.
文摘Biowaste compost can influence soil organic matter accumulation directly or indirectly. A 5-year experiment was conducted to assess the influence of biowaste compost on the process of soil aggregation and soil organic carbon （SOC） accumulation in a Mediterranean vegetable cropping system. The study involved four treatments： biowaste compost （COM）, mineral NPK fertilizers （MIN）, biowaste compost with half-dose N fertilizer （COMN）, and unfertilized control （CK）. The SOC stocks were increased in COM, COMN, and MIN by 20.2, 14.9, and 2.4 Mg ha-1 over CK, respectively. The SOC concentration was significantly related to mean weight diameter of aggregates （MWD） （P 〈 0.05, R^2 = 0.798 4） when CK was excluded from regression analysis. Compared to CK, COM and COMN increased the SOC amount in macroaggregates （〉 250 μm） by 2.7 and 0.6 g kg-1 soil, respectively, while MIN showed a loss of 0.4 g kg-1 soil. The SOC amount in free microaggregates （53-250 ttm） increased by 0.9, 1.6, and 1.0 g kg-1 soil for COM, COMN, and MIN, respectively, while those in the free silt plus clay aggregates （~ 53 ~m） did not vary significantly. However, when separating SOC in particle-size fractions, we found that more stable organic carbon associated with mineral fraction 〈 53 μm （MOM-C） increased significantly by 3.4, 2.2, and 0.7 g kg-1 soil for COM, COMN, and MIN, respectively, over CK, while SOC amount in fine particulate organic matter （POM） fraction （53-250 μm） increased only by 0.3 g kg-1 soil for both COM and COMN, with no difference in coarse POM 〉 250 μm. Therefore, we consider that biowaste compost could be effective in improving soil structure and long-term C sequestration as more stable MOM-C.
